2D scanning high precision LiDAR using combination of rotating concave mirror and beam steering devices
The present disclosure describes a system and method for coaxial LiDAR scanning. The system includes a first light source configured to provide first light pulses. The system also includes one or more beam steering apparatuses optically coupled to the first light source. Each beam steering apparatus comprises a rotatable concave reflector and a light beam steering device disposed at least partially within the rotatable concave reflector. The combination of the light beam steering device and the rotatable concave reflector, when moving with respect to each other, steers the one or more first light pulses both vertically and horizontally to illuminate an object within a field-of-view; obtain one or more first returning light pulses, the one or more first returning light pulses being generated based on the steered first light pulses illuminating an object within the field-of-view, and redirects the one or more first returning light pulses.
1. A light detection and ranging (LiDAR) system for use with a vehicle, the LiDAR system comprising:
a light source configured to provide one or more light beams;
a beam steering apparatus optically coupled to the light source, the beam steering apparatus comprising:
a polygon structure comprising a plurality of reflective facets, wherein the plurality of reflective facets are not all orthogonal with respect to each other; and
a moveable mirror optically coupled to the polygon structure,
wherein the combination of the polygon structure and the moveable mirror, when moving with respect to each other, is configured to:
steer the one or more light beams vertically and horizontally to illuminate an object within a field-of-view,
receive return light generated based on the illumination of the object within the field-of-view, and
direct the return light to a detector,
and wherein the moveable mirror is configured to oscillate between two end vertical positions to obtain multiple scanlines in-between.
2. The LiDAR system of claim 1 , wherein an angle between any two adjacent reflective facets of the plurality of reflective facets is other than a 90-degree angle.
3. The LiDAR system of claim 1 , wherein the polygon structure comprises a total of more than six facets including the plurality of reflective facets and two non-reflective facets.
4. The LiDAR system of claim 3 , wherein the polygon structure is a hexahedron, septahedron, or octahedron.
5. The LiDAR system of claim 1 , wherein the polygon structure comprises a total of less than six facets.
6. The LiDAR system of claim 5 wherein the polygon structure is a pentahedron.
7. The LiDAR system of claim 5 , wherein the plurality of reflective facets are configured to be asymmetrical to facilitate one or both of offsetting vertical and horizontal scanning directions between subframes and changing an interlacing raster pattern.
8. The LiDAR system of claim 1 , wherein at least one of the plurality of reflective facets is a curved facet.
9. The LiDAR system of claim 1 , wherein the moveable mirror comprises an oscillation mirror.
10. The LiDAR system of claim 9 , wherein the oscillation mirror is operative to oscillate about a first axis and the polygon structure is operative to rotate about a second axis, wherein the combination of the oscillation mirror and the polygon structure, when moving based on their respective axes, coaxially illuminates the object using the one or more light beams and collects the return light.
11. The LiDAR system of claim 9 , wherein the oscillation mirror is a multiple facet oscillation mirror.
12. The LiDAR system of claim 1 , wherein the oscillation mirror is configured to oscillate about an axis orthogonal to an axis about which the polygon structure is configured to rotate.
13. The LiDAR system of claim 1 , wherein the one or more light beams comprise a first light beam and a second light beam, and wherein the beam steering apparatus scans the first light beam in a first range within the field-of-view and scans the second light beam in a second range within the field-of-view, the first range and the second range overlap.
14. A light detection and ranging (LiDAR) system for use with a vehicle, the LiDAR system comprising:
one or more light sources configured to generate one or more light beams;
a beam scanner configured to scan a field-of-view of the LiDAR system using the one or more light beams, the beam scanner comprising:
a rotatable polygon mirror having a block comprising a plurality of reflective surfaces, wherein at least two adjacent reflective surfaces of the rotatable polygon mirror are other than orthogonal with respect to each other, and
a pivotable planar mirror configured to oscillate between two end vertical positions to obtain multiple scanlines in-between,
wherein the beam scanner is optically coupled to the light source and is positioned to steer light vertically and horizontally to illuminate an object within the field-of-view of the LiDAR system.
15. The LiDAR system of claim 14 , further comprising a detector configured to receive return light directed by the beam scanner.
16. The LiDAR system of claim 14 , wherein the plurality of reflective surfaces comprises four or more reflective surfaces.
17. The LiDAR system of claim 14 , wherein the rotatable polygon mirror is operative to rotate about a polygon mirror axle, the polygon mirror axle extending into the rotatable polygon mirror block through two opposing non-reflective surfaces of the block.
18. The LiDAR system of claim 14 , wherein the pivotable planar mirror is pivotable about an axis orthogonal to the polygon mirror axle.
19. The LiDAR system of claim 14 , the pivotable planar mirror is operative to oscillate about a first axis and the block of the rotatable polygon mirror is operative to rotate about a second axis, the combination of the pivotable planar mirror and the block of the rotatable polygon mirror, when moving based on their respective axes, coaxially illuminates the object using the one or more light beams and collects return light.
20. The LiDAR system of claim 14 , further comprising one or more optical fibers delivering the one or more light beams to the beam scanner.
21. The LiDAR system of claim 14 , wherein:
the one or more light beams comprise a first light beam and a second light beam;
the first light beam and the second light beam are scanned by the beam scanner to define a first field-of-view and a second field-of-view, respectively,
the first field of view and the second field-of-view in combination define the field-of-view of the LiDAR system, and
the first field-of-view and the second field-of-view partially overlap to define an overlap region within the field-of-view of the LiDAR system.
22. The LiDAR system of claim 14 , wherein:
the one or more light beams comprise a first light beam and a second light beam, and
each of the first light beam and second light beam is scanned by the beam scanner to define a respective partial field-of-view of approximately 60 degrees wide in one direction.
23. The LiDAR system of claim 14 , wherein the pivotable planar mirror is positioned to receive light reflected by the rotatable polygon mirror, further wherein the pivotable planar mirror is positioned to direct light to the field-of-view.
24. A light detection and ranging (LiDAR) system for use with a vehicle, the LiDAR system comprising:
a light source operative to provide incident light;
a detector operative to receive return light;
a polygon structure optically coupled to the light source, wherein the polygon structure includes a plurality of reflective facets, wherein an angle between any two adjacent reflective facets of the plurality of reflective facets is other than a 90-degree angle; and
a moveable mirror optically coupled to the polygon structure,
wherein the polygon structure and the moveable mirror are positioned to steer light in two directions orthogonal to each other,
and wherein the moveable mirror is configured to oscillate between two end vertical positions to obtain multiple scanlines in-between.
25. The LiDAR system of claim 24 , wherein the plurality of reflective facets of the polygon structure comprises three or more facets.
26. The LiDAR system of claim 24 , wherein the moveable mirror comprises an oscillation mirror.
27. The LiDAR system of claim 24 , wherein the oscillation mirror is configured to oscillate about an axis orthogonal to an axis about which the polygon structure is configured to rotate.
28. The LiDAR system of claim 24 , wherein the moveable mirror is positioned to receive light reflected by the polygon structure, further wherein the moveable mirror is positioned to direct light to the field-of-view.