Coordinate input apparatus and method, and computer-readable memory therefor

• US 6,714,310 B1
• Filed: 09/05/2000
• Issued: 03/30/2004
• Est. Priority Date: 09/06/1999
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Kobayashi, Katsuyuki, Kobayashi, Kiwamu, Hasegawa, Masahide, Kanashiki, Masaaki, Yoshimura, Yuichiro
• Primary Examiner(s): Smith, Zandra V.
• Assistant Examiner(s): Stock, Jr., Gordon J
• Application Number:
  US09/655,775
• Time in Patent Office: 1,302 Days
• Field of Search: 356/614, 356/3.02, 356/3.01, 356/3.1, 250/216, 250/227.13, 345/156, 345/179, 345/182, 345/183, 345/180, 178/18.01, 178/18.02
• US Class Current: 356/614
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• 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 plurality of linear sensors (20Xa, 20Xb, 20Ya, 20Yb) sense a beam spot and the results of sensing the beam spot are corrected. The corrected items of data are concatenated and coordinates corresponding to the beam spot are calculated by a coordinate calculation unit (32) based upon the concatenated data. Light-receptive areas of the linear sensors (20Xa, 20Xb, 20Ya, 20Yb) have mutually overlapping portions.

Claims

1. A coordinate input apparatus in which light from a designating tool is applied to a prescribed position on a coordinate input screen to produce a light spot and coordinates corresponding to the light spot are generated, the apparatus comprising:

a plurality of sensing means, arranged in one coordinate axis, for sensing the light spot;

correction means for correcting results of sensing from each of said plurality of sensing means;

concatenation means for concatenating data that has been corrected by said correction means; and

output means for outputting coordinate values corresponding to the light spot based upon the data concatenated by said concatenation means;

wherein portions of areas from which said plurality of sensing means sense light overlap,

wherein said plurality of sensing means comprises first sensing means and second sensing means, and wherein said correction means corrects the results of sensing from each of said plurality of sensing means based upon inclination of said second sensing means relative to said first sensing means.

2. The apparatus according to claim 1, wherein said correction means corrects the results of sensing from each of said plurality of sensing means based upon reference coordinate values that have been stored in advance.

3. The apparatus according to claim 1, wherein each of said plurality of sensing means is a linear sensor comprising a plurality of optoelectronic transducers arrayed on a straight line.

4. The apparatus according to claim 1, wherein said correction means corrects the results of sensing from each of said plurality of sensing means based upon a magnification, which is for calculating coordinates, set for each of said plurality of sensing means.

5. The apparatus according to claim 1, wherein each sensing means of said plurality of sensing means is a sensor comprising a substantially linear array of pixels.

6. A coordinate input method in which light from a designating tool is applied to a prescribed position on a coordinate input screen to produce a light spot and coordinates corresponding to the light spot are generated, the method comprising:

a correction step of correcting results of sensing from each of a plurality of sensing units, arranged in one coordinate axis, for sensing the light spot;

a concatenation step of concatenating data that has been corrected at said correction step; and

an output step of outputting coordinate values corresponding to the light spot based upon the data concatenated at said concatenation step;

wherein portions of areas from which the plurality of sensing units receive light overlap,

wherein said correction step corrects the results of sensing from each of the plurality of sensing units based upon inclination of a second sensing unit relative to a first sensing unit among the plurality of sensing units.

7. The method according to claim 6, wherein said correction step corrects the results of sensing from each of the plurality of sensing units based upon reference coordinate values that have been stored in advance.

8. The method according to claim 6, wherein each of the plurality of sensing units is a linear sensor comprising a plurality of optoelectronic transducers arrayed on a straight line.

9. The method according to claim 6, wherein said correction step corrects the results of sensing from each of the plurality of sensing units based upon a magnification, which is for calculating coordinates, set for each of the plurality of sensing units.

10. A computer-readable memory storing coordinate-input program code for performing a method in which light from a designating tool is applied to a prescribed position on a coordinate input screen to produce a light spot and coordinates corresponding to the light spot are generated, said program code comprising:

program code of a correction step of correcting results of sensing from each of a plurality of sensing units, arranged in one coordinate axis, for sensing the light spot;

program code of a concatenation step of concatenating data that has been corrected at the correction step; and

program code of an output step of outputting coordinate values corresponding to the light spot based upon the data concatenated at the concatenation step;

wherein portions of areas from which the plurality of sensing units receive light overlap,

wherein said program code of a correction step corrects the results of sensing from each of the plurality of sensing units based upon inclination of a second sensing unit relative to a first sensing unit among the plurality of sensing units.