Depth illumination and detection optics
First Claim
1. A depth detection system that illuminates a scene with infrared radiation in order to obtain depth images of the scene based on reflections of the infrared radiation that are within a narrow infrared band, comprising:
- a depth image detector, comprising;
an illumination source adapted to output collimated infrared illumination radiation sufficient to illuminate a scene including multiple objects;
a circular polarization structure including a quarter wave plate positioned to receive collimated linearly polarized infrared illumination radiation having a first linear polarization orientation and to output a circularly polarized collimated infrared beam;
a diffractive optics structure positioned adjacent to the circular polarization structure and adapted to receive the circularly polarized collimated infrared beam and adapted to output a pattern of circularly polarized infrared illumination radiation to the scene to illuminate the multiple objects; and
a detector adapted to receive a reflection of the pattern from the multiple objects, the detector including an array of collector elements covered by a filter tuned to the infrared illumination radiation output by the illumination source;
the circular polarization structure, the illumination source and the diffractive optics structure positioned relative to one another such that the circular polarization structure blocks from being incident on the illumination source, at least a portion of the infrared illumination radiation that, after being output by the illumination source, is scattered back from the diffractive optics structure towards the illumination source; and
the circular polarization structure, the illumination source and the diffractive optics structure positioned relative to one another such that at least a portion of the infrared illumination radiation that is scattered back from the diffractive optics structure towards the illumination source, by the diffractive optics structure, is converted from circularly polarized infrared illumination radiation to linearly polarized infrared illumination radiation having a second linear polarization orientation that is orthogonal to the first linear polarization orientation.
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Accused Products
Abstract
A depth image capture device uses a circular polarization structure positioned at the output of an illumination radiation source, such as a diode laser. A linear polarization element receives the collimated illumination radiation and provides polarized radiation to a quarter wave plate. Radiation exits the quarter wave plate as circularly polarized radiation and is provided to a diffractive optical element outputting a pattern to illuminate a target. A detector receives a reflection of the output pattern from the target.
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Citations
20 Claims
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1. A depth detection system that illuminates a scene with infrared radiation in order to obtain depth images of the scene based on reflections of the infrared radiation that are within a narrow infrared band, comprising:
a depth image detector, comprising; an illumination source adapted to output collimated infrared illumination radiation sufficient to illuminate a scene including multiple objects; a circular polarization structure including a quarter wave plate positioned to receive collimated linearly polarized infrared illumination radiation having a first linear polarization orientation and to output a circularly polarized collimated infrared beam; a diffractive optics structure positioned adjacent to the circular polarization structure and adapted to receive the circularly polarized collimated infrared beam and adapted to output a pattern of circularly polarized infrared illumination radiation to the scene to illuminate the multiple objects; and a detector adapted to receive a reflection of the pattern from the multiple objects, the detector including an array of collector elements covered by a filter tuned to the infrared illumination radiation output by the illumination source; the circular polarization structure, the illumination source and the diffractive optics structure positioned relative to one another such that the circular polarization structure blocks from being incident on the illumination source, at least a portion of the infrared illumination radiation that, after being output by the illumination source, is scattered back from the diffractive optics structure towards the illumination source; and the circular polarization structure, the illumination source and the diffractive optics structure positioned relative to one another such that at least a portion of the infrared illumination radiation that is scattered back from the diffractive optics structure towards the illumination source, by the diffractive optics structure, is converted from circularly polarized infrared illumination radiation to linearly polarized infrared illumination radiation having a second linear polarization orientation that is orthogonal to the first linear polarization orientation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A motion detection and tracking system, comprising:
a capture device in a housing including; a laser outputting infrared illumination radiation sufficient to illuminate a scene including multiple objects; a collimating lens positioned to receive the infrared illumination radiation and provide collimated infrared illumination radiation; a diffractive optical element positioned such that backscatter therefrom of the infrared illumination radiation back toward the laser would cause instability in the laser absent an intervening circular polarization structure that includes a linear polarization element and a quarter wave plate; the intervening circular polarization structure adapted to block, from reaching the laser, the infrared illumination radiation that is backscattered from the diffractive optical element, to thereby maintain stability of the laser; the linear polarization element of the circular polarization structure positioned between the collimating lens and the diffractive optical element and adapted to receive the collimated infrared illumination radiation and provide a linearly polarized output having a first linear polarization orientation; the quarter wave plate of the circular polarization structure positioned to receive the polarized output of the linear polarization element and adapted to provide circularly polarized output illumination radiation such that the diffractive optical element thereby outputs circularly polarized infrared illumination radiation in a pattern to illuminate the scene including the multiple objects; and a detector adapted to receive a reflection of the pattern from the multiple objects, the detector including a narrow band infrared filter which is matched to an output wavelength of the laser. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A motion detection and tracking system, comprising:
a motion capture device including; a laser diode having an infrared illumination radiation output sufficient to illuminate a scene including multiple objects; a collimating lens positioned at the output of the laser diode to provide a collimated infrared beam; a diffractive optical element positioned such that backscatter therefrom of infrared illumination radiation back toward the laser diode would cause instability in the laser diode absent intervening optical elements; the intervening optical elements comprising a linear polarization element positioned adjacent to the collimating lens and providing an output and a quarter wave plate positioned adjacent to the linear polarization element and receiving the output of the linear polarization element, the quarter wave plate outputting a circularly polarized beam; the diffractive optical element positioned adjacent to the quarter wave plate and configured to output a pattern of the circularly polarized beam to illuminate the scene including multiple objects; and a detector positioned to receive a reflection of the pattern from the multiple objects, the detector including a narrow band infrared filter which is matched to an output wavelength of the laser diode. - View Dependent Claims (16, 17, 18, 19, 20)
Specification