PROVIDING DYNAMIC FIELD OF VIEW FOR LIGHT RECEIVED FROM A DYNAMIC POSITION

• US 20190369216A1
• Filed: 01/24/2018
• Published: 12/05/2019
• Est. Priority Date: 01/24/2017
• Status: Active Application

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Anderson, Michael Howard, Davis, Scott Robert, Luey, Benjamin
• Application Number:
  US16/480,220
• Publication Number:
  US 20190369216A1
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/00 Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection
• CPC Class Codes: G01S 7/4876 by removing unwanted signals G01S7/495 takes precedence
• CPC Class Codes: G01S 7/4912 Receivers

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.

Claims

1. A method for dynamically adjusting a composite field of view in an optical detection system having a photosensitive detector, the method comprising:

selecting a first group of detector pixels for detecting a portion of a light beam transmitted towards a target region;

adjusting an angle of the light beam transmitted towards the target region; and

selecting a second group of detector pixels for detecting a portion of the light beam having the adjusted angle, the selecting the first group of detector pixels and the selecting the second group of detector pixels including using recorded positions of detected portions of the light beam.

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 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 scanning the light beam over the target region in a pattern and recording the positions of the detected light beam using a full count N of detector pixels.

6. The method according to claim 1, comprising summing pixels in the first group of detector pixels prior to digitization and summing pixels in the second group of detector pixels prior to digitization.

7. The method according to claim 1, comprising summing pixels in the first group of detector pixels after digitization and summing pixels in the second group of detector pixels after digitizations.

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

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

10. The method according to claim 9, comprising scanning the 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 one of the determined angles.

21. The method of claim 6, wherein summing pixels in the first group of detector pixels prior to digitization comprises summing respective currents from the first group of detector pixels;

and

wherein summing pixels in the second group of detector pixels prior to comprises summing respective currents from the second group of detector pixels.

5. (canceled)

11. A system for dynamically adjusting a composite field of view in an optical detection system, the system comprising:

a transmitter configured to transmit a 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 select a first group of detector pixels to receive a portion of the light beam corresponding to the first angle and a second group of detector pixels to receive a portion of the light beam corresponding to the second angle from the target region, the selecting the first group of detector pixels and the selecting the second group of detector pixels including using recorded positions of received portions of the light beam.

12. The system of claim 11, wherein the control circuitry is configured to subtract at least one detector pixel from the first group of detector pixels and add at least one detector pixel to the first group of detector pixels to form the second group of detector pixels.

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

14. The system according to claim 11, wherein the transmitter is configured to scan the light beam over the target region in a pattern and the system includes a memory to record the positions of the detected light beam using a full count N of detector pixels.

16. The system according to claim 11, comprising summing circuitry to sum pixels in the first group of detector pixels prior to digitization and configured to sum pixels in the second group of detector pixels prior to digitization.

17. The system according to claim 11, comprising summing circuitry to sum pixels in the first group of detector pixels after digitization and sum pixels in the second group of detector pixels after digitization.

22. The system according to claim 11, wherein the summing circuitry is configured to sum respective currents from the first group of detector pixels prior to digitization and configured to sum respective currents from the second group of detector pixels prior to digitization.

15. (canceled)

18. A method for dynamically adjusting a composite field of view in an optical detection system, the method comprising:

transmitting a light beam towards a target region;

receiving a responsive light beam from the target region onto a first group of pixels corresponding to a first composite field of view;

adjusting an angle of the transmitted light beam and;

based on the adjusted angle of the transmitted 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 corresponding to a second composite field of view, including using recorded positions of detected portions of the light beam; and

transmitting the 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 corresponding to the second field of view.

19. The method of claim 18, further comprising:

sequentially scanning a light beam across a target region; and

determining at least one angle of the light beam at which a received portion of the transmitted light beam is aligned with a boundary of at least two pixels.

20. The method according to claim 18, wherein the at least one angle of light beam is determined when a center of the received portion of the transmitted light beam is aligned with a boundary of at least two pixels.