Coordinate input apparatus, its control method, and program

• US 20050200612A1
• Filed: 03/09/2005
• Published: 09/15/2005
• Est. Priority Date: 03/11/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Sato, Hajime, Kobayashi, Katsuyuki, Kobayashi, Kiwamu, Hasegawa, Masahide, Yoshimura, Yuichiro
• Granted Patent: US 7,443,387 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A signal change range, which is generated due to a pointing operation of a pointer on a coordinate input region, with respect to an initial detection signal distribution of a detection unit in an initial state in which no pointing operation is made on the coordinate input region, is specified. End portion information of the specified signal change range is detected. Coordinates of the pointed position of the pointer are calculated using at least one of a plurality of pieces of detected end portion information.

Claims

1. A coordinate input apparatus for detecting a pointed position on a coordinate input region, comprising:

detection means for detecting the presence/absence of a pointing operation of pointing means on the coordinate input region;

specifying means for specifying a signal change range generated by the pointing operation of the pointing means on the coordinate input region with respect to an initial detection signal distribution of said detection means in an initial state in which no pointing operation is made on the coordinate input region;

end portion information detection means for detecting end portion information of the signal change range specified by said specifying means; and

calculation means for calculating coordinates of the pointed position of the pointing means using at least one of a plurality of pieces of end portion information detected by said end portion information detection means.

2. The apparatus according to claim 1, wherein said detection means comprises a plurality of detection means arranged at different positions of the coordinate input region, and

said calculation means calculates, as coordinates of the pointed position of the pointing means, an intersection of bisectors of an angle specified by intersections of line segments that connect coordinates specified by end portion information corresponding to each of the plurality of detection means and reference positions of the corresponding detection means.

3. The apparatus according to claim 1, wherein said calculation means determines a combination of end portion information to be used in coordinate calculations of the plurality of pieces of end portion information detected by said end portion information detection means on the basis of the number of signal change ranges specified by said specifying means.

4. The apparatus according to claim 1, further comprising:

determination means for, when said calculation means calculates a plurality of coordinates as coordinate candidates, determining coordinates corresponding to the pointed position of the pointing means from the coordinate candidates.

5. The apparatus according to claim 1, wherein said detection means comprises a plurality of detection means equivalent to arranged at different positions of the coordinate input region, and

said calculation means checks a degree of overlapping of signal change ranges corresponding to pointing operations made by a plurality of pointing means on the basis of the numbers of signal change ranges specified by said specifying means, which are obtained for respective plurality of detection means.

6. The apparatus according to claim 1, wherein said detection means detects the presence/absence of the pointing operation on the coordinate input region on the basis of the presence/absence of a shielded range when a shielding material that shields or reflects light is present between said detection means and a light source.

7. The apparatus according to claim 1, wherein said detection means detects the presence/absence of the pointing operation on the coordinate input region on the basis of the presence/absence of a shielded range when a shielding material that shields propagation of vibration is present between said detection means and an vibration generation source.

8. The apparatus according to claim 1, wherein the coordinate input region is used as a display surface of a display apparatus or is overlaid on the display surface of the display apparatus.

9. A display apparatus having a coordinate input apparatus of claim 1, wherein said coordinate input apparatus is overlaid on a display surface of said display apparatus.

10. A method of controlling a coordinate input apparatus which comprises a detection unit for detecting the presence/absence of a pointing operation of pointing means on a coordinate input region, and detects a pointed position on the coordinate input region, comprising:

a specifying step of specifying a signal change range generated by the pointing operation of the pointing means on the coordinate input region with respect to an initial detection signal distribution of the detection unit in an initial state in which no pointing operation is made on the coordinate input region;

an end portion information detection step of detecting end portion information of the signal change range specified in the specifying step; and

a calculation step of calculating coordinates of the pointed position of the pointing means using at least one of a plurality of pieces of end portion information detected in the end portion information detection step.

11. A program for implementing control of a coordinate input apparatus which comprises a detection unit for detecting the presence/absence of a pointing operation of pointing means on a coordinate input region, and detects a pointed position on the coordinate input region, comprising:

a program code of a specifying step of specifying a signal change range generated by the pointing operation of the pointing means on the coordinate input region with respect to an initial detection signal distribution of the detection unit in an initial state in which no pointing operation is made on the coordinate input region;

a program code of an end portion information detection step of detecting end portion information of the signal change range specified in the specifying step; and

a program code of a calculation step of calculating coordinates of the pointed position of the pointing means using at least one of a plurality of pieces of end portion information detected in the end portion information detection step.