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Home | Alpha Telephone | Domain Names | Web Hosting | Get Traffic | xrEvidence | xrSoccer United States Patent
Coordinate position inputting/detecting device, a method for inputting/detecting the coordinate position, and a display board system The coordinate-position inputting/detecting device comprises a lighting device for emitting light into an entry area into which an arbitrary pointing body is inserted to perform an entry operation. At least two image pickup devices are provided with a prespecified space therebetween on a peripheral section of the entry area for picking up images of the pointing body illuminated by the light from the lighting device. Position on the CCD of the image pickup devices where an image of the pointing body is formed is obtained according to output from each of the image pickup devices. Coordinates of the position of the pointing body in the entry area are calculated from these positions.
Assistant Examiner: Monestime; Mackly Attorney, Agent or Firm: What is claimed is: 1. A coordinate-position inputting/detecting device comprising: at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area, the at least two image pickup elements each providing an output indicating a portion of each of the at least two image pickup elements receiving an illuminated image of a pointing body inserted into said entry area to perform an entry operation; coordinate-value identifying means for computing positions where each illuminated image is formed on each of said at least two image pickup elements according to each corresponding output from said at least two image pickup elements and for identifying coordinates of a position of said pointing body by using the computed positions; storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates; determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not; and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 2. A coordinate-position inputting/detecting device according to claim 1 further comprising distortion correcting means for electrically correcting optical distortion of each illuminated image formed on each of said at least two image pickup elements. 3. A coordinate-position inputting/detecting device according to claim 1 further comprising pattern recognizing means for recognizing patterns according to each output from each of the at least two image pickup elements when a plurality of pointing bodies, each having a different pattern provided thereon, are inserted into said entry area. 4. A coordinate-position inputting/detecting device comprising: light emitting means provided at a first location for emitting light into an entry area; at least two image pickup elements that are positioned to be remote from the first location and provided with a prespecified space therebetween on a peripheral section of said entry area and with an orientation so that each of the at least two image pickup elements receives illuminated images made up of light reflected from a pointing body inserted into the entry area and illuminated by the light emitted from said light emitting means; coordinate-value identifying means receiving an output from each of the at least two image pickup elements resulting from corresponding illuminated images made up of light reflected from the pointing body impinging thereon and using each of the outputs for computing corresponding positions where the illuminated images of said pointing body are formed on corresponding ones of said at least two image pickup elements, and for identifying coordinates of a position of said pointing body by using the computed positions; storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates; determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not; and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 5. A coordinate-position inputting/detecting device according to claim 4; wherein said light emitting means and said at least two image pickup elements are all positioned on a same side of the entry area. 6. A coordinate-position inputting/detecting device according to claim 4; wherein said light emitting means has incident light preventing means for preventing the emitted light from the light emitting means from directly entering into each of said at least two image pickup elements. 7. A coordinate-position inputting/detecting device according to claim 4; wherein said light emitting means has at least a light source for emitting light; and a mirror for reflecting the light from the light source thereon and diffusing the light along said entry area. 8. A coordinate-position inputting/detecting device according to claim 7 further comprising adjusting means for changing an angle of said mirror to adjust a direction of reflecting the light. 9. A coordinate-position inputting/detecting device according to claim 8; wherein said adjusting means comprises: a light receiving element for receiving the light reflected by said mirror; driving means for changing the angle of said mirror; and control means for controlling said driving means in order to change the angle of said mirror according to intensity of the light received by said light receiving element. 10. A coordinate-position inputting/detecting device according to claim 4 further comprising reflection preventing means for preventing light emitted from said light emitting means and passing through the entry area from being reflected back into the entry area. 11. A coordinate-position inputting/detecting device according to claim 4 further comprising distortion correcting means for electrically correcting optical distortion of the illuminated images formed on each of said at least two image pickup elements. 12. A coordinate-position inputting/detecting device according to claim 4 further comprising pattern recognizing means for recognizing patterns according to each output from each of the at least two image pickup elements when a plurality of pointing bodies, each having a different pattern provided thereon, are inserted into said entry area. 13. A coordinate-position inputting/detecting device according to claim 4 further comprising a width identifying means for identifying a width of said pointing body according to the illuminated images formed on each of the at least two image pickup elements. 14. A coordinate-position inputting/detecting device according to claim 13 further comprising correcting means for correcting the coordinates identified by said coordinate-value identifying means using the width identified by said width identifying means. 15. A coordinate-position inputting/detecting device comprising: at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area into which an arbitrary pointing body is inserted to perform an entry operation; first storing means for storing therein images of said entry area previously picked up by each of said at least two image pickup elements as corresponding reference images; extracting means for extracting differential images of the arbitrary pointing body inserted into said entry area from corresponding present images of said entry area picked up by each of said at least two image pickup elements when the arbitrary pointing body is inserted into the entry area by obtaining a difference between each of the corresponding present images and a corresponding one of said reference images; and coordinate-value identifying means for computing positions where each extracted differential image of said arbitrary pointing body is formed on each corresponding one of said image pickup elements, and for identifying coordinates of a position of said arbitrary pointing body by using the computed positions. 16. A coordinate-position inputting/detecting device according to claim 15 further comprising a background plate provided at a location which is on a peripheral section of said entry area included in a field of view of each of said at least two image pickup elements. 17. A coordinate-position inputting/detecting device according to claim 16; wherein said background plate has an arbitrary pattern provided thereto. 18. A coordinate-position inputting/detecting device according to claim 15 further comprising area restricting means for restricting an imaging area covered by each of said at least two image pickup elements so that the imaging area covered is adjusted to said entry area. 19. A coordinate-position inputting/detecting device according to claim 15 further comprising: second storing means for storing therein the coordinates first identified by said coordinate-value identifying means as first coordinates; determining means for determining whether the first coordinates stored in said second storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not; and updating means for replacing the first coordinates stored in said second storing means with said updated coordinates and outputting the updated coordinates to an external device when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 20. A coordinate-position inputting/detecting device according to claim 19 further comprising image updating means for storing each image of said entry area used for identifying the coordinates of the position abandoned by said updating means in to said first storing means as a new reference image. 21. A coordinate-position inputting/detecting device comprising: at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area, the at least two image pickup elements being configured to provide an output indicating a portion of each of the at least two image pickup elements receiving an illuminated image of a pointing body inserted into said entry area to perform an entry operation; and a coordinate-value identifying unit configured to compute positions where each illuminated image is formed on each of said at least two image pickup elements according to each corresponding output from said at least two image pickup elements, and further configured to identify coordinates of a position of said pointing body by using the computed positions, wherein the coordinate-value identifying unit further comprises, a store configured to store the coordinates first identified by said coordinate-value identifying unit as first coordinates, a determining unit configured to determine whether the first coordinates stored in said store are coincident with updated coordinates newly identified by said coordinate-value identifying unit or not, and an updating unit configured to replace the first coordinates stored in said store with said updated coordinates and outputting the updated coordinates when it is determined by said determining unit that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining unit that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 22. A coordinate-position inputting/detecting device comprising: a light emitting element provided at a first location and configured to emit light into an entry area; at least two image pickup elements that are positioned to be remote from the first location and provided with a prespecified space therebetween on a peripheral section in part defining said entry area and with an orientation so that each of the at least two image pickup elements receives illuminated images made up of light reflected from a pointing body inserted into the entry area and illuminated by the light emitted from said light emitting element; and a coordinate-value identifying unit configured to receive an output from each of the at least two image pickup elements resulting from corresponding illuminated images made up of light reflected from the pointing body impinging thereon and using each of the outputs for computing corresponding positions where the illuminated images are formed on corresponding ones of said at least two image pickup means, and further configured to identify coordinates of a position of said pointing body by using the computed positions, wherein the coordinate-value identifying unit further comprises, a store configured to store the coordinates first identified by said coordinate-value identifying unit as first coordinates, a determining unit configured to determine whether the first coordinates stored in said store are coincident with updated coordinates newly identified by said coordinate-value identifying unit or not, and an updating unit configured to replace the first coordinates stored in said store with said updated coordinates and outputting the updated coordinates when it is determined by said determining unit that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining unit that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 23. A coordinate-position inputting/detecting device comprising: at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area into which an arbitrary pointing body is inserted to perform an entry operation; a first memory for storing therein images of said entry area previously picked up by each of said at least two image pickup elements as corresponding reference images; an extracting unit configured to extract differential images of the arbitrary pointing body inserted into said entry area from corresponding present images of said entry area picked up by each of said at least two image pickup elements when the arbitrary pointing body is inserted into the entry area by obtaining a difference between each of the corresponding present images and a corresponding one of said reference images; and a coordinate-value identifying unit configured to compute positions where each extracted differential image of said pointing body is formed on each corresponding one of said image pickup elements, and further configured to identify coordinates of a position of said pointing body by using the computed positions. 