Multiple-beam optical position sensor for automotive occupant detection
First Claim
1. A multiple-beam optical position sensor system for measuring the approximate three-dimensional profile and position of an object, said system comprising:
- a light emitting diode array projector comprising a plurality of light emitting diodes for generating a set of time-multiplexed optical beams that illuminate the object, wherein only one light emitting diode is turned on at any one time, and wherein such beams have different deflection angles which results in arbitrary two-dimensional arrangements of illumination spots on the object;
a two-dimensional transverse-effect photodiode having a first pair of photocurrent outputs for outputting x and y current values that are indicative of x and y locations of reflected spots formed on the photodiode produced by the plurality of beams;
imaging optics for imaging the set of time-multiplexed optical beams onto the two-dimensional transverse-effect photodiode to produce the reflected spots on the photodiode; and
processing means coupled between the two-dimensional transverse-effect photodiode and the plurality of light emitting diodes of the light emitting diode array projector for turning on each light emitting diode sequentially in time to generate the set of time-multiplexed optical beams, and for processing signals derived from a pair of photocurrent outputs from the two-dimensional transverse-effect photodiode to determine the x and y location of each imaged spot on the two-dimensional transverse-effect photodiode, and the range to the object along each beam direction, and wherein the x and y locations and range provide an approximate measure of the three-dimensional profile and position of the object.
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Accused Products
Abstract
An optical sensor system for measuring the approximate three-dimensional profile and position of an object. A reduced to practice embodiment of the optical sensor system has been used to measure the three-dimensional profile and position of an object within a range of 40 inches to 2 inches with high accuracy and high update rates (>1 KHz). The sensor system generates a set of optical beams using a projection lens and multiple light emitting diodes (LED) located in a back focal plane of the projection lens. The position of each LED determines the angle of a beam transmitted thereby. By turning on each LED sequentially in time, a set of beams is generated at various angles that illuminates the object to produce a set of spots on the object. The range from each LED to each of the spatially-separated illuminated spots on the object is determined by imaging the spots onto a two-dimensional transverse-effect photodiode. Signals derived from a pair of photocurrent outputs from the photodiode are processed to determine the positions of the spots on the two-dimensional transverse-effect photodiode. Computations are performed that implement optical triangulation to determine the range and approximate three-dimensional profile to the object.
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Citations
7 Claims
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1. A multiple-beam optical position sensor system for measuring the approximate three-dimensional profile and position of an object, said system comprising:
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a light emitting diode array projector comprising a plurality of light emitting diodes for generating a set of time-multiplexed optical beams that illuminate the object, wherein only one light emitting diode is turned on at any one time, and wherein such beams have different deflection angles which results in arbitrary two-dimensional arrangements of illumination spots on the object; a two-dimensional transverse-effect photodiode having a first pair of photocurrent outputs for outputting x and y current values that are indicative of x and y locations of reflected spots formed on the photodiode produced by the plurality of beams; imaging optics for imaging the set of time-multiplexed optical beams onto the two-dimensional transverse-effect photodiode to produce the reflected spots on the photodiode; and processing means coupled between the two-dimensional transverse-effect photodiode and the plurality of light emitting diodes of the light emitting diode array projector for turning on each light emitting diode sequentially in time to generate the set of time-multiplexed optical beams, and for processing signals derived from a pair of photocurrent outputs from the two-dimensional transverse-effect photodiode to determine the x and y location of each imaged spot on the two-dimensional transverse-effect photodiode, and the range to the object along each beam direction, and wherein the x and y locations and range provide an approximate measure of the three-dimensional profile and position of the object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification