Electronically steered flash LIDAR

• US 8,736,818 B2
• Filed: 08/16/2010
• Issued: 05/27/2014
• Est. Priority Date: 08/16/2010
• Status: Active Grant

• Current Assignee: BAE Systems Space & Mission Systems Incorporated
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Ramond, Tanya M., Adkins, Carl M., Applegate, Jeff T., Delker, Thomas P., Ruppert, Lyle S., Weimer, Carl S.
• Primary Examiner(s): Alsomiri, Isam
• Assistant Examiner(s): RODRIGUEZ, VICENTE M
• Application Number:
  US12/857,354
• Publication Number:
  US 20120038903A1
• Time in Patent Office: 1,380 Days
• Field of Search: 356/4.07
• US Class Current: 356/4.07
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4868 Controlling received signal intensity or exposure of sensor

Abstract

Methods and systems for adaptively controlling the illumination of a scene are provided. In particular, a scene is illuminated, and light reflected from the scene is detected. Information regarding levels of light intensity received by different pixels of a multiple pixel detector, corresponding to different areas within a scene, and/or information regarding a range to an area within a scene, is received. That information is then used as a feedback signal to control levels of illumination within the scene. More particularly, different areas of the scene can be provided with different levels of illumination in response to the feedback signal.

Claims

1. A method for illuminating a scene, comprising:

outputting light in a first illumination pattern, wherein the first illumination pattern includes a first plurality of beams that illuminate the scene at a first point in time;

determining at least one of an intensity of light reflected from the scene as a result of illumination of the scene by the first illumination pattern or a range to an area of the scene determined from light included in the first illumination pattern;

in response to determining the at least one of an intensity of light reflected from the scene as a result of illumination of the scene by the first illumination pattern or a range to an area of the scene determined from light included in the first illumination pattern, outputting light in a second illumination pattern, wherein the second illumination pattern includes a second plurality of beams that illuminate the scene at a second point in time, and wherein the first illumination pattern differs from the second illumination pattern.

2. The method of claim 1, wherein outputting light in a second illumination pattern includes steering at least one of the beams included in the first plurality of beams.

3. The method of claim 2, wherein outputting the second plurality of beams includes controlling at least a first beam included in the first plurality of beams, and wherein controlling at least a first beam included in the first plurality of beams includes at least one of:

controlling an intensity of the first beam,

controlling the first beam such that the first beam is incident on a selected area within the scene, and

controlling the first beam such that the first beam is incident on an area adjacent the scene.

4. The method of claim 1, wherein the second illumination pattern is output in response to determining an intensity of light received at a first element of a multiple element detector as a result of illumination of the scene by the first illumination pattern.

5. The method of claim 4, wherein determining an intensity of light reflected from the scene while the scene is illuminated by the first illumination pattern includes receiving a signal from at least the first element of the multiple element detector.

6. The method of claim 5, wherein the signal received from the first element of the multiple element detector is greater than a threshold amount,

wherein a signal received from a second element of the multiple element detector is less than the threshold amount,

wherein outputting light in a second illumination pattern includes reducing an intensity of a first beam illuminating an area of the scene from which light received by the first element of the multiple element detector is reflected as compared to the intensity of a corresponding beam in the first illumination pattern, and

wherein outputting light in a second illumination pattern does not include reducing an intensity of a second beam illuminating an area of the scene from which light received by the second element of the multiple element detector is reflected as compared to the intensity of a corresponding beam in the first illumination pattern.

7. The method of claim 5, further comprising:

directing the second illumination pattern to the scene;

in response to detecting that an intensity of light reflected from the scene while the scene is illuminated by the second illumination pattern exceeds a threshold amount, controlling the second illumination pattern to produce a third illumination pattern, wherein the second illumination pattern differs from the third illumination pattern.

8. The method of claim 5, wherein the intensity of light detected by the first element of the multiple element detector while the scene is illuminated by the second illumination pattern is less than the intensity of light detected by the first element of the multiple element detector while the scene is illuminated by the first illumination pattern.

9. The method of claim 2, wherein outputting light in a second illumination pattern includes steering a first one of the beams independently of a second one of the beams in the first plurality of beams.

10. The method of claim 1, wherein outputting light in a second illumination pattern includes electronically altering the first illumination pattern to create the second illumination pattern.

11. A lidar system, including:

a light source, wherein the light source generates at least a first light pulse comprising a first beam of light;

a first acoustic optic modulator, wherein the beam of light generated by the light source is provided to the first acoustic optic modulator;

a first radio frequency driver, wherein a selected number of radio frequencies are output to the first acoustic optic modulator by the first radio frequency driver, and wherein a first illumination pattern including a number of steerable beams corresponding to the selected number of radio frequencies are output from the first acoustic optic modulator in response to the selected number of radio frequencies at a first point in time;

a focal plane array;

a controller, wherein the controller is in communication with at least the light source, the first radio frequency driver, and the focal plane array, wherein a time at which the first light pulse is generated by the light source and a time at which a return signal comprising at least some light from the first light pulse is received at the focal plane array provides range information, wherein information regarding an intensity of the return signal is provided to the controller, wherein the information regarding an intensity of the return signal is used to determine at least one parameter of a control signal provided by the controller to the first radio frequency driver, wherein the at least one parameter of the control signal provided by the controller to the first radio frequency driver is applied in outputting a second illumination pattern at a second point in time, and wherein the first and second illumination patterns are different from one another.

12. The system of claim 11, wherein the at least one parameter of a control signal includes an intensity of a first steerable beam output from the first acoustic optic modulator and an intensity of a second steerable beam output from the first acoustic optic modulator, wherein the intensity of the first steerable beam relative to the second steerable beam is changed between the first light pulse generated by the light source and a second pulse generated by the light source.

13. The system of claim 11, wherein the at least one parameter of a control signal includes a steering angle of first, second and third steerable beams output from the first acoustic optic modulator, wherein the first steerable beam is steered independently of the second and third steerable beams.