Optical system for collecting distance information within a field

Patent metadata

Field	Value
Publication number	US-11422236-B2
Application number	US-202117552303-A
Country	US
Kind code	B2
Filing date	Dec 15, 2021
Priority date	Aug 24, 2016
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

Optical systems and methods for collecting distance information are disclosed. An example optical system includes a first transmitting optic, a plurality of illumination sources, a pixel array comprising at least a first column of pixels and a second column of pixels, each pixel in the first column of pixels being offset from an adjacent pixel in the first column of pixels by a first pixel pitch, the second column of pixels being horizontally offset from the first column of pixels by the first pixel pitch, the second column of pixels being vertically offset from the first column of pixels by a first vertical pitch; and a set of input channels interposed between the first transmitting optic and the pixel array.

First claim

What is claimed is:

1. An optical system for collecting distance information, the optical system comprising:
an optical imaging transmit module comprising a bulk transmitting optic and an illumination source comprising a plurality of optical emitters arranged behind the bulk transmitting optic, wherein each optical emitter in the plurality of optical emitters can project light at a nominal wavelength through the bulk transmitting optic and into a field ahead of the optical system;
an optical imaging receive module comprising a bulk receiving optic and a plurality of pixels arranged behind the bulk receiving optic, wherein each pixel in the plurality of pixels comprises a plurality of single photon avalanche diodes (SPADs) and wherein the plurality of pixels includes a first set of pixels arranged in a first column and a second set of pixels arranged in a second column horizontally and vertically offset from the first column; and
an actuator operable to rotate the optical imaging receive module about a vertical axis over a plurality of scan cycles in which, during each scan cycle, the optical imaging receive module is rotated 360 degrees such that each pixel in the plurality of pixels traverses a unique circular path parallel to and vertically offset from a unique circular path traversed by every other pixel in the optical system;
wherein the optical system generates, for each of a plurality of arcuate sampling positions within one scan cycle, data that represents distances from the optical system to external surfaces in the field 360 degrees around the optical system.

2. The optical system of claim 1 further comprising an optical filter disposed in front of each pixel in the plurality of pixels and operable to allow a set of wavelengths of light, including the nominal wavelength, to pass through the optical filter while blocking light outside the set of wavelengths of light from reaching the plurality of pixels.

3. The optical system of claim 2 wherein the optical filter comprises a fused silica substrate having a coating formed thereon.

4. The optical system of claim 1 wherein the actuator includes an electric motor with an optical encoder and the optical system implements closed-loop feedback controls to maintain a rotational speed of the electric motor at a specific frequency based on outputs of the optical encoder.

5. The optical system of claim 1 wherein the bulk transmitting optic and the bulk receiving optic are each image-space telecentric lenses and the bulk transmitting optic is adjacent to an offset laterally from the bulk receiving optic.

6. The optical system of claim 1 wherein the optical imaging receive module comprises a plurality of micro-lenses disposed between the bulk receiving optic and the plurality of pixels.

7. The optical system of claim 1 wherein the circular paths traversed by pixels from the second set of pixels in the second column are interleaved with the circular paths traversed by pixels from the first set of pixels in the first column.

8. The optical system of claim 1 wherein the optical imaging receive module further comprises a plurality of apertures and a stop region disposed between adjacent apertures in the plurality of apertures, wherein the plurality of apertures includes a first aperture and a second aperture horizontally and vertically offset from the first aperture, the first set of pixels includes a first pixel disposed in a first optical path that extends through the first aperture and the second set of pixels includes a second pixel disposed in a second optical path that extends through the second aperture.

9. The optical system of claim 1 wherein the optical system implements time of flight techniques to determine distances from the optical system to external surfaces in the field.

10. An optical system for collecting distance information, the optical system comprising:
an output circuit comprising a bulk transmitting optic and an illumination source configured to output light at a nominal wavelength, the illumination source including a plurality of optical emitters arranged behind the bulk transmitting optic, wherein each optical emitter can project an illuminating beam at the nominal wavelength through the bulk transmitting optic and into a field ahead of the optical system;
an input circuit comprising a bulk receiving optic disposed adjacent to the bulk transmitting optic and a plurality of pixels arranged behind the bulk receiving optic, wherein each pixel in the plurality of pixels comprises a plurality of single photon avalanche diodes (SPADs) and wherein the plurality of pixels includes a first set of pixels arranged in a first column and a second set of pixels arranged in a second column horizontally and vertically offset from the first column; and
an electric motor configured to rotate the input circuit about a vertical axis over a plurality of scan cycles in which, during each scan cycle, the input circuit is rotated 360 degrees such that each pixel in the plurality of pixels traverses a unique circular path parallel to and vertically offset from a unique circular path traversed by each other pixel in the optical system;
wherein the optical system collects data from each pixel in the plurality of pixels at a plurality of different arcuate sampling position as the input circuit is rotated through 360 degrees during each scan cycle.

11. The optical system of claim 10 wherein each pixel in the plurality of pixels has a field of view that is non-overlapping with fields of view of all other pixels in the plurality of pixels, and the illumination source is configured to project illuminating beams into the field ahead of the optical system according to an illumination pattern where each beam in the illumination pattern is coincident with a field of view of one pixel in the plurality of pixels.

12. The optical system of claim 11 wherein each scan cycle includes a plurality of sampling periods and, during each sampling period in the plurality of sampling periods, the optical system activates each emitter in the plurality of optical emitters to project the illumination pattern and determines a number of SPADs in each pixel that recorded an incident photon since a previous sampling period.

13. The optical system of claim 12 wherein, during each sampling period of the plurality of sampling periods within one scan cycle, the optical system determines distances to objects in the field based on a difference between a time at which an optical emitter is fired and a time at which incident photons are detected at a pixel having a field of view that overlaps with a field of view of the fired optical emitter.

14. The optical system of claim 10 wherein
the input circuit further comprises a plurality of apertures and stop region disposed between adjacent apertures in the plurality of apertures, wherein the plurality of apertures comprises a first aperture, a second aperture horizontally and vertically offset from the first aperture, a third aperture aligned vertically with the first aperture and vertically offset from the first and second apertures; and a fourth aperture aligned vertically with the second aperture and vertically offset from the first, second and third apertures;
the first set of pixels includes a first pixel and a third pixel and the second set of pixels includes a second pixel and a fourth pixel;
the plurality of optical emitters includes a first emitter, a second emitter, a third emitter and a fourth emitter; and
the first pixel has a field of view coincident with the first emitter such that the first pixel is operable to detect photons emitted from the first emitter and receive

Assignees

• Ouster Inc

Inventors

• Pacala Angus
• Frichtl Mark
• SHU Marvin
• Younge Eric

Classifications

• G01S17/89 Primary

  for mapping or imaging · CPC title

• G01S17/08

  for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) · CPC title

• G01S7/4817 Primary

  relating to scanning · CPC title

• G01S7/4816 Primary

  of receivers alone · CPC title

• G01S7/4915

  Time delay measurement, e.g. operational details for pixel components (signal extraction and conditioning G01S7/493); Phase measurement · CPC title