Laser range finder with dynamically positioned detector aperture

Abstract

In one embodiment a LIDAR uses data indicating the directions of outgoing laser beams to dynamically position an aperture relative to a laser detector and thereby track reflections from laser beams with the aperture. A spatial light modulator (SLM) can create an electronically controlled aperture relative to the field of view of a laser receiver. The SLM can electronically control the transparency of a plurality of segments to block light from unintended sources such as the sun or other vehicles, using knowledge of expected directions of laser reflections. Within embodiments a LIDAR can use a set of laser steering parameters to transmit a laser beam in various directions. The LIDAR can also use some of the steering parameters (e.g. indicating reflection directions) to configure an electronically steerable aperture to dynamically limit the portion of a laser detector that can receive light based on the anticipated directions of corresponding laser reflections.

1 . A laser range finder comprising:
 control circuitry to obtain a set of laser steering parameters;   a laser transmitter, operably coupled to the control circuitry, to generate a laser beam in one or more directions, the one or more directions being based at least in part on the set of laser steering parameters;   a laser detector to receive reflected light from the laser beam; and   a spatial light modulator positioned in front of the laser detector, comprising a set of segments; and
 wherein at least one of the set of segments has a transparency that is electronically controlled based on at least one laser steering parameter from the set of laser steering parameters. 
   
     
     
         2 . The laser range finder of  claim 1  wherein the control circuitry further functions to generate an electronically steerable aperture in the spatial light modulator by electronically controlling the transparency of the at least one of the set of segments. 
     
     
         3 . The laser range finder of  claim 2  wherein the electronically steerable aperture has a size based at least in part on the at least one laser steering parameter from the set of laser steering parameters. 
     
     
         4 . The laser range finder of  claim 1  wherein the spatial light modulator is configured by the at least one laser steering parameter from the set of laser steering parameters to generate an aperture operable to transmit the reflected light from the laser beam to the laser detector in the one or more directions of the laser beam and block light from a plurality of directions exclusive from the one or more directions from reaching the laser detector. 
     
     
         5 . The laser range finder of  claim 1  wherein the control circuitry comprises an aperture positioner that functions to electronically control the at least one of the set of segments, based on the at least one of the set of laser steering parameters, to form an aperture operable to transmit the reflected light from the laser beam to the laser detector. 
     
     
         6 . The laser range finder of  claim 1  wherein the one or more directions are controlled at least in part by the set of laser steering parameters; and
 wherein the transparency of the at least one of the set of segments is electronically controlled by the at least one laser steering parameter from the set of laser steering parameters. 
 
     
     
         7 . The laser range finder of  claim 1   wherein a first subset of the set of segments are electronically controlled to block light;   wherein a second subset of the set of segments, having electronically controllable transparency, are to transmit light to the laser detector;   wherein the first and second subsets of the set of segments form an aperture with an electronically controllable position within the spatial light modulator; and   wherein the position of the aperture within the spatial light modulator is based at least in part on the at least one laser steering parameter form the set of laser steering parameters.   
     
     
         8 . The laser range finder of  claim 1  wherein the one more directions are a sequence of directions; and
 wherein the spatial light modulator is configured by the set of laser steering parameters to generate an aperture that tracks the reflected light from the laser beam to thereby transmit the reflected light from the laser beam to the laser detector. 
 
     
     
         9 . The laser range finder of  claim 1  wherein the laser detector has a field of view;
 wherein the control circuitry uses the at least one laser steering parameter from the set of laser steering parameters to calculate a location of the reflected light from the laser beam in the field of view; 
 wherein the transparency of the at least one of the set of segments is electronically controlled by the control circuitry to block light from a first portion of the field of view and thereby provide a second portion of the field of view through which light is transmitted to the laser detector; and 
 wherein the second portion contains the location. 
 
     
     
         10 . The laser range finder of  claim 1  wherein the laser transmitter is part of a steerable laser assembly; and
 wherein the steerable laser assembly is configured to dynamically steer the laser beam in the one or more directions using the set of laser steering parameters. 
 
     
     
         11 . The laser range finder of  claim 1  wherein the set of segments is a two dimensional plurality of segments; and wherein each segment in the two dimensional plurality of segments has electronically controllable transparency. 
     
     
         12 . The laser range finder of  claim 1  wherein the set of segments is a plurality of segments; and wherein each of the plurality of segments has a transparency that is electronically controllable. 
     
     
         13 . The laser range finder of  claim 1  wherein the spatial light modulator is controlled by the control circuitry using the at least one laser steering parameter from the set of laser steering parameters, to transmit reflected light in one or more reflection directions from the laser beam to the laser detector while blocking light from a plurality of directions exclusive from the one or more reflection directions from reaching the laser detector. 
     
