Coordinate input device and its control method, and computer readable memory

• US 6,847,356 B1
• Filed: 08/09/2000
• Issued: 01/25/2005
• Est. Priority Date: 08/13/1999
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Kanashiki, Masaaki, Yoshimura, Yuichiro, Kobayashi, Katsuyuki, Kobayashi, Kiwamu, Hasegawa, Masahide
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): NGUYEN, HAU H
• Application Number:
  US09/635,353
• Time in Patent Office: 1,630 Days
• Field of Search: 345/176, 345/166, 345/175, 345/157, 345/158, 345/180, 345/183, 345/179, 345/181, 345/182, 345/207, 356/375, 178/18.01, 178/18.09
• US Class Current: 345/176
• CPC Class Codes: G06F 3/03542 Light pens for emitting or receiving light
• CPC Class Codes: G06F 3/0386 for light pen
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

A device has a projection type image display unit which has a projection lens and generates a coordinate input screen, and linear sensors for sensing an image of a beam spot, and computes a coordinate value corresponding to the beam spot on the basis of information obtained by the projection type image display unit and the output signals from the linear sensors. This beam spot is generated by irradiating the predetermined position on the coordinate input screen with light coming from a pointing tool, or corresponds to a light-emitting portion provided to the distal end of the pointing tool located near the coordinate input screen.

Claims

1. A coordinate input device for generating a coordinate value corresponding to a light spot which is generated by irradiating a predetermined position of a coordinate input screen with light coming from a pointing tool or corresponds to a light-emitting portion provided at a distal end of the pointing tool located near the coordinate input screen, comprising:

an image display unit, having an optical system, for generating the coordinate input screen;

image sensing means for sensing an image of the light spot;

adjusting means for performing enlargement for a coordinate input screen image by adjusting a field angle of the optical system;

detection means for detecting a field angle correction state of the optical system of said image display unit on the basis of an adjustment amount by said adjusting means, and outputting correction information; and

coordinate operation means for operating a coordinate value corresponding to the light spot on the basis of the correction information and an output signal from said image sensing means.

2. The device according to claim 1, wherein the correction information indicates a setting state of an optical system of said image display unit.

3. The device according to claim 1, wherein the correction information indicates an image state of an image displayed by said image display unit.

4. The device according to claim 1, wherein said image sensing means comprises first image sensing means, constructed by a first sensor on a first coordinate axis, for sensing the image of the light spot, and second image sensing means, constructed by a second sensor on a second coordinate axis, for sensing the image of the light spot, and

the first and second coordinate axes are perpendicular to each other, and at least one of the first and second sensors is set with a predetermined direction and position on the coordinate axis thereof substantially agreeing with an optical axis of the optical system.

5. A method of controlling a coordinate input device for generating a coordinate value corresponding to a light spot which is generated by irradiating a predetermined position of a coordinate input screen with light coming from a pointing tool or corresponds to a light-emitting portion provided at a distal end of the pointing tool located near the coordinate input screen, comprising:

an image displaying step of, in an image display unit having an optical system, generating the coordinate input screen;

an image sensing step of sensing an image of the light spot using an image sensing unit;

an adjusting step of performing enlargement for a coordinate input screen image;

a detecting step of detecting a field angle correction state of the optical system of the image display unit on the basis of an adjustment amount from said adjusting step, and outputting correction information; and

a coordinate operation step of operating a coordinate value corresponding to the light spot on the basis of the correction information and an output signal from the image sensing unit.

6. The method according to claim 5, wherein the correction information indicates a setting state of an optical system of the image display unit.

7. The method according to claim 5, wherein the correction information indicates an image state of an image displayed by the image display unit.

8. The method according to claim 5, wherein the image sensing unit comprises first image sensing means, constructed by a first sensor on a first coordinate axis, for sensing the image of the light spot, and second image sensing means, constructed by a second sensor on a second coordinate axis, for sensing the image of the light spot, and

the first and second coordinate axes are perpendicular to each other, and at least one of the first and second sensors is set with a predetermined direction and position on the coordinate axis thereof substantially agreeing with an optical axis of the optical system.