24. A coordinate-position inputting/detecting method comprising the steps of: obtaining an illuminated image of an arbitrary pointing body inserted into an entry area on each of at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of the entry area; providing an output from each of the at least two image pickup elements that indicates a portion on the corresponding one of the at least two image pickup elements having the corresponding illuminated image formed thereon; computing positions where each of the illuminated images are formed on a corresponding one of said at least two image pickup elements according to each output; and identifying coordinates of a position of said arbitrary pointing body in the entry area from the computed positions, wherein said step of identifying coordinates further comprises, storing an indication of the coordinates initially identified in a store, determining whether or not the stored initially identified coordinates are coincident with updated coordinates later identified, and replacing the indication of the coordinates as initially identified in the store with said updated coordinates and outputting the updated coordinates when it is determined by said determining step that the stored initially identified coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining step that the stored initially identified coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 25. A coordinate-position inputting/detecting method comprising the steps of: emitting light into an entry area from a first location; inserting a pointing body into the entry area to intercept and reflect the light to provide an entry operation; obtaining an image of the pointing body in the form of the light reflected from the pointing body on each one of at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of the entry area at two different locations remote from the first location; providing an output from each of the at least two image pickup elements that indicates where on the corresponding one of the at least two image pickup elements the corresponding image of the pointing body is formed; computing positions where each corresponding image of said pointing body is formed on each of said image pickup elements according to each output; and identifying coordinates of a position of said pointing body in the entry area from the computed positions, wherein said step of identifying coordinates further comprises, storing an indication of the coordinates initially identified in a store, determining whether or not the stored initially identified coordinates are coincident with updated coordinates later identified, and replacing the indication of the coordinates as initially identified in the store with said updated coordinates and outputting the updated coordinates when it is determined by said determining step that the stored initially identified coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining step that the stored initially identified coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 26. A coordinate-position inputting/detecting method comprising the steps of: providing at least two image pickup elements on a peripheral section of an entry area that are spaced apart by a predetermined distance; obtaining corresponding reference images of said entry area as viewed from each of the at least two image pickup elements; inserting a pointing body into the entry area; forming corresponding entry images of the entry area containing the inserted pointing body using each of the at least two image pickup elements; extracting corresponding differential images of the pointing body by determining differences between the corresponding entry images and the corresponding reference images; computing positions where each of the corresponding differential images of said pointing body is formed on each of said at least two image pickup elements; and identifying coordinates of a position of said pointing body in the entry area from the computed positions. 27. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; and control means for providing controls over display by said display means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of a display board and said coordinate-position inputting/detecting device comprises, at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area into which a pointing body is inserted to perform an entry operation including forming illuminated images of the pointing body inserted into said entry area on a portion of each of the at least two image pickup elements with each of the at least two image pickup elements providing an output corresponding to the portion of each that the illuminated images are formed on, coordinate-value identifying means for computing positions where the illuminated images of said pointing body are formed according to each output from each of the at least two image pickup elements, and for identifying coordinates of a position of said pointing body by using the computed positions, storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates, determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not, and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 28. A display board system according to claim 27; wherein said display means is a plasma display. 29. A display board system according to claim 27; wherein said display means further has a plurality of connecting means for connecting various types of information equipment including video equipment, and is usable as a large-sized screen monitor using said connecting means. 30. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; and control means for providing controls over display by said display means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of a display board and said coordinate-position inputting/detecting device comprises, light emitting means at a first location for emitting light into an entry area into which a pointing body is inserted to perform an entry operation, at least two image pickup elements located remotely from the first location and provided with a prespecified space therebetween on a peripheral section of said entry area for picking up illuminated images of said pointing body illuminated by the light emitted from said light emitting means, with each of the at least two image pickup elements providing an output corresponding to the illuminated images formed thereon, coordinate-value identifying means for computing positions where the illuminated images of said pointing body are formed on each of the at least two image pickup elements according to each output from the at least two image pickup elements, and for identifying coordinates of a position of said pointing body by using the computed positions, storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates, determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not, and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time. 31. A display board system according to claim 30; wherein said display means is a plasma display. 32. A display board system according to claim 30; wherein said display means further has a plurality of connecting means for connecting various types of including video equipment, and is usable as a large-sized screen monitor using said connecting means. 33. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; and control means for providing controls over display by said display means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of a display board and said coordinate-position inputting/detecting device comprises, at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area into which a pointing body is inserted to perform an entry operation for picking up images of the pointing body, first storing means for storing therein images of said entry area previously picked up by each of the at least two image pickup elements as corresponding reference images, extracting means for extracting differential images of the pointing body inserted into said entry area from corresponding present images of said entry area picked up by each of the at least two image pickup elements when the pointing body is inserted into the entry area by obtaining a difference between each of the corresponding present images and a corresponding one of said reference images; and coordinate-value identifying means for computing positions where each extracted differential image of said pointing body is formed on each corresponding one of the image pickup elements, and identifying coordinates of a position of said pointing body by using the computed positions. 34. A display board system according to claim 33; wherein said display means is a plasma display. 35. A display board system according to claim 33; wherein said display means further has a plurality of connecting means for connecting various types of information equipment including video equipment, and is usable as a large-sized screen monitor using said connecting means. 36. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display by said display means as well as over printing operations by said printing means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of the display board and said coordinate-position inputting/detecting device comprises, at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area, the at least two image pickup elements each providing an output indicating a portion of each of the at least two image pickup elements receiving an illuminated image of a pointing body inserted into said entry area to perform an entry operation, coordinate-value identifying means for computing positions where each illuminated image is formed on each of the at least two image pickup elements according to each corresponding output from the at least two image pickup elements, and for identifying coordinates of a position of said pointing body by using the computed positions, storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates, determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not, and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time; and further wherein said control means is a personal computer and said display board system further comprises, a frame unit having holding means for holding the display surface and the writing surface of the display board at a specified height, a printer accommodating means for accommodating said printing means therein, and control accommodating means for accommodating said control means therein, wherein said control accommodating means and said printer accommodating means are arranged in the frame unit beneath the holding means. 37. A display board system according to claim 36; wherein said display means is a plasma display. 38. A display board system according to claim 36; wherein said frame unit has a keyboard placement means provided at a position on the upper side of said printer accommodating means but on the lower side of said holding means for placing a keyboard connected to said personal computer. 39. A display board system according to claim 36; wherein said holding means includes an angle adjusting means for adjusting an angle of the display surface and the writing surface of the display board. 40. A display board system according to claim 36; wherein said display means further has a plurality of connecting means for connecting various types of information equipment including video equipment, and is usable as a large-sized screen monitor using said connecting means. 41. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display by said display means as well as over printing operations by said printing means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of the display board and said coordinate-position inputting/detecting device comprises, light emitting means for emitting light into an entry area, at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of said entry area for picking up illuminated images made up of light reflected from a pointing body inserted into the entry area and illuminated by the light emitted from said light emitting means, and coordinate-value identifying means receiving an output from each of the at least two image pickup elements resulting from corresponding illuminated images made up of light reflected from the pointing body impinging thereon and using each of the outputs for computing corresponding positions where the illuminated images of said pointing body are formed on corresponding ones of the at least two image pickup elements, and for identifying coordinates of a position of said pointing body by using the computed positions, storing means for storing the coordinates first identified by said coordinate-value identifying means as first coordinates, determining means for determining whether the first coordinates stored in said storing means are coincident with updated coordinates newly identified by said coordinate-value identifying means or not, and updating means for replacing the first coordinates stored in said storing means with said updated coordinates and outputting the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are not coincident, while abandoning the updated coordinates when it is determined by said determining means that the first coordinates and the updated coordinates are coincident and are continuously identified as being coincident over a prespecified period of time, and further wherein said control means is a personal computer and said display board system further comprises, a frame unit having holding means for holding the display surface and the writing surface of the display board at a specified height, a printer accommodating means for accommodating said printing means therein, and control accommodating means for accommodating said control means therein, wherein said control accommodating means and said printer accommodating means are arranged in the frame unit beneath the holding means. 