Touch-Sensitive Display Devices

A method of ambient light interference suppression in a touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• the method comprising:
• amplitude modulating said touch sensor light source;
• and
• processing a plurality of said captured touch sense images captured when said touch sensor light source is off to compensate for ambient light in a said captured touch sense image captured when said touch sensor light source is on.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said device further comprises:
• a filter in front of said camera configured such that a first set of pixels of said camera receive light at a first peak wavelength and a second set of pixels of said camera receive light of a second, different peak wavelength, wherein said first set of pixels receive more light from said touch sensor light source than said second set of pixels.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said device further comprises:
• a system to modulate said touch sensor light source responsive to a modulation signal;
• and
• wherein each of a plurality of pixels of said camera has an associated signal processing circuit, coupled to receive said modulation signal, and configured to suppress a component of a light level signal from a respective pixel not modulated by said modulation signal.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said device further comprises:
• a system to modulate said touch sensor light source responsive to a modulation signal to generate a temporal modulation pattern of said touch sensor light source;
• and
• wherein said signal processor is configured to process captured touch sense images defining said temporal modulation light pattern to suppress ambient light in a said captured touch sense image, wherein said captured touch sense images defining said temporal modulation comprise more than just a single laser on a single laser off image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said device further comprises:
• a system to encode a spatial pattern in one or both of said projected plane of light and a said captured image;
• and
• wherein said signal processor is further configured to selectively detect said spatial pattern in a said captured touch sense image to suppress ambient illumination.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said signal processor is further configured to:
• determine a level of ambient illumination from captured touch sense images captured by said camera when said touch sensor light source is on;
• compensate for said determined level of ambient illumination in a captured touch sense image to provide an ambient-compensated touch sense image;
• and
• process said ambient-compensated touch service image to determine position data for said object from said image of light scattered by said object.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said signal processor is further configured to:
• spatially filter a said touch sense image prior to said object location identification to reject light scattered from a region predicted to be shadowed by an object, or portion of an object, nearer said touch sensor light source than said region.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image, wherein said touch sensor light projection is amplitude modulated;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, configured to:
• compensate for ambient light captured by said camera by determining a difference image, wherein said difference image is dependent on a difference between a said touch sense image captured when said touch sensor light projection is on and a said touch sense image captured when said touch sensor light projection is off;
• process said difference image, or an image derived from said difference image, to perform one or both of image erosion and image blurring, to generate a processed difference image comprising an eroded or blurred version of said difference image;
• and
• operate on said processed difference image to identify a location of said object relative to said displayed image.

A method of attenuating touch image artefacts in touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image, wherein said touch sensor light projection is amplitude modulated;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, the method comprising:
• compensating for ambient light captured by said camera by determining a difference image, wherein said difference image is dependent on a difference between a said touch sense image captured when said touch sensor light projection is on and a said touch sense image captured when said touch sensor light projection is off;
• eroding and/or blurring said difference image, or an image derived from said difference image, to generate a processed difference image;
• and
• operating on said processed difference image to identify a location of said object relative to said displayed image;
• wherein said difference image comprises signed image data;
• and
• wherein said eroding/blurring comprises eroding/blurring until substantially all negative image data has been removed from said difference image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor laser light source to project a plane of light above said displayed image;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said signal processor is further configured to high-pass filter data from a said touch sense image to attenuate spatial frequencies below a threshold spatial frequency prior to said processing to identify said location of said object.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image at two discrete wavelengths;
• a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• and
• wherein said device further comprises:
• one or more optical wavelength notch filter in front of said camera;
• and
• a system to vary application of said one or more notch filters to said camera spatially and/or temporally to match each of said discrete wavelengths;
• and
• wherein said signal processor is further configured to process said spatial and/or temporal variation to suppress an ambient light level in a said captured image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project two planes of light above said displayed image, at different respective first and second positions;
• a camera directed to capture a touch sense image from a region including at least a portion of each said plane of light, said touch sense image comprising light scattered from said planes of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a plurality of said touch sense images from said camera to identify a location of said object relative to said displayed image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a first camera directed to capture a first touch sense image from a region including at least a portion of said plane of light, said first touch sense image comprising light scattered from said plane of light by an object approaching said displayed image;
• wherein said first camera has a viewing axis directed down towards said plane of light at an acute angle to a line in said plane of light;
• a second camera having a viewing axis directed substantially into a plane of said plane of light to capture a line image of said plane of light;
• and
• a signal processor coupled to said cameras, to process a said touch sense image from said cameras to identify a location of said object relative to said displayed image, wherein said signal processor is configured to filter or correlate said first touch sense image using said line image to reject a spurious signal in said first touch sense image absent from said line image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera having a viewing axis directed into said plane of light to capture a touch sense line image a comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said camera comprises an imaging system including an aperture;
• and
• wherein said signal processor is further configured to:
• process said line image to determine a distance of said object from said camera from a defocusing effect of said aperture on a captured image of said scattered light and a direction of said object from a location of said scattered light in said line image.

A touch sensitive image display device, the device comprising:

• an image projector to project a displayed image onto a surface in front of the device;
• a touch sensor light source to project a plane of light above said displayed image;
• a camera having a viewing axis directed into said plane of light to capture a touch sense line image a comprising light scattered from said plane of light by an object approaching said displayed image;
• and
• a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a location of said object relative to said displayed image;
• wherein said camera comprises either a) a plenoptic camera, or b) a pair of cameras;
• and
• wherein said signal processor is further configured to process said line image to determine both a distance of said object from said camera and a direction of said object from a location of said scattered light in said line image.