CN115575965A - Laser radar multi-echo discrimination method and device - Google Patents
Laser radar multi-echo discrimination method and device Download PDFInfo
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- CN115575965A CN115575965A CN202211098105.6A CN202211098105A CN115575965A CN 115575965 A CN115575965 A CN 115575965A CN 202211098105 A CN202211098105 A CN 202211098105A CN 115575965 A CN115575965 A CN 115575965A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
Abstract
The invention relates to a laser radar multi-echo discrimination method and a device, comprising the following steps: obtaining T i And T i+1 Image I taken by a time camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; from lidar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses; calculating the projection to I according to the position coordinate P of the target point by using a camera imaging model i Upper image coordinate M i And its projection onto I i+1 Upper image coordinate M i+1 (ii) a Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i‑1 And matching the laser radar emission pulse at the moment. The invention can effectively solve the problem of laser radar pulse in the laser radar ranging processThe returned signal and the transmitted pulse signal can not correspond to each other, so that the problem of range ambiguity is caused.
Description
Technical Field
The invention relates to the technical field of radar ranging, in particular to a laser radar multi-echo discrimination method and device.
Background
The lidar system performs ranging measurements based on the principle of laser pulse time of flight. The prerequisite that each received echo pulse needs to be correlated with its induced emission laser pulse during ranging results in LiDAR (LiDAR) ranging with Ranging (RG) limitations, i.e., pulse emission and reception times less than the pulse repetition frequency (PRR) are required to accurately determine the distance of the pulse emission location to the target. Ranging ambiguities can arise if the round-trip time of a pulse exceeds the pulse transmission repetition frequency, i.e. the returned signal and the previous pulse signal do not correspond, which limits the usability of high measurement rate rangefinders and lidar.
In actual production engineering, the ranging ambiguity problem is generally avoided by controlling the flying height of the unmanned aerial vehicle and adjusting the laser pulse emission frequency. If range ambiguity occurs in the point cloud, points significantly above or below the ground are also typically considered noise for removal. The method brings information loss of laser point cloud data, greatly reduces the utilization rate of the laser point cloud data, limits the sampling capacity of airborne LiDAR, and increases the number and times of flight zones of the airplane when the same high-density point cloud and a wider scanning zone are required to be reached.
The current ways to avoid the laser radar ranging ambiguity problem can be mainly divided into three types: hardware solutions, software solutions, and combinations of software and hardware. Hardware-based solutions are mainly space multiplexing and wavelength multiplexing. Spatial multiplexing is mainly achieved by superposing at least two similar laser emitting and receiving devices on a complete laser scanning system platform. This solution requires the simultaneous operation of two laser scanning devices while maintaining a maximum clear distance for each single device and requires a spatial separation of the fields of view (FOV) of the two instruments large enough to avoid interference with each other. Wavelength multiplexing is primarily the operation of two or more laser scanners at different wavelengths to avoid problems caused by interference. Due to the technical complexity required to develop a single instrument capable of transmitting and receiving laser pulses at multiple wavelengths, and the lack of flexibility in selecting different wavelengths during operation, the currently applied approach is to choose separate instruments for two or more specific wavelengths.
Hardware-based solutions do not completely solve the problem of fuzzy measurement, and software-based approaches can overcome this problem. Software-based methods are mainly based on the use of assumptions about the continuity of the surface of the measurement object and variable period measurement techniques. The method finds out adjacent laser points through neighborhood division, then calculates the statistical weight of the adjacent points in different pulse transceiving periods to obtain a real pulse transceiving interval, and further corrects the laser points. In order to correctly correlate all the successive measurements, a correct initial transceiving cycle region needs to be selected. Software algorithm approaches often result in poor solution versatility because neither business barriers disclose specific details to resolve ranging ambiguities, or can only be used in a single vendor's data.
Disclosure of Invention
The invention provides a laser radar multi-echo discrimination method and device, and aims to solve the problem of range finding ambiguity caused by the fact that a return signal of a laser radar pulse and a transmitted pulse signal cannot correspond to each other in the laser radar range finding process.
The technical scheme for solving the technical problems is as follows:
in a first aspect, the present invention provides a laser radar multi-echo determination method, including:
obtaining T i And T i+1 Image I taken by a time camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
from laser radar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
calculating the projection to I according to the position coordinate P of the target point by using a camera imaging model i Upper image coordinate M i And its projection onto I i+1 Upper image coordinate M i+1 ；
Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
Further, when the number of cycles for acquiring the laser radar echo pulse is greater than one cycle, the matched laser radar echo pulse is deleted from the laser radar echo pulse acquired in the next iteration process.
Further, the upper limit of the cycle number of the obtained laser radar echo pulse is determined according to hardware parameters of a laser radar system.
