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US 9,176,627 B2Granted
Camera-based touch system
AssigneeSMART Technologies ULC
InventorsGerald Morrison, David Holmgren
Life of this patent
Estimating the term…
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.
Claims34
An imaging assembly comprising:
- a substantially rectangular frame to surround a region of interest in front of a display surface;
- and
- at least two digital cameras, each digital camera having a selectable pixel array and being mounted adjacent a different corner of said frame, each digital camera having a field of view that (i) images at least a portion of said display surface, (ii) images a least a portion of said frame, and (iii) extends at least beyond an adjacent peripheral edge of said frame, said digital cameras being oriented to capture overlapping images of said region of interest, each digital camera further comprising a processor configured to process a subset of pixel data of images captured by the digital camera to detect the existence of a pointer therein, wherein during processing of each captured image, said processor forms a difference image representing differences between pixel data in the captured image and corresponding pixel data in a background image, generates a histogram comprising a plurality of elements by selectively summing pixel intensities of said difference image, compares the elements of the histogram to a noise threshold, determines the existence of a pointer when a plurality of elements of the histogram exceed the noise threshold and determines the center of the pointer by determining the location of the element of the plurality having the highest value.
An imaging assembly comprising:
- a substantially rectangular frame to surround a region of interest in front of a display surface;
- at least two imaging devices, each imaging device having a selectable pixel array and being mounted adjacent a different corner of said frame, said imaging devices being oriented so that the field of view of each imaging device (i) encompasses at least a portion of said display surface, (ii) encompasses a least a portion of said frame, and (iii) extends at least beyond an adjacent peripheral edge of said frame, said imaging devices configured to capture overlapping images of said region of interest;
- and
- a processor associated with each imaging device, each processor configured to process a subset of pixel data of images captured by the associated imaging device to detect the existence of a pointer therein, wherein during processing of each captured image, said processor forms a difference image representing differences between pixel data in the captured image and corresponding pixel data in a background image, generates a histogram comprising a plurality of elements by selectively summing pixel intensities of said difference image, compares the elements of the histogram to a noise threshold, determines the existence of a pointer when a plurality of elements of the histogram exceed the noise threshold and determines the center of the pointer by determining the location of the element of the plurality having the highest value.
1 more element
A touch system comprising:
- a substantially rectangular touch surface;
- a region of interest that is in front of, and at least partially includes, said touch surface;
- at least two digital cameras, each digital camera having a selectable pixel array and being mounted adjacent a different corner of said touch surface, each digital camera having a field of view that (i) images at least a portion of said touch surface, (ii) images a least a portion of said frame, and (iii) extends at least beyond an adjacent peripheral edge of said touch surface, said digital cameras being oriented to capture overlapping images of said region of interest, each digital camera further comprising a processor configured to process a subset of pixel data of images captured by the digital camera to detect the existence of a pointer therein, wherein during processing of each captured image, said processor forms a difference image representing differences between pixel data in the captured image and corresponding pixel data in a background image, generates a histogram comprising a plurality of elements by selectively summing pixel intensities of said difference image, compares the elements of the histogram to a noise threshold, determines the existence of a pointer when a plurality of elements of the histogram exceed the noise threshold and determines the center of the pointer by determining the location of the element of the plurality having the highest value.
A touch system comprising:
- a substantially rectangular touch surface;
- a region of interest that is in front of, and at least partially includes, said touch surface;
- at least two imaging devices, each imaging device having a selectable pixel array and being mounted adjacent a different corner of said touch surface, said imaging devices being oriented so that the field of view of each imaging device (i) encompasses at least a portion of said touch surface, (ii) encompasses a least a portion of said frame, and (iii) extends at least beyond an adjacent peripheral edge of said touch surface, said imaging devices configured to capture overlapping images of said region of interest;
- and
- a processor associated with each digital camera, each processor configured to process a subset of pixel data of images captured by the associated imaging device to detect the existence of a pointer therein, wherein during processing of each captured image, said processor forms a difference image representing differences between pixel data in the captured image and corresponding pixel data in a background image, generates a histogram comprising a plurality of elements by selectively summing pixel intensities of said difference image, compares the elements of the histogram to a noise threshold, determines the existence of a pointer when a plurality of elements of the histogram exceed the noise threshold and determines the center of the pointer by determining the location of the element of the plurality having the highest value.
2 more elements
Dependencies are inferred from the claim text.