Coordinate input apparatus, control method thereof, and program

• US 20060232568A1
• Filed: 04/11/2006
• Published: 10/19/2006
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Sato, Hajime
• Granted Patent: US 7,589,715 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 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A signal change range generated by a pointing operation of a pointer on a coordinate input region is specified in correspondence with the initial detection signal distribution of a detection unit in an initial state without pointing on the coordinate input region. Pieces of end information of the specified signal change range are detected. The validity of a detection state in the end information detection step is determined by using the plurality of pieces of detected end information. On the basis of the determination result, the coordinates of the point position of the pointer are calculated from the plurality of pieces of end information.

Claims

1. A coordinate input apparatus for detecting a plurality of point positions on a coordinate input region, comprising:

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

specifying means for specifying a signal change range generated by a pointing operation of the pointing means on the coordinate input region in correspondence with an initial detection signal distribution of said detection means in an initial state without pointing on the coordinate input region;

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

determination means for determining validity of a detection state in said end information detection means by using a plurality of pieces of end information detected by said end information detection means; and

calculation means for calculating coordinates of a point position of the pointing means from the plurality of pieces of end information on the basis of a determination result of said determination means.

2. The apparatus according to claim 1, wherein

said determination means comprises comparison means for comparing the plurality of coordinates calculated using the plurality of pieces of end information, and

the validity of the detection state is determined on the basis of a comparison result by said comparison means.

3. The apparatus according to claim 1, wherein

said determination means comprises comparison means for comparing intersection coordinates of tangents each of which connects a position of an end indicated by one of the plurality of pieces of end information on the coordinate input region to said detection means corresponding to the end information, and

the validity of the detection state is determined on the basis of a comparison result by said comparison means.

4. A coordinate input apparatus for detecting a plurality of point positions on a coordinate input region, comprising:

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

specifying means for specifying a signal change range generated by a pointing operation of the pointing means on the coordinate input region in correspondence with an initial detection signal distribution of said detection means in an initial state without pointing on the coordinate input region;

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

calculation means for calculating coordinates of a point position of the pointing means by using a plurality of pieces of end information detected by said end information detection means;

end information calculation means for calculating new end information on the basis of the coordinates calculated by said calculation means and shape information of the pointing means; and

determination means for determining validity of the coordinates calculated by said calculation means, on the basis of the new end information calculated by said end information calculation means.

5. The apparatus according to claim 4, further comprising control means for controlling, on the basis of a determination result of said determination means, output of the coordinates calculated by said calculation means.

6. The apparatus according to claim 4, wherein

said determination means comprises:

first calculation means for calculating first angle information with respect to said detection means based on a position, on the coordinate input region, of an end indicated by the end information detected by said end information detection means;

second calculation means for calculating second angle information with respect to said detection means based on the position, on the coordinate input region, of the end indicated by the end information detected by said end information detection means; and

comparison means for comparing the first angle information with the second angle information, and

the validity of the coordinates calculated by said calculation means is determined on the basis of a comparison result by said comparison means.

7. A control method of a coordinate input apparatus which includes a detection unit to detect presence/absence of pointing means on a coordinate input region and detects a point position on the coordinate input region, comprising:

a specifying step of specifying a signal change range generated by a pointing operation of the pointing means on the coordinate input region in correspondence with an initial detection signal distribution of the detection unit in an initial state without pointing on the coordinate input region;

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

a determination step of determining validity of a detection state in the end information detection step by using a plurality of pieces of end information detected in the end information detection step; and

a calculation step of calculating coordinates of a point position of the pointing means from the plurality of pieces of end information on the basis of a determination result in the determination step.

8. A control method of a coordinate input apparatus which includes a plurality of detection units to detect presence/absence of pointing means on a coordinate input region and detects a point position on the coordinate input region, comprising:

a specifying step of specifying a signal change range generated by a pointing operation of a pointing means on the coordinate input region in correspondence with an initial detection signal distribution of the detection unit in an initial state without pointing on the coordinate input region;

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

a calculation step of calculating coordinates of a point position of the pointing means by using a plurality of pieces of end information detected in the end information detection step;

an end information calculation step of calculating new end information on the basis of the coordinates calculated in the calculation step and shape information of the pointing means; and

a determination step of determining validity of the coordinates calculated in the calculation step on the basis of the new end information calculated in the end information calculation step.

9. A program which implements control of a coordinate input apparatus which includes a detection unit to detect presence/absence of pointing means on a coordinate input region and detects a point position on the coordinate input region, comprising:

a program code for a specifying step of specifying a signal change range generated by a pointing operation of the pointing means on the coordinate input region in correspondence with an initial detection signal distribution of the detection unit in an initial state without pointing on the coordinate input region;

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

a program code for a determination step of determining validity of a detection state in the end information detection step by using a plurality of pieces of end information detected in the end information detection step; and

a program code for a calculation step of calculating coordinates of a point position of the pointing means from the plurality of pieces of end information on the basis of a determination result in the determination step.

10. A program which implements control of a coordinate input apparatus which includes a plurality of detection units to detect presence/absence of pointing means on a coordinate input region and detects a point position on the coordinate input region, comprising:

a program code for a specifying step of specifying a signal change range generated by a pointing operation of a pointing means on the coordinate input region in correspondence with an initial detection signal distribution of the detection unit in an initial state without pointing on the coordinate input region;

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

a program code for a calculation step of calculating coordinates of a point position of the pointing means by using a plurality of pieces of end information detected in the end information detection step;

a program code for an end information calculation step of calculating new end information on the basis of the coordinates calculated in the calculation step and shape information of the pointing means; and

a program code for a determination step of determining validity of the coordinates calculated in the calculation step on the basis of the new end information calculated in the end information calculation step.