42. A display board system according to claim 41; wherein said display means is a plasma display. 43. A display board system according to claim 41; wherein said frame unit has a keyboard placement means provided at a position on the upper side of said printer accommodating means but on the lower side of said holding means for placing a keyboard connected to said personal computer. 44. A display board system according to claim 41; wherein said holding means includes an angle adjusting means for adjusting an angle of the display surface and the writing surface of the display board. 45. A display board system according to claim 41; wherein said display means further has a plurality of connecting means for connecting various types of information equipment including video equipment, and is usable as a large-sized screen monitor using said connecting means. 46. A display board system comprising at least: display means for displaying characters and images; a coordinate-position inputting/detecting device with an entry area provided in front of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display by said display means as well as over printing operations by said printing means according to input from said coordinate-position inputting/detecting device, wherein the display means forms a display surface and the coordinate-position inputting/detecting device forms a writing surface of the display board and said coordinate-position inputting/detecting device comprises, at least two image pickup elements provided with a prespecified space therebetween on a peripheral section of an entry area into which an arbitrary pointing body is inserted to perform an entry operation, first storing means for storing therein images of said entry area previously picked up by each of the at least two image pickup elements as corresponding reference images, extracting means for extracting differential images of the arbitrary pointing body inserted into said entry area from corresponding present images of said entry area picked up by each of the at least two image pickup elements when the arbitrary pointing body is inserted into the entry area by obtaining a difference between each of the corresponding present images and a corresponding one of said reference images, coordinate-value identifying means for computing positions where each extracted differential image of said arbitrary pointing body is formed on each corresponding one of the image pickup elements, and for identifying coordinates of a position of said arbitrary pointing body by using the computed positions, and further wherein said control means is a personal computer and said display board system further comprises, a frame unit having holding means for holding the display surface and the writing surface of the display board at a specified height, a printer accommodating means for accommodating said printing means therein, and control accommodating means for accommodating said control means therein, wherein said control accommodating means and said printer accommodating means are arranged in the frame unit beneath the holding means. 47. A display board system according to claim 46; wherein said display means is a plasma display. 48. A display board system according to claim 46; wherein said frame unit has a keyboard placement means provided at a position on the upper side of said printer accommodating means but on the lower side of said holding means for placing a keyboard connected to said personal computer. 49. A display board system according to claim 46; wherein said holding means includes an angle adjusting means for adjusting an angle of the display surface and the writing surface of the display board. 50. A display board system according to claim 46; wherein said display means further has a plurality of connecting means for connecting various types of information equipment including video equipment, and is usable as a large-sized screen monitor using said connecting means. FIELD OF THE INVENTION The present invention relates to a method and device for inputting/detecting the coordinate position and a display board system and more particularly, to a method and device for enabling input and/or detection of coordinates of not only a two-dimensional position but also a three-dimensional position with improved operability as well as a display board system which uses the coordinate-position inputting/detecting device. BACKGROUND OF THE INVENTION Conventionally there has been known a display board which can read freehand information written on a whiteboard or on a writing surface of a writing sheet with some writing tool using a dedicated scanner and output the read information onto a recording paper with a dedicated printer. While, in recent years, there has also been suggested a display board system in which a coordinate-position inputting/detecting device is provided in a writing surface of a display board for enabling inputting of freehand information written in the writing surface in real time. For instance, the Soft Board manufactured and provided by the Microfield Graphics, Inc. is a device having a coordinate-position inputting/detecting device provided on a whiteboard. This Soft Board can acquire visual data such as characters and pictures drawn on the whiteboard into a computer in real time. With the display board system using this Soft Board, it is possible to input visual data captured with the Soft Board into a computer for displaying the data on a CRT thereof. The data may be displayed on a large-sized screen using a liquid crystal projector, or the data may be printed on a recording paper using a printer. It is also possible to project an image on a screen of a computer with the Soft Board connected thereto onto the Soft Board with a liquid crystal projector and operate the computer on the screen of the Soft Board. There has also been disclosed a display board system having a display unit for displaying characters and images thereon, a coordinate-position inputting/detecting device with a coordinate-position input surface (a touch screen) provided on a front surface of the display unit, and a control unit for providing controls over display by the display unit according to input from the coordinate-position inputting/detecting device. This system forms a display surface and a writing surface of the display board by making use of the display unit and the coordinate-position inputting/detecting device. For instance, in case of the Smart 2000 manufactured and supplied by the SMART Technologies Inc., when an image of a character, a picture, or a graphics is projected with a liquid crystal projector connected to a computer onto a panel, freehand information is captured into the computer using a coordinate-position inputting/detecting device (writing surface) provided on a front surface of the projection surface (display surface) of the panel. Then, the freehand information is synthesized with the image information in the computer, and the synthesized information can be displayed again with the liquid crystal projector in real time. The display board system can display an image inputted by the coordinate-position inputting/detecting device that is superimposed on an image on the screen displayed by the display unit as an overwritten. Because of this characteristics, this display board system has been used in conferences, presentations, or for educational purposes and its effect in actual use has been highly evaluated. When a communicating function for transferring audio or video data is integrated with the display board system as described above, the display board system can also be used as an electronic conference system by connecting remote sites with a communication line. By the way, as a coordinate-position inputting/detecting device used in the display board system as described above, devices described below are known according to a difference between input methods thereof. As a first case, there is an optical coordinate-position inputting/detecting device disclosed in Japanese Patent Laid-Open Publication No. HEI 8-240407. This coordinate-position inputting/detecting device has two infrared CCD cameras and these cameras detect a peak signal of an infrared ray from the infrared LED provided on a pen-type pointing body inserted in a coordinate-position entry area with the infrared CCD camera to compute a coordinate position pointed by the pointing body. As a second case, there is an optical coordinate-position inputting/detecting device disclosed in Japanese Patent Laid-Open Publication No. HEI 9-319501. In this coordinate-position inputting/detecting device, the coordinate entry area is scanned with a laser beam. A pen pen-type pointing body with a corner cube reflector as a recursive reflecting member provided thereon is inserted into the coordinate entry area and an arbitrary position is pointed thereby. Light is recursively reflected by the pointing body. The reflected light is received by a plurality of light-receiving elements and a position pointed by the pointing body is computed. With the coordinate-position inputting/detecting device in the above mentioned case, however, as a dedicated pointing body is required for pointing to an arbitrary position in the coordinate entry area, an input operation with, for example, a fingertip, is not allowed, which is inconvenient. Furthermore, when the dedicated pointing body is lost or damaged, the input operation using the coordinate-position inputting/detecting device can not be carried out. On the other hand, in the coordinate-position inputting/detecting device in the first case, an infrared LED has to be provided in a pointing body, therefore, power unit or so for the pointing body is required, which is inconvenient from the view point of its maintenance. Furthermore, in the coordinate-position inputting/detecting device, coordinates of only a two-dimensional (X-Y direction) position can be inputted, therefore, it is difficult to determine movement of a pointing body in the vertical direction (Z direction) and a double click or the like. SUMMARY OF THE INVENTION It is an object of the present invention to improve, for the purpose of solving the problems described above, operability and usability of a method and device for inputting/detecting the coordinate position by enabling specification of coordinates of a position in an entry area pointed thereto with an arbitrary pointing body such as a fingertip or an ordinary pen without using a particular pointing device. It is another object of the present invention to realize a coordinate-position inputting/detecting device enabling entry of not only a two-dimensional position but also a three-dimensional position. It is another object of the present invention to improve workability and adaptability to handling of a display board system by using the coordinate-position inputting/detecting device with excellent operability. In the present invention, an image of a pointing body inserted into an entry area is picked up by at least two image pickup elements. Then, the position of the image of the pointing body formed on each of the image pickup elements is obtained according to the output from each of the image pickup elements. Finally, coordinates of the position of the pointing body are identified by using the computed positions of the images. Therefore, entry operation can be carried out using an arbitrary pointing body without using a particular pointing body. In the present invention, light is emitted from light emitting unit into the entry area. An image of a pointing body illuminated by the light emitted from the light emitting unit is picked up by at least two image pickup elements. Then, the position of the image of the pointing body formed on each of the image pickup elements is obtained according to the output from each of the image pickup elements. Finally, coordinates of the position of the pointing body are identified by using the computed positions of the images. Therefore, an entry operation can be carried out using an arbitrary pointing body without using a particular pointing body. In the present invention, the light emitting unit and the image pickup devices are so placed that the direction of the light emitted from the light emitting units is substantially the same as the direction from which the pointing body is viewed