System and method for measuring reference and returned light beams in an optical system

Patent metadata

Field	Value
Publication number	US-10890649-B2
Application number	US-201615235041-A
Country	US
Kind code	B2
Filing date	Aug 11, 2016
Priority date	Aug 11, 2016
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

Disclosed herein are techniques for measuring a reference beam and a corresponding returned beam from a target in a measurement system using a single sensor array. The system is configured such that the location of the reference beam is space apart from the location of the returned beam on the sensor array. A first set of sensor elements on the sensor array corresponding to the reference beam is dynamically activated based on a laser beam scanning control signal. The detection signal from the first set of sensor elements is used to determine a location and/or a pattern of the reference beam, which are then used to estimate a location and/or a pattern of the corresponding returned beam on the same sensor array and dynamically select and activate a second set of sensor elements on the sensor array based on the estimated location and/or pattern of the corresponding returned beam.

First claim

What is claimed is:

1. A system comprising:
a light source configured to transmit a light beam that scans in one or two dimensions;
a two-dimensional (2-D) sensor array comprising a plurality of sensor elements;
a beam splitting device configured to direct a first portion of the light beam as a reference beam onto a first area on the 2-D sensor array, wherein the first area changes as the light beam scans;
a transmitter optical subsystem configured to direct a second portion of the light beam towards a target object;
a receiver optical subsystem configured to direct a returned portion of the second portion of the light beam reflected by the target object onto a second area on the 2-D sensor array, the second area spaced apart from the first area and changing as the light beam scans; and
a sensor controller communicatively coupled to the 2-D sensor array for controlling the 2-D sensor array by:
measuring an actual location of the reference beam on the first area of the 2-D sensor array; and
selectively activating sensor elements in the second area of the 2-D sensor array, based on the measured actual location of the reference beam in the first area on the 2-D sensor array,
wherein the selectively activated sensor elements in the second area measure the returned portion of the second portion of the light beam reflected by the target object.

2. The system of claim 1 , wherein the sensor controller is configured to:
selectively activate a first set of sensor elements of the 2-D sensor array in a first estimated area comprising the first area, based on a laser beam scanning control signal that controls a scanning direction of the transmitted light beam;
receive a detection signal from the first set of sensor elements;
deactivate the first set of sensor elements after receiving the detection signal; and
determine the actual location of the first portion of the light beam on the 2-D sensor array based on the detection signal.

3. The system of claim 2 , further comprising a timing measurement circuit configured to extract timing information from the detection signal.

4. The system of claim 3 , wherein the timing measurement circuit comprises an analog-to-digital converter or a time-to-digital converter.

5. The system of claim 2 , wherein the sensor controller is further configured to:
determine an estimated location of the returned portion of the second portion of the light beam on the 2-D sensor array, based on the measured actual location of the first portion of the light beam; and
activate a second set of sensor elements of the 2-D sensor array based on the estimated location of the returned portion of the second portion of the light beam.

6. The system of claim 5 , wherein the estimated location of the returned portion of the second portion of the light beam on the 2-D sensor array comprises a dimension and a pattern of the returned portion of the second portion of the light beam on the 2-D sensor array.

7. The system of claim 5 , wherein the sensor controller is configured to determine the estimated location of the returned portion of the second portion of the light beam on the 2-D sensor array based on a relationship between the estimated location of the returned portion of the second portion of the light beam on the 2-D sensor array and the actual location of the first portion of the light beam on the 2-D sensor array.

8. The system of claim 5 , wherein the sensor controller is further configured to:
Receive a detection signal from the second set of sensor elements; and
deactivate the second set of sensor elements after receiving the detection signal from the second set of sensor elements.

9. The system of claim 8 , further comprising a measurement circuit configured to extract timing information and light intensity information from the detection signal from the second set of sensor elements.

10. The system of claim 9 , further comprising an analyzer configured to determine a characteristic of the target object based on the timing information and the light intensity information.

11. The system of claim 1 , wherein the sensor controller is configured to:
dynamically select a location, dimension, and pattern of an area of the 2-D sensor array; and
dynamically activate a set of sensor elements in the selected area of the 2-D sensor array and deactivate other sensor elements of the 2-D sensor array.

12. The system of claim 11 , wherein the selected area comprises one of a circular area, a rectangular area, and an oval area of the 2-D sensor array.

13. The system of claim 1 , wherein the 2-D sensor array comprises a silicon photomultiplier (SiPM) sensor comprising a plurality of single-photon avalanche diode (SPAD) micro-cells.

14. The system of claim 1 , wherein the transmitter optical subsystem comprises the beam splitting device.

15. The system of claim 1 , wherein the first area and the second area are on opposite sides of the 2-D sensor array.

16. A method for measuring a reference beam and a corresponding returned beam from a target, the method comprising:
selectively activating, based on a laser beam scanning control signal, a first set of sensor elements of a two-dimensional (2-D) sensor array, the first set of sensor elements corresponding to a location of the reference beam on the 2-D sensor array, the reference beam comprising a portion of a light beam controlled by the laser beam scanning control signal;
receiving a detection signal from the first set of sensor elements;
measuring an actual location of the reference beam on the 2-D sensor array based on the detection signal from the first set of sensor elements;
determining an estimated location of the returned beam on the 2-D sensor array based on the measured actual location of the reference beam, the returned beam returned by the target illuminated by the light beam; and
selectively activating a second set of sensor elements on the 2-D sensor array, based on the estimated location of the returned beam, wherein the selectively activated second set of sensor elements measure the returned beam returned by the target.

17. The method of claim 16 , wherein:
the reference beam is directed to the 2-D sensor array by a beam splitting device;
the returned beam is directed to the 2-D sensor array by a receiver optical subsystem; and
the actual location of the reference beam on the 2-D sensor array is spaced apart from the estimated location of the returned beam on the 2-D sensor array.

18. The method of claim 16 , further comprising:
deactivating the first set of sensor elements after receiving the detection signal from the first set of sensor elements; and
extracting timing information from the detection signal from the first set of sensor elements.

19. The method of claim 16 , further comprising:
receiving a detection signal from the second set of sensor elements;
deactivating the second set of sensor elements after receiving the detection signal from the second set of sensor elements; and
extracting timing information from the detection signal from the second set of sensor elements.

20. The method of claim 19 , wherein extracting timing information from the detection signal from the second set of sensor elements comprises extracting timing information from the detection signal from the second set of sensor elements using an analog-to-digital converter or a time-to-digital converter.

21. The method of claim 19 , further comprising determining a characteristic of the target based on the timing informat

Assignees

• Qualcomm Inc

Inventors

• Jarosinski Tadeusz
• Slobodyanyuk Volodimir
• Wyrwas John
• Raina Manav
• Mclaren Elbert

Classifications

• G01S17/42 Primary

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• G01S7/4863 Primary

  Detector arrays, e.g. charge-transfer gates · CPC title

• G01S7/4817

  relating to scanning · CPC title

• G01S17/06

  Systems determining position data of a target · CPC title

• G01S7/4814 Primary

  of transmitters alone · CPC title