US 11,747,453 B1
Calibration system for light detection and ranging (lidar) devices
Ralph H. Shepard, Menlo Park, CA (US); Pierre-Yves Droz, Los Altos, CA (US); Caner Onal, Palo Alto, CA (US); and Hui Son, Hayward, CA (US)
Assigned to Waymo LLC, Mountain View, CA (US)
Filed by Waymo LLC, Mountain View, CA (US)
Filed on Mar. 18, 2020, as Appl. No. 16/822,481.
Claims priority of provisional application 62/930,009, filed on Nov. 4, 2019.
Int. Cl. G01S 17/88 (2006.01); G01S 17/00 (2020.01); G01S 17/02 (2020.01); G01S 17/08 (2006.01); G01S 7/497 (2006.01); G01S 7/4913 (2020.01); G01S 17/06 (2006.01)
CPC G01S 7/497 (2013.01) [G01S 7/4913 (2013.01); G01S 17/08 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A lidar calibration system, comprising:
a calibration target comprising a surface having at least one characterized reflectivity, wherein the surface is configured to receive one or more calibration signals emitted by a lidar device along one or more optical axes when the lidar device is separated from the calibration target by an adjustable distance;
at least one lens positioned along the one or more optical axes to modify the one or more calibration signals;
an adjustable attenuator positioned along the one or more optical axes, wherein the adjustable attenuator is configured to attenuate each of the one or more calibration signals to simulate, in combination with the at least one lens, a distance that is greater than the adjustable distance; and
a calibration controller configured to analyze data associated with detected reflections of the one or more calibration signals based on the at least one characterized reflectivity, the adjustable distance, and characteristics of the at least one lens.