Method and apparatus for determining contact areas within a touch sensing region
First Claim
1. A computer implemented method of determining one or more contact areas within a touch sensing region comprising the steps of:
- positioning a light source such that light emanating from said light source passes across said touch sensing region;
positioning a plurality of light detectors such that at least a portion of said light source is within the field of view of each of said plurality of light detectors;
providing a processor configured to identify one or more positive fans, each of said positive fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is occluded;
said processor configured to identify one or more negative fans, each of said negative fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is not occluded;
said processor configured to additively combine said positive fans with one another to determine positive regions; and
said processor configured to subtractively combine said negative fans with said positive regions to determine said contact areas.
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Abstract
The invention determines the location of multiple, simultaneous contact areas on a touch sensing region using a light source and several light detectors. The invention is robust against occlusion and many of the ambiguities that can arise with multiple, simultaneous contact areas. Generally, the light source is positioned such that light emanating the light source passes across the touch sensing region, and the light detector are positioned such that at least a portion of the light source is within the field of view of each light detector. The contact areas are determined by identifying positive fans corresponding to an angular sector of the field of view of a light detector in which the view of the light source is occluded and negative fans corresponding to an angular sector of the field of view of a light detector in which the view of the light source is not occluded. The positive fans and negative fans are then additively and subtractively combined, respectively, to determine the contact areas.
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Citations
21 Claims
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1. A computer implemented method of determining one or more contact areas within a touch sensing region comprising the steps of:
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positioning a light source such that light emanating from said light source passes across said touch sensing region; positioning a plurality of light detectors such that at least a portion of said light source is within the field of view of each of said plurality of light detectors; providing a processor configured to identify one or more positive fans, each of said positive fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is occluded; said processor configured to identify one or more negative fans, each of said negative fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is not occluded; said processor configured to additively combine said positive fans with one another to determine positive regions; and said processor configured to subtractively combine said negative fans with said positive regions to determine said contact areas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for determining one or more contact areas within a touch sensing region, comprising:
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a light source positioned such that light emanating from said light source passes across said touch sensing region; a plurality of light detectors positioned such that at least a portion of said light source is within the field of view of each of said plurality of light detectors; a processor configured to identify one or more positive fans, each of said positive fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is occluded; said processor configured to identify one or more negative fans, each of said negative fans corresponding to an angular sector of the field of view of one of said light detectors in which the view of the light source is not occluded; said processor configured to additively combine said positive fans with one another to determine positive regions; and said processor configured to subtractively combine said negative fans with said positive regions to determine said contact areas.
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Specification