Camera-based touch system
First Claim
Patent Images
1. A camera-based touch system comprising:
- at least two image sensors associated with a touch surface and having overlapping fields of view encompassing said touch surface, said at least two image sensors acquiring images of said touch surface from different vantages; and
processing structure processing pixel subsets of the images acquired by said at least two image sensors, pixel data of each pixel subset being processed to determine the existence of a pointer by calculating a median location of the pointer, said processing structure using the calculated median locations to triangulate the location of the pointer relative to said touch surface.
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Abstract
A camera-based touch system (50) includes a passive touch surface (60) and at least two cameras (63) associated with the touch surface. The at least two cameras (63) have overlapping fields of view (FOV) encompassing the touch surface. The at least two cameras (63) acquire images of the touch surface from different locations and generate image data. A processor (54) receives and processes image data generated by the at least two cameras to determine the location of the pointer relative to the touch surface when the pointer is captured in images acquired by the at least two cameras. Actual pointer contact with the touch surface and pointer hover above the touch surface can be determined.
346 Citations
56 Claims
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1. A camera-based touch system comprising:
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at least two image sensors associated with a touch surface and having overlapping fields of view encompassing said touch surface, said at least two image sensors acquiring images of said touch surface from different vantages; and processing structure processing pixel subsets of the images acquired by said at least two image sensors, pixel data of each pixel subset being processed to determine the existence of a pointer by calculating a median location of the pointer, said processing structure using the calculated median locations to triangulate the location of the pointer relative to said touch surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A camera-based touch system comprising:
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a generally rectangular passive touch surface on which contacts are made using a pointer; at least two digital image sensors, each image sensor being mounted adjacent a different corner of said touch surface, said digital image sensors having overlapping fields of view encompassing said touch surface, said digital image sensors acquiring images looking generally across said touch surface; and processing structure receiving image data output by said digital image sensors, said processing structure processing the image data to determine the existence of a pointer in acquired images by calculating median locations x of the pointer and using the calculated median locations to triangulate the location of said pointer relative to said touch surface and to determine whether said pointer is in contact with said touch surface. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of detecting the position of a pointer relative to a touch surface comprising the steps of:
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acquiring multiple overlapping images of a pointer proximate to said touch surface using image sensors having fields of view at least looking at said touch surface; processing at processing structure pixel subsets of said acquired images to determine the existence of a pointer by calculating median locations of the pointer; and using the calculated median locations to triangulate the location of said pointer relative to said touch surface. - View Dependent Claims (33, 34)
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35. A method of detecting the position of a pointer relative to a touch surface comprising the steps of:
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acquiring multiple overlapping images of a pointer proximate to said touch surface using cameras having fields of view at least looking at said touch surface and outputting from each camera a pixel subset of each image, each said pixel subset comprising pixel data from selected pixel rows of the acquired image; and receiving at processing structure the outputted pixel subsets of said acquired images and processing the pixel data of said pixel subsets to determine the location of said pointer relative to said touch surface using triangulation, wherein during said processing the existence of said pointer is determined by calculating median lines of the pointer and wherein the location of said pointer is determined by calculating the intersection point of the median lines and using triangulation to determine the coordinates of said intersection point. - View Dependent Claims (36, 37)
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38. A camera-based touch system comprising:
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at least two digital cameras associated with a touch surface and having overlapping fields of view encompassing said touch surface, said at least two digital cameras acquiring images of said touch surface from different vantages and for each acquired image, outputting a pixel subset of the acquired image, said pixel subset comprising pixel data from selected pixel rows of the acquired image; and processing structure receiving said pixel subsets of the acquired images generated by said at least two digital cameras, the pixel data of the pixel subsets being processed to generate pointer data when a pointer exists in said acquired images, said processing structure triangulating the pointer data to determine the location of a pointer relative to said touch surface, wherein each of said digital cameras includes an image sensor and a digital signal processor, said digital signal processor receiving image output from said image sensor and executing a find pointer routine to determine if a pointer is in each image acquired by said digital camera, and if so the median line x of said pointer and wherein the digital signal processor of each digital camera further executes an update background image routine to update the background image after each image is acquired. - View Dependent Claims (39, 40, 41, 42)
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43. A camera-based touch system comprising:
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at least two image sensors associated with a touch surface and having overlapping fields of view encompassing said touch surface, said at least two image sensors acquiring images of said touch surface from different vantages; and processing structure processing pixel subsets of the acquired images generated by said at least two image sensors, pixel data of the pixel subsets being processed to determine the existence of a pointer in said acquired images, when a pointer exists in said acquired images said processing structure determining the location of the pointer relative to said touch surface using triangulation, wherein during determination of the existence of the pointer, said processing structure builds a vertical intensity histogram including columns of pixel intensities representing differences between an acquired image and a background image, the column of said vertical intensity histogram having the largest pixel intensity above a threshold level being used to define the center of said pixel subset, the width of said pixel subset being defined by columns of said vertical intensity histogram on opposite sides of the column defining the center of said pixel subset that have pixel intensities greater than said threshold level. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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Specification