Echo signal processing method and apparatus

1 . An echo signal processing method implemented by a light detection and ranging (LiDAR) system, comprising:

receiving, in different directions, echo signals comprising a first echo signal and a second echo signal;

determining a first inflection point from the first echo signal, wherein the first inflection point is a first sampling point of the first echo signal, and wherein first amplitude values of a first left neighboring sampling point of the first inflection point and a first right neighboring sampling point of the first inflection point are less than a second amplitude value of the first inflection point;

determining a second inflection point from the second echo signal, wherein the second inflection point is a second sampling point of the second echo signal, and wherein third amplitude values of a second left neighboring sampling point of the second inflection point and a second right neighboring sampling point of the second inflection point are less than a fourth amplitude value of the second inflection point;

dividing, by a processor of the LiDAR system, a field of view (FOV) corresponding to receiving at least one echo signal into a plurality of target areas, wherein the FOV comprises a target object;

making a first determination that a first direction that the first echo signal is received and a second direction that the second echo signal is received are located in a same target area among the plurality of target areas;

separately performing, in response to the first determination, noise reduction processing on the first echo signal and the second echo signal, wherein the noise reduction processing comprises at least one of matched filtering, wavelet-domain denoising, or frequency-domain filtering;

making a second determination, in response to the first determination, that a time difference between a first moment when the first inflection point is received from the first echo signal and a second moment when the second inflection point is received from the second echo signal is less than or equal to a first preset threshold; and

combining, in response to the second determination, the first echo signal and the second echo signal to obtain a combined signal.

2 . The echo signal processing method of claim 1 , further comprising:

determining a first data segment from the first echo signal, wherein the first inflection point is in the first data segment;

determining a second data segment from the second echo signal, wherein the second inflection point is in the second data segment; and

combining the first data segment and the second data segment.

3 . The echo signal processing method of claim 2 , further comprising:

determining, as the first data segment, a first set of the first inflection point and P first sampling points adjacent to the first inflection point, wherein P is an integer greater than or equal to 1; and

determining, as the second data segment, a second set of the second inflection point and P second sampling points adjacent to the second inflection point.

4 . The echo signal processing method of claim 2 , further comprising:

dividing the first echo signal into M first data segments to obtain a first data segment set, wherein the first data segment is one of first Z data segments in the first data segment set, wherein the M first data segments are in a descending order based on first amplitude values of the M first data segments, and wherein M and Z are both integers greater than or equal to 1; and

dividing the second echo signal into M second data segments to obtain a second data segment set, wherein the second data segment is one of second Z data segments in the second data segment set, and wherein the M second data segments are in the descending order based on second amplitude values of the M second data segments.

5 . The echo signal processing method of claim 1 , comprising:

determining, from the first echo signal, a first inflection point set comprising first inflection points of the first echo signal, wherein the first inflection point is any one of first N inflection points in the first inflection point set, and wherein the first inflection points are in a descending order based on corresponding amplitude values of the first inflection points; and

determining, from the second echo signal, a second inflection point set comprising second inflection points of the second echo signal, wherein the second inflection point is any one of first N inflection points in the second inflection point set, and wherein the second inflection points are in the descending order based on corresponding amplitude values of the second inflection points.

6 . The echo signal processing method of claim 1 , further comprising associating, in response to the first determination, the first echo signal and the second echo signal with a same target object.

7 . The echo signal processing method of claim 1 , further comprising controlling a microelectromechanical system (MEMS) micromirror to scan the FOV.

8 . The echo signal processing method of claim 1 , further comprising:

determining a third sampling point having a largest amplitude value from the combined signal;

determining a third moment corresponding to the third sampling point; and

calculating, based on the third moment, a distance between the target object and a receive point that receives the first echo signal.

9 . The echo signal processing method of claim 6 , wherein before determining that the first direction and the second direction are located in the target area, the echo signal processing method further comprises determining the first direction and a neighboring area of the first direction as the target area.

10 . The echo signal processing method of claim 1 , wherein a first signal-to-noise ratio of the first echo signal is less than a second preset threshold, and wherein a second signal-to-noise ratio of the second echo signal is less than a third preset threshold.

11 . The echo signal processing method of claim 1 , wherein the noise reduction processing further comprises Gaussian filtering.

