RANGE CAMERA
First Claim
Patent Images
1. A range camera operable to determine distances to and reflectance for features of a scene that the range camera images, the range camera comprising:
- a light source operable to transmit light to illuminate a scene that the range camera images;
a photosensor having light sensitive pixels;
optics having an optical axis and optical center configured to receive light reflected from the transmitted light by features in the scene and image the reflected light on a plurality of the pixels, each of which plurality of pixels registers reflected light from a feature of the scene that the optics images on the pixel to provide a registered scene irradiance (RSI) for the feature;
a calibration image comprising a registered calibration irradiance (RCI) for each of the light sensitive pixels that provides a measure of irradiance that the pixel registers responsive to light reflected from light transmitted by the light source by a region of a calibration surface having known shape, reflectance, and location that the range camera images on the pixel; and
a controller operable to determine a reflectance for a feature of the scene imaged on a first pixel of the photosensor comprised in the plurality of pixels responsive to the RSI for the feature and an RCI for a region of the calibration surface imaged on a second pixel of the photosensor corresponding to the feature imaged on the first pixel.
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Accused Products
Abstract
An active illumination range camera that acquires a range and a picture image of a scene and provides a reflectance for a feature in the scene responsive to a distance for the feature provided by the range image, a registered irradiance for the feature provided by the picture image and registered irradiance for a region of a calibration surface corresponding to the feature provided by an image of the calibration surface acquired by the range camera.
27 Citations
23 Claims
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1. A range camera operable to determine distances to and reflectance for features of a scene that the range camera images, the range camera comprising:
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a light source operable to transmit light to illuminate a scene that the range camera images; a photosensor having light sensitive pixels; optics having an optical axis and optical center configured to receive light reflected from the transmitted light by features in the scene and image the reflected light on a plurality of the pixels, each of which plurality of pixels registers reflected light from a feature of the scene that the optics images on the pixel to provide a registered scene irradiance (RSI) for the feature; a calibration image comprising a registered calibration irradiance (RCI) for each of the light sensitive pixels that provides a measure of irradiance that the pixel registers responsive to light reflected from light transmitted by the light source by a region of a calibration surface having known shape, reflectance, and location that the range camera images on the pixel; and a controller operable to determine a reflectance for a feature of the scene imaged on a first pixel of the photosensor comprised in the plurality of pixels responsive to the RSI for the feature and an RCI for a region of the calibration surface imaged on a second pixel of the photosensor corresponding to the feature imaged on the first pixel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of determining reflectance for a feature of a scene, the method comprising:
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using an active lighting range camera to acquire a range image and a picture image of the scene responsive to light transmitted by the range camera to illuminate the scene that is reflected by features in the scene back to the range camera; determining a location of the feature in the FOV responsive to the range image; determining registered irradiance of the range camera by light reflected from the transmitted light by the feature responsive to the picture image; determining a corresponding region of a calibration surface imaged in a calibration image acquired by the range camera; determining registered irradiance of the range camera by light reflected from the transmitted light by the corresponding region responsive to the calibration image; and using the determined registered irradiances from the feature and the corresponding calibration region and known reflectance of the calibration surface to determine the reflectance of the feature. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A range camera operable to determine distances to and reflectance for features of a scene that the range camera images, the range camera comprising:
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a light source operable to transmit light to illuminate a scene that the range camera images; a photosensor having a plurality of light sensitive pixels; a look up table (LUT) having for each pixel of the plurality of pixels a set of values for a first feature having known reflectance that is imaged on the pixel from a known first distance from the camera and illuminated by light at known intensity from the light source, the set of values comprising a registered calibration irradiance (RCI) for light reflected by the first feature from the illuminating light; and a controller that determines a reflectance of a second feature imaged on the pixel from a second distance responsive to square of the ratio of the first distance divided by the second distance, the RCI, and a registered scene irradiance (RSI) that the pixel provides for light from the light source that is reflected by the second feature and imaged on the pixel. - View Dependent Claims (22, 23)
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Specification