System and method for ground plane detection
Improved processing of sensor data (e.g., LiDAR data) can be used to distinguish between free space and objects/hazards. Autonomous vehicles can use such information for performing autonomous driving and/or parking operations. LiDAR data can include a plurality of range measurements (e.g., forming a 3D point cloud). Each of the range measurements can correspond to a respective LiDAR channel and azimuth angle. The processing of LiDAR data can include identifying one or more of the plurality of range measurements as ground points or non-ground points based on one or more point criteria. The one or more point criteria can include a ground projection criterion and an angular variation criterion.
1. A system configured to be incorporated into a vehicle, the system comprising:
one or more light detection and ranging (LiDAR) sensors comprising one or more LiDAR channels; and
one or more processors coupled to the one or more LiDAR sensors, the processor configured to process ranging data from the one or more LiDAR sensors, the ranging data including a plurality of paths, each respective path comprising a range measurement for each of the one or more LiDAR sensor at an azimuth angle of the respective path, wherein processing the ranging data comprises:
selecting a first subset of paths of the plurality of paths to include a pair of non-adjacent paths separated by a distance;
selecting a second subset of paths of the plurality of paths;
for each respective path of the first subset of paths:
decomposing the range measurements into height projection data and ground projection data,
identifying range measurements as ground points or non-ground points based on one or more point criteria by computing differentials of the height projection data and differentials of the ground projection data between adjacent LiDAR channels, wherein the one or more point criteria comprise a ground projection criterion and an angular variation criterion;
for each respective path of the second subset of paths, foregoing decomposing the range measurements into height projection data and ground projection data, and foregoing identifying the range measurements as ground points or non-ground points; and
in the event that the pair of non-adjacent paths are identified as ground points, selecting the first subset of paths to include one or more intervening paths between the pair of non-adjacent path;
in the event that the pair of non-adjacent paths are identified as non-ground points, selecting the second subset of paths to include the one or more intervening paths between the pair of non-adjacent paths.
2. The system of claim 1 , wherein the one or more processors are further configured to:
generate navigation commands for the vehicle in accordance with the identification of a subset of the ranging data as ground points or non-ground points.
3. The system of claim 1 , wherein the ground projection criterion is satisfied for a range measurement when the ground differential is greater than zero.
4. The system of claim 1 , wherein identifying the range measurements as ground points or non-ground points comprises, for each respective path:
computing angular variations along the respective path using the differentials of the height projection data and the differentials of the ground projection data.
5. The system of claim 4 , wherein the angular variation criterion is satisfied when an angular variation along the path is less than an angular variation threshold.
6. The system of claim 1 , wherein the one or more processors are further configured to:
identify free space based on the minimum distance along one or more paths to one or more non-ground points.
7. A method comprising:
processing ranging data from one or more light detection and ranging (LiDAR) sensors, the LiDAR sensors comprising one or more LiDAR channels, the ranging data including a plurality of paths, each respective path comprising a range measurement for each of the one or more LiDAR sensor at an azimuth angle of the respective path, wherein processing the ranging data comprises:
selecting a first subset of paths of the plurality of paths to include a pair of non-adjacent paths separated by a distance;
selecting a second subset of paths of the plurality of paths;
for each respective path of the first subset of paths:
decomposing the range measurements into height projection data and ground projection data;
identifying range measurements as ground points or non-ground points based on one or more point criteria by computing differentials of the height projection data and differentials of the ground projection data between adjacent LiDAR channels, wherein the one or more point criteria comprise a ground projection criterion and an angular variation criterion;
for each respective path of the second subset of paths, foregoing decomposing the range measurements into height projection data and ground projection data, and foregoing identifying the range measurements as ground points or non-ground points;
in the event that the pair of non-adjacent paths are identified as ground points, selecting the first subset of paths to include one or more intervening paths between the pair of non-adjacent paths; and
in the event that the pair of non-adjacent paths are identified as non-ground points, selecting the second subset of paths to include the one or more intervening paths between the pair of non-adjacent paths.
8. The method of claim 7 , the method further comprising:
generating navigation commands for the vehicle in accordance with the identification of a subset of the ranging data as ground points or non-ground points.
9. The method of claim 7 , wherein the ground projection criterion is satisfied for a range measurement when the ground differential is greater than zero.
10. The method of claim 7 , wherein identifying the plurality of range measurements as ground points or non-ground points comprises, for each respective path: computing angular variations along the respective path using the differentials of the height projection data and the differentials of the ground projection data.
11. The method of claim 10 , wherein the angular variation criterion is satisfied when an angular variation along the path is less than an angular variation threshold.
12. The method of claim 7 , the method further comprising:
identifying free space based on the minimum distance along one or more paths to one or more non-ground points.
13. A non-transitory computer readable storage medium storing instructions, which when executed by one or more processors, cause the one or more processors to perform a method, the method comprising:
processing ranging data from one or more light detection and ranging (LiDAR) sensors, the LiDAR sensors comprising one or more LiDAR channels, the ranging data including a plurality of paths, each respective path comprising a range measurement for each of the one or more LiDAR sensor at an azimuth angle of the respective path, wherein processing the ranging data comprises:
selecting a first subset of paths of the plurality of paths to include a pair of non-adjacent paths separated by a distance;
selecting a second subset of paths of the plurality of paths;
for each respective path of the first subset of paths:
decomposing the range measurements into height projection data and ground projection data;
identifying the range measurements as ground points or non-ground points based on one or more point criteria by computing differentials of the height projection data and differentials of the ground projection data between adjacent LiDAR channels, wherein the one or more point criteria comprise a ground projection criterion and an angular variation criterion;
for each respective path of the second subset of paths, foregoing decomposing the range measurements into height projection data and ground projection data, and foregoing identifying the range measurements as ground points or non-ground points;
in the event that the pair of non-adjacent paths are identified as ground points, selecting the first subset of paths to include one or more intervening paths between the pair of non-adjacent paths; and
in the event that the pair of non-adjacent paths are identified as non-ground points, selecting the second subset of paths to include the one or more intervening paths between the pair of non-adjacent paths.
14. The system of claim 1 , wherein processing the range data further comprises:
determining a direction of navigation of the vehicle, and
selecting the first subset of paths based on a comparison of the azimuth angle of each respective path of the plurality of paths to the direction of navigation.
15. The system of claim 7 , wherein processing the range data further comprises:
determining a direction of navigation of the vehicle, and
selecting the first subset of paths based on a comparison of the azimuth angle of each respective path of the plurality of paths to the direction of navigation.