9. A computer-readable memory that stores a program for controlling a coordinate input device for generating a light spot by irradiating a predetermined position of a coordinate input screen with light coming from a pointing tool, and generating a coordinate value corresponding to the light spot, comprising:

program code of an image displaying step for, in an image display unit having an optical system, generating the coordinate input screen;

program code of an image sensing step of sensing an image of the light spot using an image sensing unit;

program code of an adjusting step of performing enlargement for a coordinate input screen image;

program code of a detecting step of detecting a field angle correction state of the optical system of the image display unit on the basis of an adjustment amount from said adjusting step, and outputting correction information; and

program code of a coordinate operation step of operating a coordinate value corresponding to the light spot on the basis of the correction information and an output signal from the image sensing unit.

10. A coordinate input device which comprises a projection-type image display unit, a pointing tool which generates a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of said projection-type image display unit or has at a distal end thereof a light-emitting portion that serves as a light spot when said pointing tool is located near a coordinate input screen, and image sensing means for sensing an image of the light spot, comprising:

adjusting means for performing enlargement for a coordinate input screen image;

detection means for detecting a field angle correction state of a projection optical system of said projection-type image display unit on the basis of an adjustment amount by said adjusting means, and outputting correction information; and

coordinate operation means for generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by said image sensing means using the correction information output from said detection means.

11. The device according to claim 10, wherein said image sensing means has a pair of sensors for respectively detecting coordinates in two orthogonal X- and Y-axis directions, and

at least one axial direction of the pair of sensors is set to substantially agree with an optical axis of a projection lens of said projection-type image display unit.

12. The device according to claim 11, wherein each of the pair of sensors has a sensor array in which a plurality of photoelectric conversion sensors are arranged linearly, and

integrating means which includes charge transfer blocks coupled in a ring pattern, and independently integrates and holds output charges from each sensor as signals at ON and OFF timings in synchronism with a predetermined cycle time, and

said coordinate operation means makes a coordinate operation by converting a difference between ON and OFF signals in said integrating means into digital data with a data width of not less than n bits, and outputs a coordinate value having a resolving power approximately 2ⁿ times the number of pixels of the sensor array.

13. A coordinate input device which comprises a projection-type image display unit, a pointing tool which generates a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of said projection-type image display unit or has at a distal end thereof a light-emitting portion that serves as a light spot when said pointing tool is located near a coordinate input screen, and image sensing means for sensing an image of the light spot, comprising:

adjusting means for performing enlargement for a coordinate input screen image by adjusting a field angle of said projection-type image display unit, and outputting screen correction information of a size of a displayed image of said projection-type image display unit; and

coordinate operation means for generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by image sensing means using the screen correction information.

14. The device according to claim 13, wherein said image sensing means has a pair of sensors for respectively detecting coordinates in two orthogonal X- and Y-axis directions, and

at least one axial direction of the pair of sensors is set to substantially agree with an optical axis of a protection lens of said projection-type image display unit.

15. The device according to claim 14, wherein each of the pair of sensors has a sensor array in which a plurality of photoelectric conversion sensors are arranged linearly, and

integrating means which includes charge transfer blocks coupled in a ring pattern, and independently integrates and holds output charges from each sensor as signals at ON and OFF timings in synchronism with a predetermined cycle time, and

said coordinate operation means makes a coordinate operation by converting a difference between ON and OFF signals in said integrating means into digital data with a data width of not less than n bits, and outputs a coordinate value having a resolving power approximately 2ⁿ times the number of pixels of the sensor array.