from each of the image pickup elements. Therefore, the light emitted from the light emitting unit does not directly enter the image pickup elements, and also shadow is not generated on the pointing body as much as possible. In the present invention, there is provided an incident light preventing unit for preventing the light emitted from the light emitting unit from directly entering into each of the image pickup elements. Therefore, the light emitted from the light emitting means does not directly enter into the image pickup elements. In the present invention, the light emitting unit comprises at least a light source and a mirror. Therefore, the light emitted by the light source can be reflected by the mirror and diffused along the entry area, so that, a light that covers the entire entry area can be emitted from the light emitting unit. In the present invention, the angle of the light emitted by the light source can be changed by operating the mirror, so that, direction in which the light is reflected from the mirror can be adjusted. In the present invention, light reflected by a mirror is received by a light receiving element, and the angle of the mirror is changed according to intensity of the light received by the light receiving element. In the present invention, there is provided a reflection preventing unit which prevents the light emitted by the light emitting unit from its being reflected, so that unnecessary light does not enter the image pickup elements. In the present invention, when coordinates of the same position are obtained continuously then it is determined that the coordinates are obtained due to dust or something. In such a case the coordinates of this position are not stored in the memory and also are not outputted to an external device. As a result, it is possible to prevent coordinates of the position obtained due to dust or something from its being outputted to an external device. In the present invention, optical distortion of an image of a pointing body picked up by each of image pickup elements is electrically corrected, and higher quality of an image of a pointing body can be obtained. In the present invention, when a plurality of pointing bodies each with a different pattern provided thereto are inserted into the entry area, patterns are recognized according to each output from the image pickup elements, which allows an entry operation concurrently using the plurality of pointing bodies to be carried out. In the present invention, width of the pointing body is determined according to images of the pointing body picked up by image pickup elements. In the present invention, the coordinates of the position of a pointing body identified by coordinate-value identifying unit is corrected by using the width of the pointing body obtained by the width identifying unit so that it is possible to obtain coordinates of an accurate position. In the present invention, image of an entry area previously picked up by each of image pickup elements is stored as a reference image, images of the entry area picked up afterward by each of the image pickup elements are extracted. Then, a difference between the corresponding reference images and images of the pointing body inserted into the entry area obtained by the corresponding image pickup elements is extracted. From this difference, a position in the image of each of the image pickup elements where an image of the pointing body is formed is computed and coordinates of the position of the pointing body are obtained using the computed positions of the pointing body. In the present invention, image of the entry area is picked up utilizing two-dimensional image pickup elements, which allows coordinates of a three-dimensional position of a pointing body to be computed. In the present invention, a reference image consists of an image only of a background plate, so that an image of only a pointing body can easily be extracted from an image with the background plate and the pointing body included therein. In the present invention, image of the pointing body can easily be extracted just by removing a reference pattern from an image in which the background plate and the pointing body is present. In the present invention, an area photographable by the image pickup element is restricted by an area restricting unit so that the area is adjusted to the entry area. Therefore, the image pickup element may not be affected by noise such as interference light. In the present invention, when coordinates of the same position are obtained continuously then it is determined that the coordinates are obtained due to dust or something. In such a case the coordinates of this position are not stored in the memory and also are not outputted to an external device. As a result, it is possible to prevent coordinates of the position obtained due to dust or something from its being outputted to an external device. In the present invention, by deciding each image of an entry area used to compute coordinates of a position abandoned by updating means as each new reference image, dust existing on the entry area is taken in as a portion of a reference image. Therefore, it is prevented that coordinates of a position of dust are disadvantageously computed. In the present invention, a coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying characters and images, and a display surface and a writing surface of a display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved. In the present invention, a coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying thereon characters and images. As a result, a display surface and a writing surface of the display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved. Furthermore, the display board system comprises a frame unit having a holding section for holding a display surface and a writing surface of the display board at a specified height, a printer accommodating section for accommodating the printer therein, and a control unit accommodating section for accommodating the control unit therein. The control unit accommodating section, printer accommodating section and the holding section are arranged in the vertical direction in this order from the bottom. As a result, transport and installation of the system can easily be carried out. In the present invention, by using a plasma display as a display unit, optimization of the display board system can be performed. Namely, use of the plasma display allows the thickness of a display unit to be reduced, and the plasma display also has high brightness as well as a wide viewing angle, and can reproduce moving pictures smoothly, so that the plasma display is preferable as a display unit of the display board system. In the present invention, a keyboard placement section for placing a keyboard connected to a personal computer is provided at a position in the upper side of the printer accommodating section and in the lower side of the holding section. Therefore, handling capability of the system is improved. In the present invention, an angle adjusting unit for adjusting an angle of a display surface and a writing surface of the display board is provided in a holding section. Therefore, disturbance light coming into the display unit (display surface), especially, light from lighting equipment such as a fluorescent tube on the ceiling can be prevented. In the present invention, a plurality of connecting terminals for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment are provided in a display unit and is usable as a large-sized screen monitor. Therefore, the display board system can be used in any occasion. Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing general configuration of a coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 2 shows general configuration of a lighting device of the coordinate-position inputting/detecting device shown in FIG. 1; FIG. 3 is a block diagram of the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 4 shows the processing for computing coordinates of a position of a pointing body inserted into the entry area in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 5 shows the processing for computing coordinates of a position of a pointing body inserted into the entry area in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 6 is a graph showing a relation between a position of an image of an object formed on a CCD and light quantity of the image of the object picked up by the CCD in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 7 shows a shadow produced on the pointing body in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 8 is a graph showing a comparison between the case where there is a shadow on the pointing body to the case where there is no shadow thereon concerning a relation between a position of an image of an object formed on the CCD and light quantity of the image of the object picked up by the CCD in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 9 is a graph showing a relation between a position of an image of an object formed on a CCD, light quantity of the image of the object picked up by the CCD, and a distance D in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 10 is a flow chart showing the processing when coordinates of a computed position are transferred to a computer in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 11 shows the processing when an operation of inputting freehand characters and graphics into a computer is performed concurrently using two pens in the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 12 is a front view showing general configuration of a modification of the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 13 is a front view showing general configuration of a coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 14 shows a background plate provided in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 15 shows a light shielding plate provided in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 16 is a cross-sectional view of the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 17 is a block diagram of the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 18 shows the processing for computing coordinates of a position of a pointing body inserted into the entry area in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 19 shows the processing for computing coordinates of a position of a pointing body inserted into the entry area in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 20 is an explanatory view showing a flow of the processing for computing coordinates of a position of a pointing body inserted into the entry area in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 21 is an explanatory view showing an example of a reference image shown in FIG. 20; FIG. 22 is an explanatory view showing an example of a photographed image shown in FIG. 20; FIG. 23 is an explanatory view showing an example of a differential image shown in FIG. 20; FIG. 24 is an explanatory view showing how a point in the entry area is pointed with a finger in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 25 is an explanatory view showing a relation between a central point of an image of a differential image in the Z direction formed in a two-dimensional image sensor and a distance D in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 26A and FIG. 26B are explanatory views showing a drawing and a gesture command usable in the coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 27 is a block diagram of a display board system according to Embodiment 3 of the present invention; FIG. 28 is a block diagram of a computer (personal computer) of a display board system according to Embodiment 3 of the present invention; FIG. 29 is a perspective front view of a frame unit with the display board system according to Embodiment 3 of the present invention accommodated therein; FIG. 30 is a perspective rear view of the frame unit with the display board system according to Embodiment 3 of the present invention accommodated therein; FIG. 31 is a side view of the frame unit according to Embodiment 3 of the present invention viewed from the right side thereof; FIG. 32 shows the configuration of an angle adjusting mechanism section according to Embodiment 3 of the present invention viewed from the upper side of the frame unit (angle of the board section is five degrees); FIG. 33 shows the configuration of the angle adjusting mechanism section according to Embodiment 3 of the present invention viewed from the upper side of the frame unit (angle of the board section is zero degree); FIG. 34 shows the configuration of the angle adjusting mechanism section according to Embodiment 3 of the present invention viewed from the side of the frame unit; FIG. 35 shows a modification of the angle adjusting mechanism section according to Embodiment 3 of the present invention; FIG. 36 shows another modification of the angle adjusting mechanism section according to Embodiment 3 of the present invention; FIG. 37 shows an example of the screen of the display board and a toolbar displayed on the PDP in the display board system according to Embodiment 3 of the present invention; FIG. 38 shows an example of an extension toolbar displayed on the PDP in the display board system according to