On-car stray-light testing cart

Patent metadata

Field	Value
Publication number	US-11330253-B2
Application number	US-202016994115-A
Country	US
Kind code	B2
Filing date	Aug 14, 2020
Priority date	Apr 17, 2019
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

Methods, systems, and apparatus for a stray-light testing apparatus. In one aspect, the apparatus includes an optical assembly including a spatially extended light source and one or more optical elements arranged to direct light from the spatially extended light source along an optical path, a moveable frame supporting the optical assembly including one or more adjustable alignment features for guiding positioning of the stray-light testing apparatus relative to an onboard camera on a vehicle, and a shrouding mechanism attached to the frame and positioned on the frame such that, when the stray-light testing apparatus is aligned relative to the onboard camera on the vehicle and the optical path of the optical assembly is within the field of view of the onboard camera, ambient light exposure for the onboard camera is below a threshold.

First claim

What is claimed is:

1. A stray-light testing apparatus comprising:
an optical assembly comprising a spatially extended light source and one or more optical elements arranged to direct light from the spatially extended light source along an optical path;
a frame supporting the optical assembly; and
a shroud attached to the frame and arranged to cover an area of the optical path,
wherein, when the stray-light testing apparatus is aligned relative to an onboard camera on an automobile and an optical path of the optical assembly is within a field of view of the onboard camera, the optical assembly directs light from the spatially extended light source to the onboard camera and the shroud blocks ambient light exposure from the onboard camera.

2. The apparatus of claim 1 , wherein the frame is affixed to one or more of a floor, ceiling, and wall of a testing area including the stray-light testing apparatus.

3. The apparatus of claim 2 , wherein the frame is configured to allow the automobile to be positioned underneath a portion of the stray-light testing apparatus.

4. The apparatus of claim 1 , wherein the shroud is positioned on the frame such that ambient light exposure for the onboard camera is below 25% of a dynamic range of a sensor of the onboard camera.

5. The apparatus of claim 4 , wherein the shroud further comprises one or more fixture points to attach the shroud over the onboard camera on the automobile.

6. The apparatus of claim 1 , wherein the optical assembly further comprises two rotational stages to adjust an angle of incidence of the spatially extended light source with respect to the onboard camera.

7. The apparatus of claim 1 , wherein the spatially extended light source is partially enclosed by a lens tube.

8. The apparatus of claim 1 , further comprising a controller in data communication with i) the spatially extended light source and operable to provide instructions to the spatially extended light source, and ii) an onboard data collection unit for the automobile.

9. The apparatus of claim 1 , wherein the spatially extended light source is a spatially extended light source at infinity with respect to a field of view of the onboard camera.

10. The apparatus of claim 1 , wherein blocking the ambient light exposure from the onboard camera by the shroud comprises reducing ambient light exposure for the onboard camera below a threshold.

11. A method for determining stray-light performance of an onboard camera of an automobile, the method comprising:
positioning a shroud with respect to the onboard camera such that the shroud blocks ambient light exposure from the onboard camera;
selecting a first light intensity from a plurality of different light intensities from a light source;
exposing the onboard camera to the first light intensity from the light source; and
capturing image data by the onboard camera while exposing the onboard camera to the first light intensity from the light source; and

determining, based on the captured images, performance metrics for the onboard camera.

12. The method of claim 11 , wherein blocking the ambient light exposure from the onboard camera by the shroud comprises reducing the ambient light exposure for the onboard camera below a threshold.

13. The method of claim 11 , wherein positioning the shroud with respect to the onboard camera comprises aligning, using one or more adjustable alignment features, the shroud with respect to the onboard camera.

14. The method of claim 13 , wherein position the shroud with respect to the onboard camera comprises positioning a vehicle including the onboard camera with respect to the shroud.

15. The method of claim 11 , wherein determining performance metrics comprises determining a rejection ratio of the onboard camera.

16. The method of claim 15 , wherein determining the rejection ratio comprises:
capturing, for each light intensity of the plurality of different light intensities and by the onboard camera, a two-dimensional image; and
determining, as a function of a radius extending from a center point of the light source, an extent of the light source with an intensity above a threshold relative intensity over the two-dimensional images captured by the onboard camera.

17. The method of claim 11 , wherein determining performance metrics comprises determining a glare spread function for the onboard camera.

18. The method of claim 11 , further comprising:
determining, from the performance metrics, a source of stray-light conditions for the onboard camera; and
in response, generating stray-light condition compensation for the onboard camera.

19. The method of claim 18 , wherein stray-light condition compensation comprises compensation for a glare and/or saturation by a light source in a field of view of the onboard camera.

Assignees

• Waymo Llc

Inventors

• Lu Chen David
• Chubb Erik

Classifications

• G01J1/08

  Arrangements of light sources specially adapted for photometry {standard sources, also using luminescent or radioactive material} · CPC title

• G01J1/0271

  Housings; Attachments or accessories for photometers · CPC title

• G01J2001/083

  Testing response of detector · CPC title

• G01J1/4204

  with determination of ambient light (solar light G01J2001/4266) · CPC title

• G01J1/0488

  with spectral filtering · CPC title