System and method for angle measurement
A system for generating a ground truth dataset for motion planning is disclosed. The system includes: a collecting module configured to collect LiDAR scans; a detecting module configured to detect two pose estimates that are closest to LiDAR scan accusation time; a determining module configured to determine LiDAR's poses based on an interpolation; and a transforming module configured to transform LiDAR raw scans into undistorted LiDAR scans.
1. A method of measuring an angle and an angular velocity between a first portion of a moving object and a second portion of the moving object comprising:
(i) generating, using a light detection and ranging (LiDAR) device or a scanning laser rangefinder, a point cloud representing information on a relative position of a front edge of the second portion with respect to the first portion;
(ii) calculating an angle between the first portion and the second portion from the point cloud;
(iii) repeating steps (i) and (ii) to generate a plurality of calculated angles;
(iv) calculating a weighted moving average from the plurality of calculated angles, wherein a later calculated angle of the plurality of calculated angles has a higher weight than an earlier calculated angle of the plurality of calculated angles; and
(v) calculating an angular velocity from the plurality of calculated angles.
2. The method according to claim 1 wherein calculating the angle between the first portion and the second portion comprises filtering the point cloud with a predetermined threshold range.
3. The method according to claim 2 wherein points of the point cloud located outside the predetermined threshold range of distances are filtered out.
4. The method according to claim 3 wherein the predetermined threshold range is between 1 meter and 2.5 meters.
5. The method according to claim 1 wherein calculating the angle between the first portion and the second portion comprises performing coordinate change on the point cloud.
6. The method according to claim 5 wherein performing coordinate change comprises turning the point cloud from polar coordinate into Cartesian coordinate.
7. The method according to claim 1 wherein calculating the angle between the first portion and the second portion comprises performing linear fitting on the point cloud.
8. The method according to claim 7 wherein performing linear fitting comprises a least squares method.
9. The method according to claim 1 wherein weights of the plurality of calculated angles incrementally increase along with an order of the generation of the plurality of calculated angles.
10. The method according to claim 1 wherein the plurality of calculated angles are weighted linearly.
11. The method according to claim 1 wherein the angular velocity is calculated from the weighted moving average.
12. A system for measuring an angle and an angular velocity between a first portion of a moving object and a second portion of the moving object, the system comprising:
an internet server, comprising:
an I/O port, configured to transmit and receive electrical signals to and from a client device;
a memory;
a processor; and
one or more programs stored in the memory and configured for execution by the processor, the one or more programs comprising instructions for:
(i) generating, using a light detection and ranging (LiDAR) device or a scanning laser rangefinder, a point cloud representing information on a relative position of a front edge of the second portion with respect to the first portion;
(ii) calculating an angle between the first portion and the second portion from the point cloud;
(iii) repeating steps (i) and (ii) to generate a plurality of calculated angles;
(iv) calculating a weighted moving average from the plurality of calculated angles, wherein a later calculated angle of the plurality of calculated angles has a higher weight than an earlier calculated angle of the plurality of calculated angles; and
(v) calculating an angular velocity from the plurality of calculated angles.
13. The system according to claim 12 wherein calculating the angle between the first portion and the second portion comprises filtering the point cloud with a predetermined threshold range.
14. The system according to claim 12 wherein calculating the angle between the first portion and the second portion comprises performing coordinate change on the point cloud.
15. The system according to claim 14 wherein performing coordinate change comprises turning the point cloud from polar coordinate into Cartesian coordinate.
16. The system according to claim 12 wherein calculating the angle between the first portion and the second portion comprises performing linear fitting on the point cloud.
17. An autonomous vehicle, comprising:
the system according to claim 12 ;
a first portion;
a second portion towed by the first portion; and
a LiDAR projecting beams from one of the first portion and the second portion toward the other one of the first portion and the second portion.
18. The system according to claim 12 wherein a scanning angle of the LiDAR is in a range of 0° to 120°.
19. The system according to claim 12 wherein an angle step of a scanning of the LiDAR is 0.35°.