16. A method of controlling a coordinate input device which comprises a projection-type image display unit, a pointing tool which generates a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of the projection-type image display unit or has at a distal end thereof a light-emitting portion that serves as a light spot when the pointing tool is located near a coordinate input screen, and an image sensing unit for sensing an image of the light spot, comprising:

an adjusting step of performing enlargement shift for a coordinate input screen image;

a detection step of detecting a field angle correction state of a projection optical system of the projection-type image display unit on the basis of an adjustment amount from said adjusting step, and outputting correction information of a size of a displayed image of the projection-type image display unit; and

a coordinate operation step of generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by the image sensing unit using the correction information output from said detection step.

17. The method according to claim 16, wherein the image sensing unit has a pair of sensors for respectively detecting coordinates in two orthogonal X- and Y-axis directions, and

at least one axial direction of the pair of sensors is set to substantially agree with an optical axis of a projection lens of the projection-type image display unit.

18. The method according to claim 17, wherein each of the pair of sensors has a sensor array in which a plurality of photoelectric conversion sensors are arranged linearly, and

integrating means which includes charge transfer blocks coupled in a ring pattern, and independently integrates and holds output charges from each sensor as signals at ON and OFF timings in synchronism with a predetermined cycle time, and

the coordinate operation unit makes a coordinate operation by converting a difference between ON and OFF signals in the integrating means into digital data with a data width of not less than n bits, and outputs a coordinate value having a resolving power approximately 2ⁿ times the number of pixels of the sensor array.

19. A method of controlling a coordinate input device which comprises a projection-type image display unit, a pointing tool which generates a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of the projection-type image display unit or has at a distal end thereof a light-emitting portion that serves as a light spot when said pointing tool is located near a coordinate input screen, and an image sensing unit for sensing an image of the light spot, comprising:

an adjusting step of performing enlargement for a coordinate input screen image by adjusting a field angle of the projection-type image display unit, and outputting screen correction information of a size of a displayed image of the projection-type image display unit; and

a coordinate operation step of generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by the image sensing unit using the screen correction information.

20. The method according to claim 19, wherein the image sensing unit has a pair of sensors for respectively detecting coordinates in two orthogonal X- and Y-axis directions, and

at least one axial direction of the pair of sensors is set to substantially agree with an optical axis of a projection lens of the projection-type image display unit.

21. The method according to claim 20, wherein each of the pair of sensors has a sensor array in which a plurality of photoelectric conversion sensors are arranged linearly, and

integrating means which includes charge transfer blocks coupled in a ring pattern, and independently integrates and holds output charges from each sensor as signals at ON and OFF timings in synchronism with a predetermined cycle time, and

the coordinate operation unit makes a coordinate operation by converting a difference between ON and OFF signals in the integrating means into digital data with a data width of not less than n bits, and outputs a coordinate value having a resolving power approximately 2ⁿ times the number of pixels of the sensor array.

22. A computer-readable memory that stores program code for controlling a coordinate input device which comprises a projection-type image display unit, a pointing tool for generating a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of the projection-type image display unit, and an image sensing unit for sensing an image of the light spot, comprising:

program code of an adjusting step of performing enlargement for a coordinate input screen image;

program code of a detection step of detecting a field angle correction state of a projection optical system of the projection-type image display unit on a basis of an adjustment amount from said adjusting step, and outputting correction information of a size of a displayed image of the projection-type image display unit; and

program code of a coordinate operation step of generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by the image sensing unit using the correction information output from said detection step.

23. A computer-readable memory that stores program code for controlling a coordinate input device which comprises a projection-type image display unit, a pointing tool which generates a light spot at an arbitrary position within a predetermined coordinate input region including an image display region of the projection-type image display unit or has at a distal end thereof a light-emitting portion that serves as a light spot when the pointing tool is located near a coordinate input screen, and an image sensing unit for sensing an image of the light spot, comprising:

program code of an adjusting step of performing enlargement shift for a coordinate input screen image by adjusting a field angle of the projection-type image display unit, and outputting screen correction information of a size of a displayed image of the projection-type image display unit; and

program code of a coordinate operation step of generating a coordinate output signal corresponding to a position of the light spot within the coordinate input region on the basis of a signal sensed by the image sensing unit using the screen correction information.