Embodiment 3 of the present invention; FIG. 39 shows an example of a drawing toolbar together with the extension toolbar displayed on the PDP in the display board system according to Embodiment 3 of the present invention; FIG. 40 shows an example of how a result of freehand characters and lines on the touch surface is displayed on the screen of the display board on the PDP in the display board system according to Embodiment 3 of the present invention; FIG. 41 shows an example of how the freehand characters and lines displayed on the screen of the display board are deleted with an eraser in the display board system according to Embodiment 3 of the present invention; FIG. 42 shows an example of how the freehand characters and lines displayed on the screen of the display board are enclosed with a box and the characters and lines in the box are deleted in one operation in the display board system according to Embodiment 3 of the present invention; FIG. 43 shows a line drawn on the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 44 shows a rectangle drawn on the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 45 shows a grid pattern displayed as a background of the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 46 shows a table created on the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 47 shows an ellipse created on the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 48A shows selection of a graphics as an object for modification and FIG. 48B shows the graphics after its modification in the display board system according to embodiment 3 of the present invention; FIG. 49A shows selection of a graphics as an object to be moved and FIG. 49B shows the graphics after its movement in the display board system according to Embodiment 3 of the present invention; FIG. 50 shows an example of a edit menu displayed when an already created graphics is to be edited in the display board system according to Embodiment 3 of the present invention; FIG. 51 shows the processing for opening an already generated file in the display board system according to Embodiment 3 of the present invention; FIG. 52 shows the processing for opening an already generated file using thumbnail images in the display board system according to Embodiment 3 of the present invention; FIG. 53 shows an example of a screen of the computer and a capture toolbar displayed on the PDP in the display board system according to Embodiment 3 of the present invention; FIG. 54 shows an example of how a screen of a captured application program is displayed as a background of the screen of the display board in the display board system according to Embodiment 3 of the present invention; FIG. 55 shows an example of how a screen of a captured application program is displayed as a background of the screen of the display board and how the characters or the like are written on the screen in the display board system according to Embodiment 3 of the present invention; FIG. 56 shows how a thumbnail display dialog box for displaying the pages in creation in a list form is displayed in the display board system according to Embodiment 3 of the present invention; FIG. 57 shows how a printing dialog box for printing the pages in creation is displayed in the display board system according to Embodiment 3 of the present invention; FIG. 58 shows an example of a setting screen for coordinate-position input device in the display board system according to Embodiment 3 of the present invention; FIG. 59 shows the network connection of the display board system according to Embodiment 3 of the present invention; FIG. 60 shows the configuration of a display unit of a display board system according to Embodiment 4 of the present invention; FIG. 61 is a block diagram showing a main control section of the display board system according to Embodiment 4 of the present invention; FIG. 62 shows a screen that displays a point-operation area in the display board system according to Embodiment 4 of the present invention; FIG. 63 is a flow chart of a point operation in the display board system according to Embodiment 4 of the present invention; FIGS. 64A, 64B and 64C are processing steps showing display and deletion of a point-operation area in the display board system according to Embodiment 4 of the present invention; FIG. 65 is a flow chart of the processing for display and deletion of a point-operation area in the display board system according to Embodiment 4 of the present invention; FIG. 66 is an explanatory view that shows display contents on the display screen appearing within the point-operation area in the display board system according to Embodiment 4 of the present invention; FIG. 67 shows a moving operation of the pointer in association with transformation of coordinates in the display board system according to Embodiment 4 of the present invention; FIG. 68 is a time chart showing drag operations according to operations within a point-operation area in the display board system according to Embodiment 4 of the present invention; FIG. 69 is a block diagram showing a first example of the configuration of a display board system according to Embodiment 5 of the present invention; FIG. 70 is an appearance view of the first example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 71 shows an example of a method of detecting a position of a person from an image based on the first example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 72 shows a method of deciding a position where a ten-key is to be displayed in the display board system according to Embodiment 5 of the present invention; FIG. 73 is a block diagram showing a second example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 74 is an appearance view showing the second example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 75 is a block diagram showing a third example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 76 is an appearance view showing the third example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 77 is a block diagram showing a fourth example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 78 is an appearance view showing the fourth example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 79 is a block diagram showing a fifth example of the configuration of the display board system according to Embodiment 5 of the present invention: FIG. 80 is an appearance view showing the fifth example of the configuration of the display board system according to Embodiment 5 of the present invention; FIG. 81 is a block diagram showing configuration, for displaying an input window (a ten-key display specifying window) to specify a position where a ten-key is displayed on an entry surface, applicable in the display board system according to Embodiment 5 of the present invention; FIG. 82 is a block diagram showing hardware configuration of the display board system according to Embodiment 5 of the present invention; FIG. 83 is a block diagram showing a first example of the configuration of a display board system according to Embodiment 6 of the present invention; FIG. 84 shows a waveform outputted from a coordinate-position input device in the first example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 85 is a flow chart of operations of the first example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 86 is a block diagram showing a second example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 87 is a flow chart of operations of the second example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 88 is a block diagram showing a third example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 89 is a flow chart of operations of the third example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 90 is a block diagram showing a fourth example of the configuration of the display board system according to Embodiment 6 of the present invention; and FIG. 91 is a block diagram showing a fifth example of the configuration of the display board system according to Embodiment 6 of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Detailed description is made hereinafter for embodiments of the a method and device for inputting/detecting the coordinate position according to the present invention and a display board system using the same with reference to the attached drawings. FIG. 1 is a front view showing general configuration of a coordinate-position inputting/detecting device according to Embodiment 1 of the present invention. FIG. 1 shows a state when the coordinate-position inputting/detecting device according to Embodiment 1 is attached to the front surface of a writing surface E (e.g., a white board) of a display board as an example. This coordinate-position inputting/detecting device 1 comprises a frame 1a having a rectangular space having substantially the same size as the writing surface E of a display board, namely having an entry area 2 where a user performs an entry operation using a pointing body such as a finger or a pen. Provided in this frame 1a are a lighting device 4, image pickup devices 7L and 7R, a shade 8, a light absorbing member 9, and a light receiving element 10. The pointing body may be anything such as a user's finger or hand, or a pen on the condition that an arbitrary position can be pointed therewith. The lighting device 4 is provided at substantially the center of the upper side of the entry area 2 and emits light which spreads in parallel with the writing surface E as well as over the entire entry area 2 using the light from a light source (Refer to FIG. 2). The entry area 2 in the coordinate-position inputting/detecting device 1 according to Embodiment 1 is actually formed with the light emitted from the lighting device 4 so as to cover the whole surface of the writing surface E. The image pickup devices 7L and 7R are provided at both edges of the upper side of the entry area 2 on the same side as that of the lighting device 4 and are separated from each other by a distance L. The image pickup devices 7L and 7R pick up an image of a pointing body inserted into the entry area 2. Each of the image pickup devices 7L and 7R have at least a CCD (Charge Coupled Device) 5 as a one-dimensional image sensor (one-dimensional image pickup element) for outputting image information (an image of an object) as an electric signal, and a focusing optical lens 6 for forming an image of the pointing body inserted into the entry area 2 on the CCD 5 as shown in FIG. 1. The CCD 5 and the focusing optical lens 6 are separated from each other by a distance f (Refer to FIG. 5). The shade 8 is provided on the lighting device 4 so that the light from the lighting device 4 can uniformly be emitted over the entire entry area 2. Further, the shade 8 also prevents the light emitted from the lighting device 4 to be directly entering into the image pickup devices 7L and 7R. The light absorbing member 9 is provided in the peripheral section of the entry area 2 except in the upper side thereof. This light absorbing member 9 suppresses reflection of the light by absorbing the light emitted from the lighting device 4. Namely, the light absorbing member 9 is provided in order to prevent the reflected light (scattered light) due to the light emitted from the lighting device 4 from its entering the image pickup devices 7L and 7R. Furthermore, the light receiving elements 10 (e.g., PIN photodiodes) are located on the light absorbing member 9 at both edges of the lower side of the entry area 2. These light receiving elements 10 receive the light emitted from the lighting device 4 and outputs a signal according to intensity of the received light. In the coordinate-position inputting/detecting device 1 according to Embodiment 1 as shown in FIG. 1, the lighting device 4 as well as the image pickup devices 7L and 7R are located along one line in the upper side of the entry area 2. Thus, the direction in which the light is emitted from the lighting device 4 is the same as that to which an object (pen A) is viewed from the image pickup devices 7L and 7R. As a result, the light emitted from the lighting device 4 can be prevented from directly entering into the image pickup devices 7L and 7R, and also production of a shadow on the pointing device viewed from the image pickup devices 7L and 7R can be prevented as much as possible. However, the lighting device 4 as well as the image pickup devices 7L and 7R may be located not in the upper side of the entry area 2 but, for instance, in the lower side thereof, therefore, FIG. 1 does not limit the location of the attachment of the lighting device 4 as well as of the image pickup devices 7L and 7R. When a pointing device such as a finger or a pen is inserted into the entry area 2, although detailed description will be made later, the light emitted from the lighting device 4 is irregularly reflected by the pointing device, and a portion of the irregularly reflected light is detected by each CCD 5 in the image pickup devices 7L and 7R respectively. In other words, the image pickup devices 7L and 7R in Embodiment 1 have sensitivity only when the pointing device is inserted into the entry area 2, and capture an image (pick up an image) of the pointing device inserted into the entry area 2 through the irregularly reflected light. By the way, in