     
         14 . The laser range finder of  claim 1  wherein the one more directions are a sequence of directions; and wherein the spatial light modulator is configured by the set of laser steering parameters to generate an electronically controllable aperture within the set of segments having a sequence of positions in the spatial light modulator that tracks the sequence of directions of the laser beam. 
     
     
         15 . The laser range finder of  claim 1  wherein the control circuitry is coupled to the spatial light modulator; and
 wherein the control circuitry functions at least in part to generate an electronically controlled aperture in the spatial light modulator, with a location within the spatial light modulator determined at least in part by the at least one laser steering parameter from the set of laser steering parameters. 
 
     
     
         16 . A laser range finder comprising:
 control circuitry configured to obtain a set of laser steering parameters;   a laser transmitter coupled to the control circuitry and configured to generate a laser beam in one or more directions; wherein the one or more directions are based at least in part on the set of laser steering parameters;   a laser detector to receive reflected light from the laser beam; and   a spatial light modulator positioned in front of the laser detector, comprising a set of segments, each with a corresponding transparency that is electronically controllable based on at least one laser steering parameter from the set of laser steering parameters.   
     
     
         17 . The laser range finder of  claim 16  wherein the laser detector comprises a field of view; and wherein the control circuitry is configured to electronically control, based on the at least one laser steering parameter from the set of laser steering parameters, a non-zero subset of the set of segments to block light from a first portion of the field of view to thereby transmit light through a second portion of the field of view such that the second portion is positioned relative to the first portion to transmit reflected light from the laser beam to the laser detector. 
     
     
         18 . The laser range finder of  claim 16 , wherein the control circuitry is further configured to electronically control for each of a subset of the set of segments the corresponding transparency, such that the subset of the set of segments forms an electronically controllable aperture with a position in the spatial light modulator that is based at least in part on the at least one laser steering parameter form the set of laser steering parameters. 
     
     
         19 . The laser range finder of  claim 16 , wherein the control circuitry is further configured to electronically control for each of a subset of the set of segments the corresponding transparency, such that the subset of the set of segments forms an electronically controlled aperture that transmits the reflected light from the laser beam through the spatial light modulator to the laser detector while blocking light from a plurality of directions from reaching the laser detector. 
     
     
         20 . The laser range finder of  claim 16 , wherein the control circuitry is configured to electronically control for each of a subset of the set of segments the corresponding transparency such that the subset forms an opening in the spatial light modulator and wherein the position of the opening is determined based at least in part on the at least one laser steering parameter form the set of laser steering parameters. 
     
     
         21 . A method comprising:
 obtaining a set of laser steering parameters;   generating with a laser transmitter and using the set of laser steering parameter, a laser beam in one or more directions;   at a spatial light modulator positioned in front of a laser detector and comprising a set of segments, electronically controlling a transparency of at least one of the set of segments using at least one of the set of laser steering parameters; and   receiving reflected light from the laser beam through the spatial light modulator at the laser detector.   
     
     
         22 . The method of  claim 21  further comprising the step of generating an electronically steerable aperture within the spatial light modulator; and
 wherein the electronically steerable aperture defines a portion of a field of view of the laser detector that is operable to receive light through the spatial light modulator. 
 
     
     
         23 . The method of  claim 22  further comprising the step of positioning the electronically steerable aperture using the at least one of the set of laser steering parameters, to transmit the reflected light from the laser beam through the spatial light modulator. 
     
     
         24 . The method of  claim 21  further comprising the steps of:
 generating an electronically controlled aperture with a location in the selective light modulator by electronically controlling the transparency of the at least one of the set of segments; and 
 modifying, using the at least one of the set of laser steering parameters, the location of the electronically controlled aperture relative to the laser detector, to track the reflected light from the laser beam. 
 
     
     
         25 . The method of  claim 21  further comprising the step of selecting the at least one of the set of segments based at least in part on receiving light from a light source other than the laser transmitter. 
     
     
         26 . The method of  claim 21  further comprising the step of selecting the at least one of the set of segments from the set of segments, using the at least one of the set of laser steering parameters. 
     
     
         27 . The method of  claim 21  wherein the step of electronically controlling the transparency of the at least one of the set of segments further comprising the step of selecting the transparency of the at least one of the set of segments, using the at least one of the set of laser steering parameters. 
     
     
         28 . The method of  claim 21  further comprising the step of generating, by electronically controlling the transparency of the at least one of the set of segments, an aperture in the spatial light modulator that transmits reflections from the laser beam through the spatial light modulator to the laser detector. 
     
     
         29 . The method of  claim 21  wherein the reflected light from the laser beam is received at the laser detector in one or more reflection directions and further comprises the step of,
 generating by electronically controlling the transparency of the at least one of the set of segments an aperture in the spatial light modulator that transmits the reflected light from the laser beam through the spatial light modulator to the laser detector in the one or more reflection directions while simultaneously blocking light from a plurality of directions surrounding the one or more reflection directions from reaching the laser detector.