Further, the image coordinate M is calculated i And image coordinates M i+1 The similarity of (2) includes:
in picture I i Up-capture image coordinates M i In image I i+1 Up-taking image coordinates M i+1 The neighborhood of pixels of (a);
according to image coordinates M i Calculates its corresponding local texture feature F i (ii) a According to the figureImage coordinate M i+1 Calculates the corresponding local texture feature F of the neighborhood pixel i+1 ；
Measuring local texture features F using correlation coefficients i And F i+1 The similarity of (c).
In a second aspect, the present invention provides a lidar multi-echo determination apparatus, including:
data acquisition module, acquire T i And T i+1 Image I taken by a moment camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
coordinate calculation module based on laser radar echo pulse and T i The laser radar transmitting pulse at the moment resolves the position coordinate P of a target point corresponding to the echo pulse;
a projection calculation module for calculating the position coordinate P of the target point according to the camera imaging model i Image coordinate M of i And its projection onto I i+1 Image coordinate M of i+1 ；
A matching module for calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
Further, when the cycle number of the acquired laser radar echo pulses is larger than one cycle, the matched laser radar echo pulses are deleted from the laser radar echo pulses acquired in the next iteration process.
Further, the upper limit of the cycle number of the obtained laser radar echo pulse is determined according to hardware parameters of a laser radar system.
Further, the matching module includes: a similarity calculation module, the similarity module specifically configured to:
in picture I i Up-capture image coordinates M i In image I i+1 Up-capture image coordinates M i+1 A neighborhood of pixels;
according to image coordinates M i Calculates its corresponding local texture feature F i (ii) a According to image coordinates M i+1 Calculates its corresponding local texture feature F i+1 ；
Measuring local texture features F using correlation coefficients i And F i+1 The similarity of (c).
In a third aspect, the present invention provides an electronic device comprising:
a memory for storing a computer software program;
and the processor is used for reading and executing the computer software program so as to realize the multi-echo discrimination method for the laser radar in the first aspect of the invention.
In a fourth aspect, the present invention provides a non-transitory computer-readable storage medium, in which a computer software program for implementing the laser radar multiple echo determination method according to the first aspect of the present invention is stored.
The invention has the beneficial effects that: the invention can effectively solve the corresponding relation between the laser radar pulse return signal and the transmitting signal by means of the camera module, and solves the problem of range finding ambiguity.
The method can solve the problem of radar pulse ranging ambiguity only by carrying a camera on the basis of a LiDAR system, and has high economy and wider application range; the camera system does not need to be calibrated with the LiDAR system, only the camera is calibrated, and the system is simple and high in stability.
Drawings
FIG. 1 is an example of a waveform of a transmit pulse and a receive echo without ambiguity;
FIG. 2 is an example of an ambiguous transmit pulse and receive echo waveform;
fig. 3 is a schematic flow chart of a method for determining multiple echoes of a laser radar according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of the pulse transmission and echo transmission and reception time in the embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a laser pulse disambiguation principle according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a multi-echo discrimination apparatus for laser radar according to an embodiment of the present invention;
fig. 7 is a schematic diagram of an embodiment of an electronic device according to an embodiment of the present invention;
fig. 8 is a schematic diagram of an embodiment of a computer-readable storage medium according to an embodiment of the present invention.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
The laser radar can obtain a series of measuring point distances according to light flight parameters by periodically emitting laser and receiving echo waves, and the position of a reflecting point can be calculated by combining the position and the attitude of the laser. In general, the laser is transmitted and received in sequence, i.e. transmission-reception-transmission-reception, there is always only one laser pulse in the air, and reception and transmission are matched one by one. If an object is measured far away, a plurality of pulses may appear in the air, the sequence of the plurality of pulses arriving at the receiver is no longer consistent with the sequence of pulse transmission, the receiver cannot correctly calculate the flight Time of the pulses, and therefore the distance measurement of the object cannot be correctly obtained, namely, the MTA (Multi-Time-Around) problem, and the number of receiving and transmitting cycles that a reflected signal may cross is generally called as the MTA interval. Fig. 1 shows that the transmitted pulse and the received echo are matched one by one, and there is no range interval with range ambiguity and range ambiguity, and fig. 2 shows that the transmitted pulse and the received echo do not correspond to each other any more and there is a range interval with range ambiguity.
The embodiment of the invention provides a laser radar multi-echo judging method, which is characterized in that image information of a laser radar echo time is obtained through camera equipment synchronized by a LiDAR system, the corresponding relation between the laser radar echo time and a laser pulse emission time is unknown, but within a specified period, an assumed ranging value of each echo is recorded by assuming that each echo corresponds to an emission pulse, and the image information of the assumed ranging value is inevitably stored in the image information synchronously obtained at the emission pulse time. When the carrier moves for a certain distance, the camera also acquires an image at another position, and the corresponding relation between the laser echo and the emission pulse is determined by comparing the similarity of two points of the two images.