the description below, a state where a portion of the pointing device such as a finger and a pen contacts the writing surface E and moves along the writing surface E with the device contacted thereto will be called as a pen-down state. Comparing this pen-down state to a writing state with a fountain pen or a ball-point pen, the former state corresponds to a state where a tip of the pen contacts and ink oozes out from the pen tip. Then, a state where the pointing device moves in the vertical direction with respect to the writing surface E and there is no contact between the device and the writing surface E will be called as a pen-up state. Comparing the pen-up state to a writing state with a fountain pen or a ball-point pen, the former state corresponds to a state where a tip of the pen is moved away from a paper at intervals between strokes of characters or during movement between characters and the ink does not ooze out from the pen tip. Therefore, by enabling determination as to whether the pointing device is in a pen-up state or a pen-down state in the coordinate-position inputting/detecting device 1, it is possible to electronically imitate a writing operation such that characters and graphics are drawn on paper with a fountain pen or a ball-point pen. In the coordinate-position inputting/detecting device 1 according to Embodiment 1, when the writing surface E is viewed along the same direction as that of the image pickup devices 7L and 7R, it can clearly be understood that a layer of light having a certain thickness along the vertical direction of the writing surface E is formed because of the light emitted from the lighting device 4. Herein, the pen-up/pen-down state will be described assuming that light is emitted from the lighting device 4 very close to the writing surface E. When a pointing device is gradually being inserted into the entry area 2 the quantity of light reflected by the pointing device gradually increases. A pen-down state is a state where the pointing device penetrates through the entire layer of the light and contacts the writing surface E. In this pen-down state, the quantity of light reflected by the pointing device is the maximum. On the other hand, a pen-up state is a state where the pointing device is floating over the writing surface E, therefore, the quantity of light reflected by the pointing device is less as compared to that in the pen-down state. In other words, the area on the pointing device that is lighted because of the light emitted from the lighting device 4, namely, the area from where the light is reflected in the pen-up state is different from that in the pen-down state. In coordinate-position inputting/detecting device 1 according to Embodiment 1, it is possible to determine whether a pointing device is in the pen-up state or in the pen-down state according to the light quantity of the images of the pointing device picked up by the image pickup devices 7L and 7R. However, when the layer of the light is formed at a position which is separated from the writing surface E, change in the light quantity of the image of the pointing device in the pen-up state and pen-down state is difficult to occur in proportion to the distance from the writing surface E to the layer of the light. In other words, when there is a gap (a region of no light) between the writing surface E and the layer of the light an object can not be sensed. More specifically, even if the pointing device is in the state where the device does not contact the writing surface E (pen-up state), the same light quantity as that in the pen-down state may sometimes be obtained when the light layer is formed at the location away from the writing surface E, which may possibly be determined as the pen-down state. When a character string is written on the writing surface E in this state then all the movements of the pointing device are determined as the movements for the entry of characters. Due to this, a drawback in the input device that characters and words get linked to each other may occur. The above mentioned pen-up/pen-down state has to accurately be determined at any position on the writing surface E. Therefore, the height and parallelism of the light emitted from the lighting device 4 with respect to the writing surface E are required to precisely be adjusted. The configuration of the lighting device 4 will then be described more specifically. FIG. 2 shows a general configuration of the lighting device 4. As shown in FIG. 2, the light emitted from the light source 3 towards the writing surface E is transformed into parallel light by the optical lens 11. This parallel light is then passed through an arc-shaped slit 12 and is reflected by an inclined surface 13a of a conical mirror 13. When the light is reflected by the conical mirror 13, a light which is parallel to the writing surface E as well as which spreads over entire area of the entry area 2 is obtained. Herein, the conical mirror 13 will be described in more detail. FIG. 2 shows a cross section of the conical mirror 13. A shaft 14 is provided at the center of the conical mirror 13 as shown in FIG. 2. This shaft 14 is used not only for attachment of the conical mirror 13 to the frame 1a by being inserted into a hole (not shown) provided in the frame 1a, but also for adjustment of an angle at which light from the light source 3 is to be reflected. Provided at the end of the shaft 14 is a spherical angle adjusting section 15. By moving the angle adjusting section 15 to and fro and both sides, the angle of reflection of the light passing through the arc slit 12 can be changed in the X-Y direction, therefore, parallelism of the light with respect to the writing surface E can be adjusted. The angle adjusting section 15 is connected to an actuator 16 for adjusting the angle of reflection of the light by the conical mirror 13 by moving the angle adjusting section 15. The actuator 16 is driven under the control by a microcomputer (Refer to FIG. 3) described later according to light receiving power of the light receiving element 10 having received the light reflected by the conical mirror 13. Namely, the actuator 16 makes the angle adjusting section 15 operate under the control by the microcomputer to adjust the angle of reflection of the light by the conical mirror 13 so that the light receiving power of the light received by the light-receiving element 10 is the maximum (namely, so that the light reflected from the conical mirror 13 vertically enters the light receiving element 10). As described above, by automatically adjusting the reflecting angle of the light by the conical mirror 13, parallel light with respect to the writing surface E can be emitted from the lighting device 4. Therefore, it is possible to enhance detection precision of coordinates where a pointing body is positioned and also to accurately determine a pen-up/pen-down state. FIG. 3 is a block diagram of the coordinate-position inputting/detecting device 1 according to Embodiment 1. As shown in FIG. 3, the coordinate-position inputting/detecting device 1 has a microcomputer 17 which provides controls over all the sections of the device. This microcomputer 17 comprises a CPU 19 which provides a centralized control over all the sections of the device, a ROM 20 which stores therein fixed data such as a control program, and a RAM 21 which stores therein variable data. Connected to the microcomputer 17 are the above mentioned light source 3, image pickup devices 7L and 7R, light receiving element 10, actuator 16, and a timer 22 for counting a prespecified time, an xy computing unit 23 for computing coordinates of a position of a pointing body using images of the pointing body picked up by the image pickup devices 7L and 7R, and an interface (I/F) 18 for connecting the coordinate-position inputting/detecting device 1 to a computer (e.g., a personal computer) or the like each described later through a bus 28. A shadow correcting section 27 is provided to the xy computing unit 23 is for executing processing so that a shadow produced on the pointing body inserted into the entry area 2 will not cause any influence over the processing for identifying coordinates of a position of the pointing body. The RAM 21 has a coordinate memory 24 provided therein for temporarily storing the coordinates of a position of the identified pointing body in the manner as described later. Furthermore, a distortion correcting section 25 and a pattern recognizing section 26 are provided in the CCD 5. The distortion correcting section 25 electrically corrects difference in measurement due to optical distortion of image information obtained by the CCD 5. With this operation, higher quality of image information can be achieved. The pattern recognizing section 26 executes processing for recognizing a plurality of pointing bodies to make an entry operation possible to be performed by concurrently using the plurality of pointing bodies. For example, different specific patterns are given to the pointing bodies respectively, and the pattern recognizing section 26 recognizes and determines a pattern given to a pointing body trough the CCD 5. As a result, it is possible to compute coordinates of positions pointed by the plurality of pointing bodies respectively as described later. The processing executed by the microcomputer 17 according to the control program stored in the ROM 20 will be described. It should be noted that the processing for adjusting a reflecting angle of light by the conical mirror 13 is as described above, therefore, description is made herein for the processing executed by the microcomputer 17 centering on the processing for computing coordinates of a position of a pointing body such as a user's finger and a pen inserted into the entry area 2. FIG. 4 and FIG. 5 explain the processing for computing coordinates of a position of a pointing body inserted into the entry area 2. FIG. 4 shows a state where an arbitrary position within the entry area 2 is pointed to by a pen A as a pointing body, while FIG. 5 shows a portion of FIG. 4 enlarged to make clear a relation between the image pickup device 7L and the pen A. As shown in FIG. 4, when the pen A (pointing body) is inserted into the entry area 2 in order to write a character or a graphic at a certain position (x, y) on the writing surface E, the inserted pen A is illuminated by the light emitted from the lighting device 4. A subject image as an image of the portion of the illuminated pen A is formed on each of the CCD 5 through the focusing optical lens 6 of the image pickup devices 7L and 7R. The xy computing unit 23 shown in FIG. 3 executes the processing for computing coordinates (x, y) of a position of the pen A according to the subject images formed on the CCDs 5 as described above. Specific description is made for the processing of computing the coordinates (x, y) of a position of the pen A by the xy computing unit 23. Description is made herein for the processing of computing the coordinates (x, y) of the position of the pen A by taking the subject image picked up by the image pickup device 7L shown in FIG. 5 as an example. It should be noted that the processing described later is also executed to the subject image picked up by the image pickup device 7R. FIG. 6 is a graph showing an example of a relation between a position of a subject image formed on the CCD 5 of the image pickup device 7L and light quantity of the subject image picked up by the CCD 5. In FIG. 6, the position of the subject image formed on the CCD 5 is represented by a distance h from the center 5a of the CCD 5 to an imaging point. The subject image picked up by the CCD 5 appears as a waveform shown in FIG. 6 according to the position of the image formed on the CCD 5 as well as to the light quantity. Herein, assuming that a threshold level concerning the light quantity of the subject image is set to a level indicated by a dotted line in FIG. 6, a size .DELTA.h of the subject image can be computed with the following equation. Where h1 and h2 are distances from the center 5a of the CCD 5 to the position where the light quality at the same level as the threshold level is obtained as shown in FIG. 6. Then, the center h of the subject image shown in FIG. 6 (the distance h from the center 5a of the CCD 5 to a point at which the image is formed) can be computed with the following equation. As shown in FIG. 5, the distance h from the center 5a of the CCD 5 to the point at which the image is formed depends on the angle .theta. between a central line of the CCD 5 and a line linking the pen A and the point at which the image is formed. This angle .theta. can be computed by with the following equation. Where f is a distance between the focusing optical lens 6 and the CCD 5, which in turn corresponds to the focal length of the focusing optical lens 6. As shown in FIG. 5, an angle .beta. between the image pickup device 7L and the pen A can be computed with the following equation. Where .alpha. is an angle between a reference line that links the image pickup devices 7L and 7R and the central line of the CCD 5, this in turn is the angle at which the image pickup device 7L is attached. By executing the same above processing to the subject image picked up by the image pickup device 7R, an angle .beta. between