12 . A light detection and ranging (LiDAR) system, comprising:

a processor; and

a non-transitory storage medium coupled to the processor and configured to store program instructions, wherein, when executed by the processor, the program instructions cause the apparatus to:

receive, in different directions, echo signals comprising a first echo signal and a second echo signal;

determine a first inflection point from the first echo signal, wherein the first inflection point is a first sampling point of the first echo signal, and wherein first amplitude values of a first left neighboring sampling point of the first inflection point and a first right neighboring sampling point of the first inflection point are less than a second amplitude value of the first inflection point;

determine a second inflection point from the second echo signal, wherein the second inflection point is a second sampling point of the second echo signal, and wherein third amplitude values of a second left neighboring sampling point of the second inflection point and a second right neighboring sampling point of the second inflection point are less than a fourth amplitude value of the second inflection point;

divide, by a processor of the LiDAR system, a field of view (FOV) corresponding to receiving at least one echo signal into a plurality of target areas, wherein the FOV comprises a target object;

make a first determination that a first direction that the first echo signal is received and a second direction that the second echo signal is received are located in a same target area among the plurality of target areas;

separately perform, in response to the first determination, noise reduction processing on the first echo signal and the second echo signal, wherein the noise reduction processing comprises at least one of matched filtering, wavelet-domain denoising, or frequency-domain filtering;

make, in response to the first determination, a second determination that a time difference between a first moment when the first inflection point is received from the first echo signal and a second moment when the second inflection point is received from the second echo signal is less than or equal to a first preset threshold; and

combine, in response to the second determination, the first echo signal and the second echo signal to obtain a combined signal.

13 . The LiDAR system of claim 12 , wherein the program instructions further cause the LiDAR system to:

determine a first data segment from the first echo signal, wherein the first inflection point is in the first data segment;

determine a second data segment from the second echo signal, wherein the second inflection point is in the second data segment; and

combine the first data segment and the second data segment.

14 . The LiDAR system of claim 12 , wherein the program instructions further cause the LiDAR system to associate, in response to the first determination, the first echo signal and the second echo signal with a same target object.

15 . The LiDAR system of claim 14 , wherein the program instructions further cause the LiDAR system to determine the first direction and a neighboring area of the first direction as the target area.

16 . The LiDAR system of claim 14 , wherein the program instructions further cause the LiDAR system to control a microelectromechanical systems (MEMS) micromirror to scan the FOV.

17 . The LiDAR system of claim 16 , wherein the program instructions further cause the LiDAR system to:

determine a third sampling point having a largest amplitude value from the combined signal;

determine a third moment corresponding to the third sampling point; and

determine, based on the third moment, a distance between the target object and a receive point that receives the first echo signal.

18 . The LiDAR system of claim 12 , wherein a first signal-to-noise ratio of the first echo signal is less than a second preset threshold, and wherein a second signal-to-noise ratio of the second echo signal is less than a third preset threshold.

19 . The LiDAR system of claim 12 , wherein the noise reduction processing further comprises Gaussian filtering.

20 . A computer program product comprising computer-executable instructions stored on a non-transitory computer readable medium that, when executed by a processor, cause a light detection and ranging (LiDAR) system to:

receive, in different directions, echo signals comprising a first echo signal and a second echo signal;

determine a first inflection point from the first echo signal, wherein the first inflection point is a first sampling point of the first echo signal, and wherein first amplitude values of a first left neighboring sampling point of the first inflection point and a first right neighboring sampling point of the first inflection point are less than a second amplitude value of the first inflection point;

determine a second inflection point from the second echo signal, wherein the second inflection point is a second sampling point of the second echo signal, and wherein third amplitude values of a second left neighboring sampling point of the second inflection point and a second right neighboring sampling point of the second inflection point are less than a fourth amplitude value of the second inflection point;

divide, by a processor of the LiDAR system, a field of view (FOV) corresponding to receiving at least one echo signal into a plurality of target areas, wherein the FOV comprises a target object;

make a first determination that a first direction that the first echo signal is received and a second direction that the second echo signal is received are located in a same target area among the plurality of target areas;

separately perform, in response to the first determination, noise reduction processing on the first echo signal and the second echo signal, wherein the noise reduction processing comprises at least one of matched filtering, wavelet-domain denoising, or frequency-domain filtering;

make, in response to the first determination, a second determination that a time difference between a first moment when the first inflection point is received from the first echo signal and a second moment when the second inflection point is received from the second echo signal is less than or equal to a preset threshold; and

combine, in response to the second determination, the first echo signal and the second echo signal to obtain a combined signal.