Synchronized image capturing for electronic scanning LIDAR systems comprising an emitter controller and plural sensor controllers

Patent metadata

Field	Value
Publication number	US-11953600-B2
Application number	US-202117473736-A
Country	US
Kind code	B2
Filing date	Sep 13, 2021
Priority date	May 13, 2019
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

Abstract

Embodiments describe an electronically scanning optical system including an emitter array configured to emit light into a field, a time of flight (TOF) sensor array configured to detect emitted light reflected back from the field, an image sensor array configured to detect ambient light in the field, where a field of view of the emitter array corresponds to a field of view of the TOF sensor array and at least a subset of a field of view of the image sensor array. The optical system further including an emitter controller configured to activate a subset of the plurality of light emitters at a time, a TOF sensor controller configured to synchronize the readout of individual TOF photosensors concurrently with the firing of corresponding light emitters, and an image sensor controller configured to capture an image that is representative of the field during the emission cycle.

First claim

What is claimed is:

1. An electronically scanning optical system comprising:
an emitter array comprising a plurality of light emitters configured to emit light at an operating wavelength into a field external to the optical system;
a first sensor array comprising a plurality of depth photosensors configured to detect emitted light reflected back from the field;
an optical filter disposed between the field and the first sensor array and operable to pass a narrow band of light that includes the operating wavelength to the first sensor array;
a second sensor array comprising a plurality of image photosensors configured to detect ambient light in the field, wherein a field of view of the emitter array corresponds to a field of view of the first sensor array and at least a subset of a field of view of the second sensor array;
an emitter controller coupled to the emitter array and configured to activate the plurality of light emitters in each emission cycle by activating a subset of the plurality of light emitters at a time;
a first sensor controller coupled to the first sensor array and configured to synchronize a readout of individual depth photosensors within the first sensor array concurrently with a firing of corresponding light emitters in the emitter array such that each light emitter in the emitter array can be activated and each depth photosensor in the first sensor array can be readout through the emission cycle; and
a second sensor controller coupled to the second sensor array and configured to readout at least a portion of the second sensor array having a field of view that overlaps with a field of view of the emitter array to capture an image that is representative of the field during the emission cycle.

2. The electronically scanning optical system of claim 1 wherein the operating wavelength is an infrared or near-infrared wavelength.

3. The electronically scanning optical system of claim 1 wherein in each instance in which the emitter controller activates a subset of the plurality of light emitters, the second sensor controller activates and reads out from a subset of image photosensors that share the field of view of the activated subset of light emitters.

4. The electronically scanning optical system of claim 1 wherein in each instance in which the emitter controller activates a subset of the plurality of light emitters, the second sensor controller activates the entire second sensor array but reads out from a subset of image photosensors that share the field of view of the activated subset of light emitters.

5. The electronically scanning optical system of claim 1 wherein each image photosensor in the second sensor array is configured to be activated individually, and the second sensor controller is configured to synchronize activation of groups of image photosensors concurrently with firing of corresponding banks of light emitters in a sequential order.

6. The electronically scanning optical system of claim 5 wherein a duration of a first activation of a first group of image photosensors is different from a duration of a second activation of a second group of image photosensors.

7. The electronically scanning optical system of claim 1 wherein the entire second sensor array is configured to be activated at a time, and the second controller is configured to synchronize the activation of the entire second sensor array and the readout of respective groups of image photosensors concurrently with the firing of corresponding banks of light emitters in a sequential order.

8. The electronically scanning optical system of claim 7 wherein an activation rate of the second sensor array of image photosensors is higher than an activation rate of the emitter array.

9. The electronically scanning optical system of claim 8 wherein the second sensor controller is configured to readout image data from more than one activation of the first sensor array and associate the readout image data with an activation of a corresponding bank of light emitters.

10. The electronically scanning optical system of claim 1 wherein field of view of the second sensor array is larger than the field of view of the emitter array.

11. The electronically scanning optical system of claim 1 wherein an overall dimension of the second sensor array of image photosensors is larger than an overall dimension of the emitter array of light emitters.

12. The electronically scanning optical system of claim 1 further comprising an aperture layer having a plurality of apertures and wherein the aperture layer and first sensor array of depth photosensors are arranged to form a plurality of receiver channels with each receiver channel in the plurality of receiver channels including an aperture from the plurality of apertures and a depth photosensor from the first sensor array of depth photosensors with the aperture defining the field of view of the depth photosensor in the receiver channel.

13. The electronically scanning optical system of claim 1 wherein an activation of the image photosensors is temporally centered with respect to a respective firing of the corresponding light emitters.

14. A solid state optical system comprising:
an emitter array comprising a plurality of light emitters configured to emit discrete beams of light at an operating wavelength into a field external to the optical system according to an illumination pattern;
a lidar sensor array comprising a first plurality of photosensors operable to detect light emitted from the emitter array and reflected back from a field external to the solid state optical system, wherein each photosensor in the first plurality of photosensors has a discrete field of view in the field that is non-overlapping beyond a threshold distance from the optical system with the fields of view of the other photosensors in the first plurality of photosensors and wherein the field of view of the lidar sensor array substantially matches, in size and geometry across a range of distances from the system the illumination pattern of the emitter array;
an image sensor array comprising a second plurality of photosensors configured to detect ambient light in the field, wherein the discrete fields of view of each photosensor in the first plurality of photosensors defines a field of view of the lidar sensor array and wherein a field of view of the image sensor array encompasses the field of view of the lidar sensor array;
an emitter controller coupled to the emitter array and configured to activate every emitter in the plurality of light emitters in each emission cycle by activating a subset of the plurality of light emitters at a time;
a lidar sensor controller coupled to the lidar sensor array and configured to synchronize a readout of individual photosensors within the first plurality of photosensors concurrently with a firing of corresponding light emitters in the emitter array such that each light emitter in the emitter array can be activated and each photosensor in the first sensor array can be readout through the emission cycle; and
an image sensor controller coupled to the image sensor array and configured to readout at least a portion of the image sensor array having a field of view that overlaps with a field of view of the emitter array to capture an image that is representative of the field during the emission cycle.

15. The solid state optical system of claim 14 wherein in each instance in which the emitter controller activates a subset of the plurality of light emitters, the image sensor controller activates and reads out from a subset of photosensors in the second plurality of photosensors that share the field o

Assignees

• Ouster Inc

Inventors

• Pacala Angus

Classifications

• G01S17/86 Primary

  Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders · CPC title

• G01S7/484 Primary

  Transmitters · CPC title

• G01S7/4863

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

• G01S17/42

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

• H03K3/42

  by the use, as active elements, of opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled · CPC title