the image pickup device 7R and the pen A can also be computed. Herein, the angle between the image pickup device 7L and the pen A will be considered to .beta.1 while the angle between the image pickup device 7R and the pen A will be considered as .beta.2 as shown in FIG. 4. Then, the coordinates (x, y) of the position of the pen A can be computed with the following equation based on the principle of triangulation. In addition, by monitoring the changes in the level of the light quantity of the subject image shown in FIG. 6, it is also possible to determine whether the state of the pen A is a pen-up/pen-down state or a double-clicked state or not. Although the coordinates (x, y) of the position of the pen A computed by the processing described above may be inputted into a computer through the I/F 18 as they are, by executing the processing for correction described below, coordinates (x, y) of a more accurate position of the pen A can be computed. The reason why execution of the correction processing is preferable is because a shadow S as shown in FIG. 7 is produced on the pen A viewed from the image pickup devices 7L and 7R (the cross section of the pen A in FIG. 7 is a circle). More specifically, as shown in FIG. 8, the size .DELTA.h' of the subject image of the pen A formed on the CCD 5 in a state when there is no shadow S thereon is larger than the size .DELTA.h (computed according to the Equation (1)) of the subject image of the pen A having the shadow S thereon. Therefore, when a shadow S is produced, an error occurs in the computation (according to Equation (2)) of the distance h from the center 5a of the CCD 5 to the point at which the image is formed and the coordinates of the computed position of the pen A are not accurate. Therefore, in order to compute accurate coordinates of a position, it is required to take into consideration existence of a shadow S on the pen A. A method of computing the accurate coordinates (x, y) of the position of the pen A is described by describing hereinafter a method of computing a distance h from the center 5a of the CCD 5 to a point at which the image is formed by taking into consideration existence of the shadow. At first, description is made for the processing of computing a width of an illuminated portion of the pen A by the light emitted from the lighting device 4, namely a width .DELTA.H of the subject shown in FIG. 7 according to the subject image of the pen A formed on the CCD 5 of the image pickup device 7L. In this case, a magnification of a subject image formed on the CCD 5 is considered to change according to a distance D (Refer to FIG. 5 and FIG. 7) between the image pickup devices 7L and 7R and the pen A. FIG. 9 is a graph showing an example of a relation between a position of a subject image formed on the CCD 5 of the image pickup device 7L, light quantity of the subject image picked up by the CCD 5, and the distance D. The difference in the magnification of the subject image formed on the CCD 5 appears due to the difference in the width of output from the CCD 5 as shown in FIG. 9. Namely, when the distance D is long the subject image becomes of a size as shown by the sign .DELTA.h, and when the distance D is short the subject image becomes of a size shown by the sign .DELTA.h'. This distance D is computed according to the coordinates (x, y) of the position of the pen A computed with the Equation (5) and Equation (6) as well as according to the angle .theta. computed with the Equation (3). Then, width of the illuminated portion of the pen A due to the light emitted from the lighting device 4, namely a subject width .DELTA.H of the pen A shown in FIG. 7 is computed with the following equation. It should be noted that this processing may be executed by either the xy computing unit 23 or the shadow correcting section 27. Then, the shadow correcting section 27 executes the processing for correcting the center h of the subject image (a distance h between the center 5a of the CCD 5 and the point at which the image is formed) according to, for instance, the subject image width .DELTA.H' of the actual pen A previously stored in the ROM 20 together with the control program. As shown in FIG. 8, assuming that the center of the corrected subject image is h', the center h' can be computed with the following equation as an approximate value. The subject image width .DELTA.H of the pen A shown in FIG. 7 can be computed by using the following Equation (7') in place of the Equation (7). In this case, an angle .gamma. between a straight line which links the light source 3 and the subject (pen A) and a straight line which links the center h of the subject image obtained with Equation (2) and the subject (pen A) is computed. Then, by substituting this angle .gamma. and the subject width .DELTA.H' of the actual pen A previously stored in the ROM 20 in the Equation (7'), a subject width .DELTA.H of the pen A viewed from the center h of the subject image on the CCD 5 can be computed. Then, by substituting the computed value in Equation (8), center h' of the subject image can be obtained. In case of the image pickup device 7R also, a width .DELTA.H of a subject can be computed in the same manner as described above, and the processing of computing the center h' of the subject image is executed. Then, the xy computing unit 23 executes again the processing of computing the coordinates (x, y) of a position of the pen A using the value of the center h' obtained in the shadow correcting section 27. Namely, the xy computing unit 23 executes the sequence of calculation described with respect to Equation (3) to Equation (6) using the value of the center h' obtained in the shadow correcting section 27, and computes the coordinates of the position of the pen A. As a result, it is possible to compute the coordinates of the accurate position. Although data for a subject width .DELTA.H' of the pen A used in the coordinate-position inputting/detecting device 1 is previously stored in the ROM 20 herein as one example, rewriting data as required may be possible by storing a subject width .DELTA.H' in a memory such as a non-volatile RAM so that a pen to be used can be changed. The above mentioned Equations (1) to (8) can previously be stored in the ROM 20 as a portion of the control program. The coordinates (x, y) of a position of a pen A are computed according to a distance h between the center 5a of the CCD 5 and the subject image formed on the CCD 5 through those Equations (1) to (8). Namely, by computing a distance h from the center 5a of the CCD 5 in the image pickup device 7L as well as a distance h from the center 5a of the CCD 5 in the image pickup device 7R, the coordinates (x, y) of a position of the pen A can be obtained. Furthermore, the subject image of a pen A does not always have to perfectly be formed on the CCD 5. Namely, when the image is not perfectly formed thereon, only the size .DELTA.H of the subject image on the CCD 5 becomes larger, therefore, the center h' of the subject image is not affected thereby. The coordinates (x, y) of the position of the pen A computed as described above are temporarily stored in the coordinate memory 24 and then inputted into a computer through the I/F 18. The coordinates of a position mentioned herein indicate either one of the coordinates having been subjected to correction because of the above mentioned shadow or the coordinates which are not subjected to any correction. FIG. 10 is a flow chart showing the processing when coordinates of a computed position are transferred to a computer. The microcomputer 17 makes, as shown in FIG. 10, when the coordinates (x2, y2) of the position of the pen A are computed by the xy computing unit 23, namely when the pen-down state is detected (Yes in step S1), the timer 22 start counting a prespecified time (step S2). In the next step, the microcomputer 17 determines whether the coordinates (x2, y2) of the computed position are coincident with the coordinates (x1, y1) of the position stored in the coordinate memory 24 or not (step S3). When it is determined that the coordinates of the two positions are not coincident (No in step S3), the microcomputer 17 updates the coordinates of the position stored in the coordinate memory 24 to the newly computed coordinates (x2, y2) of the position, and clears the counting by the timer 22 (step S4). Then, the microcomputer 17 transfers the coordinates of the position in the coordinate memory 24 to a computer (step S5), the system control is returned to step S1 where the microcomputer waits for a new detection of a pen-down. The computer executes the processing in response to movement of the pen A according to the transferred coordinates of the position. For example, the computer executes the processing for drawing characters and graphics on a display. On the other hand, when it is determined that the coordinates of the two positions are coincident (Yes in step S3), the microcomputer 17 waits for computation of coordinates of a new position which are different from the coordinates of the position stored in the coordinate memory 24 by the xy computing unit 23 during the period of time until a prespecified time is counted by the timer (step S6, step S7, step S3). More specifically, the microcomputer 17 waits for computation of the coordinates of a new position by the xy computing unit 23 (detection of the pen-down state), and when the coordinates of the new position are computed (Yes in step S7), the system control is shifted to step S3, and the microcomputer 17 determines whether the coordinates of the computed position is coincident with the coordinates of the position in the coordinates memory 24 or not. Then, when it in determined that the coordinates of the two positions are not coincident (No in step S3), the microcomputer 17 executes the processing in steps S4 and step S5 as described above. On the other hand, when it is determined that the coordinates of the two positions are coincident (Yes in step S3), the microcomputer 17 shifts the system control again to step S6. Then, the microcomputer 17 executes, when it is determined that the prespecified time has passed (Yes in step S6), the error processing (step S8), returns the system control to step S1, and waits for new detection of a pen-down. Namely, when non coincident coordinates can be obtained (step S3) until the prespecified time passes, it is considered that there is no movement of the pen A. Therefore, the coordinates of the computed position by the xy computing unit 23 are regarded as a position of, for instance, dust or something deposited on the writing surface E, and the error processing is executed in step S8. As this error processing, the microcomputer 17 does not update the coordinates (x1, y1) of the position stored in the coordinates memory 24, but discards the coordinates (x2, y2) of the position computed in step S1 so that the coordinates of the position in the coordinates memory 24 will not be transferred to the computer. In this case, the microcomputer 17 may provide controls for transmitting an error signal to the computer to stop an entry operation of coordinates and then restarting, when the dust or something is removed and an instruction for restoration is inputted by the user, the stopped operation of entering coordinates. The microcomputer 17 may transfer the coordinates of the position of the dust-like substance to the computer and give a note on the dust-deposited position to the computer. With this configuration, the coordinates of the position of the dust can be prevented from being entered into the computer. Furthermore, in the coordinate-position inputting/detecting device 1 according to Embodiment 1, a plurality of users can also concurrently enter freehand characters and graphics into a computer. In this case, however, each of the pointing bodies to be used at the same time needs to be discriminated from the others. In the coordinate-position inputting/detecting device 1 according to Embodiment 1, the pattern recognizing section 26 shown in FIG. 3 performs the processing of identifying the plurality of pointing bodies, and the xy computing unit 23 computes coordinates of a position for each identified pointing body. For example, it is assumed that pointing bodies are pens and each of patterns with differently-pitched stripes is added to the periphery of each pen (the pattern may be anything such as vertical stripes, horizontal stripes or a grid). The pattern recognizing section 26 executes the processing for recognizing patterns of the plurality of pens picked up by the CCD 5 in each of the image pickup devices 7L and 7R. FIG. 11 explains the processing when an operation of inputting freehand characters and graphics into a computer is performed concurrently using two pens. Herein, it is assumed as an example that 'a' point a and a point 'b' in the entry area 2 are concurrently pointed to by using two pens. In this case, subject images of the pens existing in the directions of 1 and 2 are picked up by the image pickup device 7L, while subject images of the pens existing in the directions of 3 and 4 are picked up by the image pickup device 7R respectively. Herein, if identification can not be made which subject images are of the same pen among the subject images of the pens picked up by the