Providing dynamic field of view for light received from a dynamic position

Patent metadata

Field	Value
Publication number	US-12019189-B2
Application number	US-201816480220-A
Country	US
Kind code	B2
Filing date	Jan 24, 2018
Priority date	Jan 24, 2017
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A system and method for providing a dynamic composite field of view in a scanning lidar system, such as to improve a signal-to-noise ration of detected light. The dynamic composite field of view can include a subset of the available detector pixels, and can thereby reduce noise introduce by noise sources that can scale with a detector area, such as dark current and gain peaking that can be caused by a capacitance of the photodetector.

First claim

The invention claimed is:

1. A method for dynamically adjusting a composite field of view in an optical detection system having a photosensitive detector, the method comprising:
scanning a first light beam over a target region in a pattern and recording positions of the detected first light beam using a count N of detector pixels;
selecting a first group of detector pixels comprising a first composite field of view for detecting a portion of a second light beam transmitted towards the target region;
summing the first group of detector pixels including summing at least two pixels in the first group of detector pixels in the analog domain prior to a digitization;
adjusting an angle of the second light beam transmitted towards the target region; and
selecting a second group of detector pixels comprising a second composite field of view for detecting a portion of the second light beam having the adjusted angle;
summing the second group of detector pixels including summing at least two pixels in the second group of detector pixels in the analog domain prior to another digitization, the selecting the first group of detector pixels and the selecting the second group of detector pixels including using the recorded positions of the detected first light beam, a count of the first group of detector pixels and a count of the second group of detector pixels being less than the count N.

2. The method of claim 1 , comprising subtracting at least one detector pixel from the first group of detector pixels and adding at least one detector pixel to the first group of detector pixels to form the second group of detector pixels.

3. The method according to claim 1 , wherein the detected second light beam has an area corresponding to M pixels and the first group of detector pixels and the second group of detector pixels include M+1 pixels, and the photosensitive detector includes N pixels, where N is greater than M+1.

4. The method according to claim 1 , comprising summing every pixel in the first group of detector pixels in the analog domain prior to the digitization and summing every pixel in the second group of detector pixels in the analog domain prior to the other digitization.

5. The method according to claim 1 , comprising summing at least two pixels or summed pixel groups in the first group of detector pixels after the digitization and summing at least two pixels or summed pixel groups in the second group of detector pixels after the other digitization.

6. The method according to claim 1 , comprising using the first group of detector pixels to detect a position of the second light beam and selecting the second group of detector pixels when a center of the detected position of the second light beam is at a boundary between two pixels.

7. The method according to claim 1 , comprising scanning the first light beam over the target region and determining respective angle for each time the light beam crosses a boundary between two detector pixels using a full count N of detector pixels.

8. The method according to claim 7 , comprising scanning the second light beam over the target region and selecting a new group of M+1 detector pixels each time the angle of the light beam corresponds to a respective one of the determined respective angles.

9. A system for dynamically adjusting a composite field of view in an optical detection system, the system comprising:
a transmitter configured to transmit a second light beam towards a target region at a first angle and then at a second angle;
a photodetector including a plurality of pixels; and
control circuitry configured to:
record positions of a detected first light beam scanned over the target region in a pattern using a count N of the plurality of photodetector pixels;
select a first group of the plurality of photodetector pixels comprising a first composite field of view to receive a portion of the second light beam corresponding to the first angle and a second group of the plurality of photodetector pixels comprising a second composite field of view to receive a portion of the second light beam corresponding to the second angle from the target region, the selecting the first group and the selecting the second group including using recorded positions of the detected first light beam, a count of the first group of the plurality of photodetector pixels and a count of the second group of the plurality of photodetector pixels being less than the count N; and
summing circuitry, configured to sum the first group of detector pixels including to sum at least two pixels in the first group of photodetector pixels in the analog domain prior to a digitization and sum the second group of detector pixels including to sum at least two pixels in the second group of photodetector pixels in the analog domain prior to another digitization.

10. The system of claim 9 , wherein the control circuitry is configured to subtract at least one photodetector pixel from the first group of photodetector pixels and add at least one photodetector pixel to the first group of photodetector pixels to form the second group of photodetector pixels.

11. The system according to claim 9 , wherein the received portion of the second light beam has an area corresponding to M photodetector pixels and the first group of photodetector pixels and the second group of photodetector pixels include M+1 detector pixels, and the photodetector includes N detector pixels, where N is greater than M+1.

12. The system according to claim 9 , wherein the summing circuitry is configured to sum every pixel in the first group of photodetector pixels prior to the digitization and sum every pixel in the second group of photodetector pixels prior to the other digitization.

13. The system according to claim 9 , wherein the summing circuitry is configured to sum at least two pixels or summed pixel groups in the first group of photodetector pixels after the digitization and sum at least two pixels or summed pixel groups in the second group of photodetector pixels after the other digitization.

14. A method for dynamically adjusting a composite field of view in an optical detection system, the method comprising:
scanning a first light beam over a target region in a pattern and recording positions of the detected first light beam using a count N of detector pixels;
transmitting a second light beam towards the target region;
in response to the second light beam, receiving a responsive light beam from the target region onto a first group of pixels comprising a first composite field of view;
summing the first group of detector pixels including summing at least two pixels in the first group of pixels in the analog domain prior to a digitization;
adjusting an angle of the transmitted second light beam and, based on the adjusted angle of the transmitted second light beam, removing at least one pixel from the first group of pixels and adding at least one pixel to the first group of pixels to form a second group of pixels comprising a second composite field of view, including using recorded positions of the first light beam;
transmitting the second light beam towards the target region at the adjusted angle and receiving a responsive light beam from the target region onto the second group of pixels comprising the second field of view, a count of the first group of detector pixels and a count of the second group of detector pixels being less than the count N; and
summing the second group of detector pixels including summing at least two pixels in the second group of pixels in the analog domain prior to another digitization.

15. The method of claim 14 , further compris

Assignees

• Analog Devices Inc

Inventors

• Anderson Michael Howard
• Davis Scott Robert
• Luey Benjamin

Classifications

• G01S17/06

  Systems determining position data of a target · CPC title

• G01S17/00

  Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems · CPC title

• G01S7/4876

  by removing unwanted signals (G01S7/495 takes precedence) · CPC title

• G01S7/487

  Extracting wanted echo signals {, e.g. pulse detection} · CPC title

• G01S7/4861

  Circuits for detection, sampling, integration or read-out · CPC title