Optical system for collecting distance information within a field
An optical system for collecting distance information within a field is provided. The optical system may include lenses for collecting photons from a field and may include lenses for distributing photons to a field. The optical system may include lenses that collimate photons passed by an aperture, optical filters that reject normally incident light outside of the operating wavelength, and pixels that detect incident photons. The optical system may further include illumination sources that output photons at an operating wavelength.
1. An optical system for collecting distance information, the optical system comprising:
a bulk transmitting optic;
a plurality of optical emitters arranged behind the bulk transmitting optic and configured to output electromagnetic radiation of an operating wavelength through the bulk transmitting optic into a field external to the optical system according to an illumination pattern that comprises a plurality of non-overlapping emission regions;
a bulk imaging optic disposed adjacent to the bulk transmitting optic;
a plurality of pixels arranged behind the bulk imaging optic, wherein each pixel in the plurality of pixels has a field of view coincident with an emission region of a corresponding optical emitter in the plurality of optical emitters and each pixel comprises a plurality of single photon avalanche diodes (SPADs) operable to detect photons emitted from its corresponding optical emitter and received through the bulk imaging optic after being reflected from surfaces within the field; and
an optical filter disposed in an optical path of the plurality of pixels, the optical filter configured to allow a set of wavelengths of electromagnetic radiation, including the operating wavelength, to pass through the optical filter while blocking electromagnetic radiation outside the set of wavelengths from reaching the plurality of pixels.
2. The optical system according to claim 1 wherein, the optical system is configured to collect three-dimensional distance data based on times between transmission of illuminating beams from the plurality of optical emitters and detection of photons from the illuminating beams by the plurality of pixels.
3. The optical system according to claim 1 wherein the plurality of optical emitters are arranged in a first arrangement and the plurality of pixels are arranged in a second arrangement, proportional to the first arrangement.
4. The optical system according to claim 1 wherein bulk transmitting optic and the bulk imaging optic are each image-space telecentric bulk optics.
5. The optical system according to claim 1 further comprising a rotation mechanism configured to rotate the optical system about a rotational axis.
6. The optical system according to claim 1 further comprising an aperture layer disposed between the bulk imaging optic and the plurality of pixels and comprising a plurality of apertures separated by a stop region.
7. The optical system according to claim 6 wherein the aperture layer comprises a thin opaque structure.
8. The optical system according to claim 6 wherein:
the plurality of apertures comprises a first aperture, a second aperture, a third aperture, and a fourth aperture;
the plurality of pixels comprises a first pixel, a second pixel, a third pixel and a fourth pixel; and
the optical system includes a first optical path that extends between the bulk imaging optic and the first pixel through the first aperture, a second optical path that extends between the bulk imaging optic and the second pixel through the second aperture, a third optical path that extends between the bulk imaging optic and the third pixel through the third aperture, and a fourth optical path that extends between the bulk imaging optic and the fourth pixel through the fourth aperture.
9. The optical system according to claim 6 wherein the aperture layer is arranged along a plane coincident with a focal plane of the bulk imaging optic.
10. The optical system according to claim 1 further comprising a signal processing circuit coupled to the plurality of pixels.
11. The optical system according to claim 10 wherein the signal processing circuit is configured to count incident photons within a sampling period for the plurality of pixel detectors.
12. The optical system according to claim 1 wherein the plurality of optical emitters comprises a plurality of vertical-cavity surface-emitting lasers (VCSELs) mounted on a common substrate.
13. The optical system according to claim 1 wherein each optical emitter in the plurality of optical emitters comprises a single vertical-cavity surface-emitting lasers (VCSEL).