image pickup devices 7L and 7R, coordinates of a point 'c' and a point 'd' will be computed in addition to those of the point 'a' and point 'b'. Therefore, it is necessary to identify which subject images are of the same pen by using differently pitched patterns added to the periphery of pens. However, a pitch of each pattern of the subject images picked up by the image pickup devices 7L and 7R changes according to a distance D between the image pickup devices 7L and 7R and the pen even if the pitches are the same (Refer to FIG. 9). Therefore, the coordinates of all positions of the points 'a' to 'd' will be computed hereinafter. As described above, by computing the coordinates of positions of the points 'a' to 'd', each distance D between the image pickup device 7L and each point from the points 'a' to 'd' can be computed respectively, and also each distance D between the image pickup device 7R and each point from the points 'a' to 'd' can be computed respectively. Then, the microcomputer 17 computes, assuming that an actual pitch of a pattern added to a pen is P and a pitch of each pattern among the subject images changing according to each distance from the image pickup devices 7L and 7R to a pen is p (which is recognized by the pattern recognizing section 26), each pattern pitch of pens at each point using the equation described below. By using the above equation, each pitch P of pens at each point from the points 'a' to 'd' viewed from the image pickup device 7L is computed, and also each pitch P of pens at each point from the points 'a' to 'd' viewed from the image pickup device 7R is computed respectively. Then, the microcomputer 17 compares each pitch P of pens at each point from the points 'a' to 'd' viewed from the image pickup device 7L to each pitch P of pens at each point from the points 'a' to 'd' viewed from the image pickup device 7R respectively, and determines that the points whose pitches P are coincident or similar are points that are actually pointed by pens. The method of enabling identification of each pointing body is not limited to the above mentioned patterns, but there are also methods of changing a color for each pointing body (this will require a use of a color CCD as the CCD 5) or of changing a form and a size or the like of each pointing body. As described above, with the coordinate-position inputting/detecting device 1 according to Embodiment 1, the lighting device 4 emits light to the entry area 2, a pointing body illuminated by the light emitted from the lighting device 4 is picked up by at least two image pickup devices 7L and 7R, each position on the CCD 5 where an image of the pointing body is formed is computed according to each output from the image pickup devices 7L and 7R respectively, coordinates of position of the pointing body is computed by using the computed position, so that coordinates of a position in the entry area pointed using an arbitrary pointing body such as a finger tip or an ordinary pen can be identified, which allows operability of the coordinate-position inputting/detecting device to be enhanced. In the coordinate-position inputting/detecting device 1 according to Embodiment 1, although measures are taken so that light does not directly enter the image pickup devices 7L and 7R by providing the shade 8 on the lighting device 4, the same measures may be taken using some technique other than using the shade 8. The area into which the light is to be emitted may be restricted by the lighting device 4 itself. In the coordinate-position inputting/detecting device 1 according to Embodiment 1, although the light absorbing member 9 for suppressing reflection of light is provided on the peripheral section of the entry area 2 excluding the upper side thereof, creating a perfect non-reflecting condition described above is not an essential condition for the present invention. For example, in place of the light absorbing member 9, a reflecting member having a uniform reflecting condition in a direction to which light is diverted away from the entry area 2 may be provided on the peripheral section of the entry area 2 excluding the upper side thereof. As a result, the light emitted from the lighting device 4 is reflected by the reflecting member toward outside of the entry area 2, therefore, the reflected light (scattered light) can be prevented from entering into the image pickup devices 7L and 7R. In the coordinate-position inputting/detecting device 1 according to Embodiment 1, although the lighting device 4 is used, coordinates of a position of a pointing body can be computed by picking up an image of the pointing body inserted into the entry area 2 by the image pickup devices 7L and 7R even if the lighting device 4 is omitted therefrom. That is because the coordinate-position inputting/detecting device 1 according to Embodiment 1 computes coordinates of a position of a pointing body using each position of images of the pointing body formed on the CCDs 5 of the image pickup devices 7L and 7R. As an example, FIG. 12 shows a front view of a general configuration of the coordinate-position inputting/detecting device 1 from which the lighting device 4 is omitted. As shown in FIG. 12, when the lighting device 4 is omitted from the coordinate-position inputting/detecting device 1, the shade 8, the light absorbing member 9, and the light receiving element 10 can also be omitted therefrom in accordance with the above case. Furthermore, by using a frame of a display board, the coordinate-position inputting/detecting device 1 according to Embodiment 1 can be integrated with the display board. In addition, the coordinate-position inputting/detecting device 1 according to Embodiment 1 can be used by attaching to the front surface of the display of a computer, and the coordinate-position inputting/detecting device 1 according to Embodiment 1 can also be integrated with the display by using the frame of the display. FIG. 13 is a front view showing a general configuration of a coordinate-position inputting/detecting device according to Embodiment 2 of the present invention. FIG. 13 shows a state, as an example, where the coordinate-position inputting/detecting device 31 according to Embodiment 2 is attached to a display surface d of a computer. The coordinate-position inputting/detecting device 31 has a frame 32 having a rectangular space with substantially the same size as that of the display surface d of a computer, namely having an entry area 33 for performing an entry operation using a pointing body such as a finger or a pen by a user. Provided on this frame 32 are cameras 34L and 34R and a background plate 37 which will be described in detail below. The cameras 34L and 34R are provided on both edges in the upper side of the entry area 33 at a distance L therebetween. The cameras 34L and 34R pick up an image of the entry area 33 and output the image (photographed image) as an electric signal. These cameras 34L and 34R are electronic cameras, and each of the cameras has a two-dimensional image sensor (two-dimensional image pickup element) 35 and a focusing optical lens 36. This two-dimensional image sensor 35 is a two-dimensional CCD image pickup element formed with a large number of CCDs (Charge Coupled Device) arranged in a matrix. The two-dimensional image sensor 35 and focusing optical lens 36 are spaced at a distance f therebetween. In addition, the cameras 34L and 34R are located so that each optical axis of the cameras is parallel with the display surface d and at substantially the same level as that of the surface of the display surface d. Because of this configuration, the display surface d can be prevented from its reflection into the cameras 34L and 34R. The background plate 37 is provided at a location as a peripheral section of the entry area 33 excluding the upper side thereof where the whole field of view photographed by the cameras 34L and 34R is covered. The background plate 37 is located so as not to interrupt with the angle of view of the cameras 34L and 34R. FIG. 14 explains the background plate 37 and shows a portion of the background plate 37. As shown in FIG. 14, a reference pattern P for making easier extraction of a differential image described later is added to the background plate 37. The reference pattern P shown in FIG. 14 is a pattern with horizontal stripes in dark and light colors, but color patterns or the like used in chroma key technology can also be used as the reference pattern P. Furthermore, a pattern in uniform black color which absorbs the light may be used as a reference pattern on the background plate 37. In addition, a light shielding plate B for restricting an area to be photographed is attached to each of the cameras 34L and 34R. FIG. 15 explains the light shielding plate B, and FIG. 16 is a cross-sectional view of the coordinate-position inputting/detecting device 31. As shown in FIG. 15, the light shielding plate B has a horizontal notch B1. Then, as shown in FIG. 16, the light shielding plates B are provided in the front surface of the focusing optical lenses 36 of the cameras 34L and 34R respectively, the area which can be photographed by each of the cameras 34L and 34R so restricted that the area matches the entry area 33. It is possible to reduce occurrence of noise due to disturbance light or the like by making the field of view of each of the cameras 34L and 34R narrow with this light shielding plate B. FIG. 17 is a block diagram of the coordinate-position inputting/detecting device 31 according to Embodiment 2. As shown in FIG. 17, the coordinate-position inputting/detecting device 31 has a microcomputer 38 which provides controls over all the sections of the device. This microcomputer 38 comprises a CPU 40 which provides centralized control over all the sections of the device, a ROM 41 which stores therein fixed data such as a control program, and a RAM 42 which stores therein variable data. Connected to the microcomputer 38 are, in addition to the above mentioned cameras 34L and 34R, a timer 43 for counting a prespecified time, a differential unit 44 for executing the processing of extracting an image of a pointing body as described later, an xyz computing unit 45 for computing coordinates of a three-dimensional position of a pointing body, and an interface (I/F) 39 for connecting the coordinate-position inputting/detecting device 31 to a computer (e.g., a personal computer) through a bus 51. Further connected to the microcomputer 38 through the bus 51 is an EEPROM 46 as a non-volatile memory. Provided in the EEPROM 46 is a reference image memory 47 for storing therein images, for instance, of a state of the entry area 33 on starting of the device photographed by the cameras 34L and 34R as reference images (Refer to FIG. 21). Provided in the RAM 42 is a coordinate memory 42a for temporarily storing therein coordinates computed by the xyz computing unit 45. Then, description is made for the processing executed by the microcomputer 38 according to the control program stored in the ROM 41. FIG. 18 and FIG. 19 explain the processing for computing coordinates of a position of a pointing body inserted into the entry area 33. FIG. 18 shows a state where an arbitrary position within the entry area 33 is pointed by a finger C as a pointing body, and FIG. 19 shows a portion of FIG. 18 enlarged to make clear a relation between the camera 34L and the finger C. As shown in FIG. 18, it is assumed that the finger C is inserted into the entry area 33 of the coordinate-position inputting/detecting device 31 and an arbitrary position (x, y, z) on the display surface d is pointed or touched thereby. Images of the background plate 37 and the finger C are formed on each two-dimensional image sensor 35 of the cameras 34L and 34R through each focusing optical lens 36. As shown in FIG. 20, the images of the background plate 37 and the finger C formed on the two-dimensional image sensors 35 are outputted from the two-dimensional image sensors 35 as photographed images 48. The photographed images 48 outputted from the two-dimensional image sensors 35 of the cameras 34L and 34R and reference images 49 stored in the reference image memories 47 are inputted into the differential units 44, and differential images 50 are extracted respectively. FIG. 21 is an explanatory view showing an example of the reference image 49, and FIG. 22 is an explanatory view showing an example of the photographed image 48. The reference image 49 shows the entry area 33 photographed by the cameras 34L and 34R in an initial state such as on starting of the device. Namely, the reference image 49 is the one with only the reference pattern P of the background plate 37 photographed as shown in FIG. 21. While the photographed image 48 is the one with the finger C having been inserted into the entry area 33 photographed in addition to the image of the reference image 49 as shown in FIG. 22. FIG. 23 is an explanatory view showing an example of a differential image extracted by the differential unit 44. The differential image 50 is a silhouette image consisting of black and white pixels obtained through processing of subtracting the reference image 49 (FIG. 21) from the photographed image 48 (FIG. 22) and setting a pixel brighter than a prespecified threshold value to white and a pi |