Lidar system with improved scanning speed for high-resolution depth mapping
A lidar system may have a light source configured to emit a pulse of light and a scanner that scans a field of view of the light source in a forward-scanning direction across a plurality of pixels located downrange from the lidar system. The scanner can direct the pulse of light toward the second pixel and scan a field of view of a first detector. The first-detector field of view can be offset from the light-source field of view in a direction opposite the forward-scanning direction. When the pulse is emitted, the first-detector field of view can at least partially overlap the first pixel and the light-source field of view can at least partially overlap the second pixel. The first detector can be configured to detect a portion of the pulse of light scattered by a target located at least partially within the second pixel.
1. A lidar system comprising:
a light source configured to emit a pulse of light;
a scanner configured to:
scan a field of view of the light source in a forward-scanning direction across a plurality of pixels located downrange from the lidar system, wherein the plurality of pixels comprises a first pixel and a second pixel, wherein the second pixel is located adjacent to the first pixel along the forward-scanning direction;
direct the pulse of light toward the second pixel; and
scan a field of view of a first detector of the lidar system, wherein:
the first-detector field of view is scanned in the forward-scanning direction across the plurality of pixels; and
the first-detector field of view is offset from the light-source field of view in a direction opposite the forward-scanning direction,
wherein, when the pulse is emitted:
the first-detector field of view at least partially overlaps the first pixel; and
the light-source field of view at least partially overlaps the second pixel; and
the first detector, wherein the first detector is configured to detect a portion of the pulse of light scattered by a target located at least partially within the second pixel.
2. The lidar system of claim 1 , further comprising a processor configured to determine a distance from the lidar system to the target based at least in part on a time of flight of the pulse of light.
3. The lidar system of claim 1 , wherein if the distance from the lidar system to the target corresponds to a maximum range of the lidar system, then, when the first detector detects the portion of the pulse of light, the first-detector field of view overlaps substantially all of the second pixel.
4. The lidar system of claim 1 , wherein if the target is a close-range target located within 20% of a maximum range of the lidar system, then, when the first detector detects the portion of the pulse of light, the first-detector field of view overlaps less than or equal to 20% of the second pixel.
5. The lidar system of claim 1 , wherein if the target is a midrange target located between 20% and 80% of a maximum range of the lidar system, then, when the first detector detects the portion of the pulse of light, the first-detector field of view overlaps between 20% and 80% of the second pixel.
6. The lidar system of claim 1 , wherein if the target is located a distance greater than or equal to 80% of a maximum range of the lidar system, then, when the first detector detects the portion of the pulse of light, the first-detector field of view overlaps greater than or equal to 80% of the second pixel.
7. The lidar system of claim 1 , wherein an angular size of the first-detector field of view is substantially equal to an angular size of the light-source field of view.
8. The lidar system of claim 1 , wherein the second pixel being located adjacent to the first pixel along the forward-scanning direction corresponds to the light-source field of view beginning to scan across the first pixel prior to scanning across the second pixel.
9. The lidar system of claim 1 , wherein a time for the first detector field of view to scan a width of one pixel is approximately equal to a round-trip time for a maximum range of the lidar system.
10. The lidar system of claim 1 , wherein a time for the light-source field of view to scan a width of one pixel is approximately equal to a round-trip time for a maximum range of the lidar system.
11. The lidar system of claim 1 , wherein the first-detector field of view being offset from the light-source field of view in the direction opposite the forward-scanning direction is such that the first-detector field of view is aligned with the second pixel at a time after the pulse of light is emitted that corresponds to a round-trip time for a maximum range of the lidar system.
12. The lidar system of claim 1 , wherein:
the first-detector field of view is aligned with the second pixel at a time after the pulse of light is emitted that corresponds to a round-trip time for a maximum range of the lidar system; and
the light source is further configured to emit another pulse of light at a time after the first-detector field of view is aligned with the second pixel.
13. The lidar system of claim 1 , further comprising a second detector, wherein a field of view of the second detector is offset from the light-source field of view in the forward-scanning direction.
14. The lidar system of claim 13 , wherein, when the pulse is emitted, the second-detector field of view overlaps less than or equal to 20% of the second pixel.
15. The lidar system of claim 13 , wherein the scanner is further configured to:
scan the light-source field of view in a reverse-scanning direction corresponding to the direction opposite the forward-scanning direction; and
scan the second-detector field of view in the reverse-scanning direction.
16. The lidar system of claim 15 , wherein:
the light source is further configured to emit an additional pulse of light while the scanner is scanning the light-source field of view and the second-detector field of view in the reverse-scanning direction; and
the second detector is configured to detect a portion of the additional pulse of light which is scattered by a target located downrange from the lidar system.
17. The lidar system of claim 15 , wherein:
the forward-scanning direction corresponds approximately to a left-to-right direction; and
the reverse-scanning direction corresponds approximately to a right-to-left direction.
18. A method comprising:
emitting, by a light source of a lidar system, a pulse of light;
scanning a field of view of the light source in a forward-scanning direction across a plurality of pixels located downrange from the lidar system, wherein the plurality of pixels comprises a first pixel and a second pixel, wherein the second pixel is located adjacent to the first pixel along the forward-scanning direction;
directing the pulse of light toward the second pixel;
scanning a field of view of a first detector of the lidar system, wherein:
the first-detector field of view is scanned in the forward-scanning direction across the plurality of pixels; and
the first-detector field of view is offset from the light-source field of view in a direction opposite the forward-scanning direction, wherein, when the pulse is emitted:
the first-detector field of view at least partially overlaps the first pixel; and
the light-source field of view at least partially overlaps the second pixel; and
detecting a portion of the pulse of light scattered by a target located at least partially within the second pixel.
19. The method of claim 18 , further comprising determining a distance from the lidar system to the target based at least in part on a time of flight of the pulse of light.
20. The method of claim 18 , further comprising:
scanning the light-source field of view in a reverse-scanning direction corresponding to the direction opposite the forward-scanning direction;
scanning a field of view of a second detector of the lidar system in the reverse-scanning direction, wherein the second-detector field of view is offset from the light-source field of view in the forward-scanning direction.