14. An optical system for collecting distance information, the optical system comprising:
a bulk transmitting optic;
a plurality of optical emitters arranged behind the bulk transmitting optic and configured to output electromagnetic radiation of an operating wavelength into a plurality of non-overlapping emission regions, each emission region representing a spot in a field ahead of the optical system;
a bulk imaging optic;
a plurality of pixels arranged behind the bulk imaging optic and corresponding in number to the plurality of optical emitters, wherein each pixel in the plurality of pixels is paired with a different optical emitter in the plurality of optical emitters and has a field of view coincident with an emission region of its paired optical emitter and wherein each pixel comprises a plurality of single photon avalanche diodes (SPADs) operable to detect photons emitted from its paired optical emitter and received through the bulk imaging optic after being reflected from surfaces within the field; and
an optical filter disposed in an optical path of the plurality of pixels, the optical filter configured to allow a set of wavelengths of electromagnetic radiation, including the operating wavelength, to pass through the optical filter while blocking electromagnetic radiation outside the set of wavelengths from reaching the plurality of pixels;
wherein, the optical system is configured to collect distance data based on times between transmission of beams of electromagnetic radiation from the plurality of optical emitters and detection of photons from the beams by the plurality of pixels.
15. The optical system according to claim 14 wherein the plurality of optical emitters are configured to illuminate substantially only emission regions in the field that can be detected by the plurality of pixels in the optical system.
16. The optical system according to claim 14 wherein each pixel is operable to output a signal corresponding to a count of photons incident on the pixel within one sampling period.
17. The optical system according to claim 14 further comprising an aperture layer disposed between the bulk imaging optic and the plurality of pixels and comprising a plurality of apertures separated by a stop region.
18. The optical system according to claim 17 wherein each aperture in the plurality of apertures is axially aligned with a different pixel in the plurality of pixels and defines a field of view for its aligned pixel.
19. The optical system according to claim 14 wherein the bulk transmitting optic and the bulk imaging optic are each image-space telecentric optics.
20. A lidar system comprising:
a bulk transmitting optic;
a plurality of optical emitters arranged behind the bulk transmitting optic and configured to output illuminating beams of an operating wavelength through the bulk transmitting optic and into a field ahead of the lidar system according to an illumination pattern that comprises a plurality of non-overlapping emission regions within the field, wherein each optical emitter in the plurality of optical emitters outputs an illuminating beam into a unique one of the emission regions within the illumination pattern;
a telecentric bulk imaging optic;
a plurality of receiver channels having non-overlapping fields of view that substantially match, in size and geometry across a range of distances from the lidar system, the illumination pattern of the plurality of optical emitters, wherein each receiver channel in the plurality of receiver channels is paired with an optical emitter in the plurality of optical emitters such that a field of view for the receiver channel is coincident with the emission region of its paired optical emitter, and wherein each receiver channel includes one pixel arranged behind the bulk imaging optic and comprising a plurality of single photon avalanche diodes (SPADs) operable to detect photons emitted its paired optical emitter and received through the bulk imaging optic after being reflected from surfaces within the field; and
an optical filter disposed in an optical path of each pixel in the plurality of receiver channels, the optical filter configured to allow a band of wavelengths of electromagnetic radiation, including the operating wavelength, to pass through the optical filter while blocking electromagnetic radiation outside the band of wavelengths from reaching the pixels;
wherein, the lidar system collects three-dimensional distance data based on times between transmission of illuminating beams from the plurality of optical emitters and detection of photons from the illuminating beans by the plurality of pixels.
21. The lidar system according to claim 20 wherein each pixel functions to output a signal corresponding to a count of photons incident on the pixel within one sampling period.
22. The lidar system according to claim 20 wherein the bulk transmitting optic and the bulk imaging optic are each image-space telecentric optics.
23. The lidar system according to claim 20 further comprising an aperture layer disposed between the bulk imaging optic and the plurality of pixels and comprising a plurality of apertures separated from each other by a non-transparent stop region.
24. The lidar system according to claim 20 wherein each optical emitter in the plurality of optical emitters comprises a single vertical-cavity surface-emitting laser (VCSEL).
25. The lidar system according to claim 20 wherein the plurality of optical emitters are configured to illuminate substantially only emission regions in the field that can be detected by the plurality of pixels in the lidar system.