Calibration system and method for lidar systems
First Claim
1. A calibration system for a light-emitting apparatus which bases determinations relating to remote objects upon received backscattered light comprising:
- an optical line having a first end;
reflective means connected to said line for inducing light reflection at a fixed distance from said first end of said optical line; and
distributing means for diffusing light emitted from said light-emitting apparatus substantially isotropically within a reflective cavity defined by said distributing means, said first end of said optical line being disposed relative to said reflective cavity to receive diffused light and to direct light reflected by said reflective means toward said distributing means for return to said light-emitting apparatus.
1 Assignment
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Accused Products
Abstract
A calibration system and method include isotropically diffusing high-intensity light emitted from a detection apparatus, with the diffused light being coupled to at least one optical line, typically an optical fiber. In the preferred embodiment, the apparatus to be calibrated is a light detection and ranging (LIDAR) apparatus and the isotropic diffusion is achieved by means of an integrating sphere. For calibrating distance calculations, the optical fiber includes a reflecting mechanism, such as Bragg gratings, at a fixed and known distance from the input end of the optical fiber. The reflecting mechanisms simulates the presence of a remote object at the known distance. For a velocity calculation, a frequency offset may be introduced to the light propagating through the optical fiber, thereby simulating a Doppler shift induced by a moving object. The simulations of the presence and movement of remote objects are used to calibrate the apparatus.
42 Citations
19 Claims
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1. A calibration system for a light-emitting apparatus which bases determinations relating to remote objects upon received backscattered light comprising:
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an optical line having a first end; reflective means connected to said line for inducing light reflection at a fixed distance from said first end of said optical line; and distributing means for diffusing light emitted from said light-emitting apparatus substantially isotropically within a reflective cavity defined by said distributing means, said first end of said optical line being disposed relative to said reflective cavity to receive diffused light and to direct light reflected by said reflective means toward said distributing means for return to said light-emitting apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A calibration system for a light detection and ranging (LIDAR) apparatus comprising:
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an integrating sphere having an aperture aligned with said LIDAR apparatus to receive an incoming beam into a substantially spherical interior and to direct a return light signal to said LIDAR apparatus; a plurality of optical fibers having first ends located at said integrating sphere such that each optical fiber is in optical communication with said substantially spherical interior; and reflectors positioned along said optical fibers to reflect light propagating from said first ends for return to said substantially spherical interior, said reflected light forming said return light signal to said LIDAR apparatus. - View Dependent Claims (11, 12, 13, 14)
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15. A method of calibrating a light-emitting apparatus which bases determinations of ranges of remote objects upon received backscattered light comprising steps of:
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positioning an output beam of said apparatus relative to an aperture of an integrating sphere such that said output beam impinges a substantially spherical interior surface of said integrating sphere, which substantially isotropically diffuses said output beam, thereby significantly attenuating light intensity; simulating presence of a remote object at a known distance from said apparatus, including positioning a first end of an optical fiber relative to said surface to receive light from said surface and including reflecting said received light propagating through said optical fiber at a known position relative to said first end; directing a return light signal from said surface to said apparatus such that said return light signal is representative of said light reflected at said known position of said optical fiber; and adjusting a calculation of the distance of said simulated remote object from said apparatus to coincide with said known distance. - View Dependent Claims (16, 17, 18, 19)
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Specification