| US 7,538,894 B2 | ||
| Coordinate input apparatus, control method thereof, and program | ||
| Kiwamu Kobayashi, Yokohama (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Apr. 11, 2006, as Appl. No. 11/401,389. | ||
| Claims priority of application No. 2005-118971 (JP), filed on Apr. 15, 2005; application No. 2005-118979 (JP), filed on Apr. 15, 2005; and application No. 2005-264426 (JP), filed on Sep. 12, 2005. | ||
| Prior Publication US 2006/0232792 A1, Oct. 19, 2006 | ||
| Int. Cl. G01B 11/14 (2006.01) | ||
| U.S. Cl. 356—614 [356/622; 345/175] | 32 Claims |
| 1. A coordinate input apparatus for detecting a point position on a coordinate input region, comprising:
a plurality of sensor means each of which includes a light projecting unit to project light to the coordinate input region
and a light receiving unit to receive arrival light, wherein each of the plurality of sensor means is provided around the
coordinate input region;
reflection means, provided at a periphery of the coordinate input region, for retroreflecting incident light; and
determination means for determining a point state of pointing means in the coordinate input region on the basis of a number
and intensities of shadows which are present in light intensity distributions obtained from said plurality of sensor means
in accordance with pointing by the pointing means.
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