Method for identification of a noise point used for LiDAR, and LiDAR system
A method for processing a point cloud generated by a light detection and ranging system, includes: receiving a first measurement generated by the light detection and ranging system; retrieving a plurality of second measurements that are adjacent to the first measurement; calculating a first parameter by using distances of the first measurement and the plurality of the second measurements, the first parameter indicating a degree of continuum of the first measurement relative to the plurality of the second measurements; and determining whether the first measurement represents a measurement of noises by using the first parameter.
1. A method for processing a point cloud generated by a light detection and ranging system, comprising:
receiving a first measurement generated by the light detection and ranging system;
retrieving a plurality of second measurements that are adjacent to the first measurement;
calculating a first parameter by using a distance of the first measurement and distances of the plurality of the second measurements, the first parameter indicating a degree of continuum of the first measurement relative to the plurality of the second measurements; and
determining whether the first measurement represents a measurement of noises by using the first parameter.
2. The method according to claim 1 , wherein the determining comprises comparing the first parameter with an adjustable threshold having a threshold value that is adjusted in accordance with the distance of the first measurement.
3. The method according to claim 2 , wherein the threshold value increases with the distance of the first measurement.
4. The method according to claim 1 , wherein the calculating further comprises calculating a second parameter by using reflectivity of the first measurement and the plurality of the second measurements, and the determining comprises determining whether the first measurement represents the measurement of noises by using both the first parameter and the second parameter.
5. The method according to claim 1 , wherein the determining further comprises determining whether the first measurement represents a measurement of a snowflake or a raindrop.
6. The method according to claim 5 , wherein the calculating further comprises calculating a third parameter indicating a noise level of the first measurement, and the determining comprises determining whether the first measurement represents the snowflake or the raindrop by using both the first parameter and the third parameter.
7. The method according to claim 5 , wherein the calculating further comprises calculating a fourth parameter indicating a number of echoes detected during generation of the first measurement, and the determining comprises determining whether the first measurement represents the snowflake or the raindrop by using both the first parameter and the fourth parameter.
8. The method according to claim 5 , wherein the determining comprises determining whether the first measurement represents the snowflake or the raindrop by using the distance of the first measurement, reflectivity of the first measurement, and a noise level of the first measurement.
9. The method according to claim 1 , wherein the calculating further comprises calculating a plurality of parameters indicating reflectivity, a distance, a noise level, or a number of echoes of the first measurement and calculating a confidence level by using the plurality of the parameters, the confidence level indicating whether the first measurement represents the measurement of noises.
10. The method according to claim 9 , wherein each one of the plurality of the parameters and the first parameter is assigned a weight, and the confidence level represents an aggregated value of weights assigned to the plurality of the parameters and the first parameter.
11. The method according to claim 10 , further comprising:
adjusting the weight assigned to each of the plurality of the parameters and the first parameter according to a weather condition of the first measurement.
12. The method according to claim 1 , further comprising:
filtering out, in real-time, the first measurement from an output of the light detection and ranging system when the first measurement is determined to represent the measurement of noises.
13. A light detection and ranging system for generating a point cloud, comprising:
a plurality of laser emitters for emitting laser beams;
a plurality of laser detectors for detecting backscattered laser beams emitted by the plurality of the laser emitters; and
one or more processors for generating a measurement of distance based on signals output by the plurality of the laser detectors; and for identifying measurements of noises, wherein the one or more processors are configured to:
receive a first measurement generated by the light detection and ranging system;
retrieve a plurality of second measurements that are adjacent to the first measurement;
calculate a first parameter by using a distance of the first measurement and distances of the plurality of the second measurements, the first parameter indicating a degree of continuum of the first measurement relative to the plurality of the second measurements; and
determine whether the first measurement represents a measurement of noises by using the first parameter.
14. The light detection and ranging system according to claim 13 , wherein the one or more processors are further configured to compare the first parameter with an adjustable threshold having a threshold value that is adjusted in accordance with the distance of the first measurement.
15. The light detection and ranging system according to claim 14 , wherein the threshold value increases with the distance of the first measurement.
16. The light detection and ranging system according to claim 13 , wherein the one or more processors are further configured to calculate a second parameter by using reflectivity of the first measurement and the plurality of the second measurements, and determine whether the first measurement represents the measurement of noises by using both the first parameter and the second parameter.
17. The light detection and ranging system according to claim 13 , wherein the one or more processors are further configured to determine whether the first measurement represents a measurement of a snowflake or a raindrop.
18. The light detection and ranging system according to claim 17 , wherein the one or more processors are further configured to calculate a third parameter indicating a noise level of the first measurement, and determine whether the first measurement represents the snowflake or the raindrop by using both the first parameter and the third parameter.
19. The light detection and ranging system according to claim 17 , wherein the one or more processors are further configured to calculate a fourth parameter indicating a number of echoes detected during generation of the first measurement, and determine whether the first measurement represents the snowflake or the raindrop by using both the first parameter and the fourth parameter.
20. The light detection and ranging system according to claim 17 , wherein the one or more processors are further configured to determine whether the first measurement represents the snowflake or the rain drop by using the distance of the first measurement, reflectivity of the first measurement, and a noise level of the first measurement.
21. The light detection and ranging system according to claim 13 , wherein the one or more processors are further configured to calculate a plurality of parameters indicating reflectivity, a distance, a noise level, or a number of echoes of the first measurement and calculate a confidence level by using the plurality of parameters, the confidence level indicating whether the first measurement represents the measurement of noises.
22. The light detection and ranging system according to claim 21 , wherein each one of the plurality of the parameters and the first parameter is assigned a weight, and the confidence level represents an aggregated value of weights assigned to the plurality of the parameters and the first parameter.
23. The light detection and ranging system according to claim 22 , further comprising:
a weather sensor configured to detect a weather condition of the first measurement,
wherein the one or more processors are further configured to adjust the weight assigned to each of the plurality of the parameters and the first parameter according to a weather condition of the first measurement.
24. The light detection and ranging system according to claim 13 , further comprising:
a filtering circuit configured to filter out, in real-time, the first measurement from an output of the light detection and ranging system when the first measure is determined to represent the measurement of noises.
25. The light detection and ranging system according to claim 24 , further comprising:
a weather sensor configured to detect a weather condition of the first measurement; and
the one or more processors are further configured to control an activation of the filtering circuit depending on the weather condition.