Specifically, as shown in fig. 3, a method for determining multiple echoes of a laser radar according to an embodiment of the present invention includes the following steps:
obtaining T i And T i+1 Image I taken by a moment camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
from laser radar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
calculating the projection to I according to the position coordinate P of the target point by using a camera imaging model i Image coordinate M of i And its projection to I i+1 Upper image coordinate M i+1 ；
Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with the T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
The modern laser radar System is provided with a GPS, an IMU and the like to obtain POS data, if the Position and direction information contained in the POS (Position and Orientation System) data of each laser pulse can be utilized to reconstruct a three-dimensional space scene during laser transmission, a transmitted laser pulse mathematical model can be established in the specified direction and speed, a laser echo object is projected into an image by combining with a camera imaging model, and the similarity between the images at the echo positions is calculated in the images shot by cameras at different positions so as to determine the corresponding relation between the echo pulse and the transmitted pulse, thereby solving the problem of range finding ambiguity.
Suppose T 1 At any moment, the laser radar emits laser pulses, and simultaneously triggers the camera to take a picture to obtain an image I 1 The laser pulse generates three echoes when meeting objects at different levels on the ground, and the time of receiving the echoes is t in sequence 11 ，t 12 ，t 13 . After a pulse interval Δ T, T 2 The laser radar emits laser pulses at any time, and the camera acquires an image I 2 The laser pulse also generates three echoes after meeting objects at different levels on the ground, and the time of receiving the echoes is t in sequence 21 ，t 22 ，t 23 . After a pulse interval Δ T, the lidar emits a pulse T 3 Obtaining images as I simultaneously 3 . The lidar time instants are shown in fig. 4.
The LiDAR system can solve the distance from the pulse reflection to the radar by the time difference between the laser pulse return time and the laser pulse transmission time. At T as shown in FIG. 4 2 Time to T 3 There are three radar returns in the time radar pulse period, wherein the return t 13 The corresponding radar transmitting pulse time is T 1 . First assume at T 2 Echo t received in a cycle 13 ，t 21 ，t 22 Are all consistent with the transmission pulse T 2 Correspondingly, the echo t is solved by the radar system 13 ，t 21 ，t 22 Corresponding reflection object position P 13 (x 13 ,y 13 ,z 13 )，P 21 (x 21 ,y 21 ,z 21 )，P 22 (x 22 ,y 22 ,z 22 ) As shown in fig. 5.
According to the camera imaging model:
s·M＝A[R|t]P
wherein s is a proportionality constant, P represents the coordinates of a space point, M represents the coordinates of a pixel point projected on an image plane, A represents a camera internal reference matrix, and [ R | t ] represents a camera rotation and translation matrix.
Laser pulse return position coordinate P 13 (x 13 ,y 13 ,z 13 )，P 21 (x 21 ,y 21 ,z 21 )，P 22 (x 22 ,y 22 ,z 22 ) Can be projected on to the image I 2 Image coordinates
When the camera moves to the next time such as T along with the carrier 3 According to T 2 Position coordinate P calculated by time echo 13 (x 13 ,y 13 ,z 13 )，P 21 (x 21 ,y 21 ,z 21 )，P 22 (x 22 ,y 22 ,z 22 ) Conversion to image I by Camera imaging model 3 Image coordinates
According to image I 2 Coordinates of the image of
And image I 3 Coordinates of the object
The neighborhood pixels of (a) compute local texture LBP features, which are computed by pearson's correlation coefficient metric for two corresponding image coordinates (e.g.,
and with
And
and
) And (3) the similarity degree of the characteristics of the neighborhood LBP is high, and the laser echo at the position P is considered to be analyzed correctly if the similarity degree is high. It should be understood that in addition to utilizing the LBP feature in this schemeBesides the similarity of the two image coordinates is measured by the pearson correlation coefficient, other common image similarity judgment methods can be adopted, such as cosine distance, histogram, euclidean distance and the like.
If the degree of similarity is low, e.g. coordinate P 13 (x 13 ,y 13 ,z 13 ) In I 2 And I 3 Corresponding point on the image
And
due to P 13 (x 13 ,y 13 ,z 13 ) The laser pulse actually matched with the corresponding echo pulse is T 1 At T 2 The position obtained by analysis in the corresponding laser pulse period is a virtual position, and in the process of projecting to the camera image plane, the actual imaging is through the object point corresponding to the virtual point. And the image characteristics of all the ambiguous analysis positions of the laser pulse echoes projected to different image planes at different moments have larger difference, so that the laser pulse echoes correspond to the emitted laser pulses, and the accurate ranging analysis of each echo is realized.
As shown in fig. 6, an embodiment of the present invention further provides a laser radar multi-echo determination device, including:
a data acquisition module for acquiring T i And T i+1 Image I taken by a moment camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
coordinate calculation module based on laser radar echo pulse and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
a projection calculation module for calculating the projection of the target point to the target point I according to the position coordinate P of the target point by using the camera imaging model i Images ofCoordinate M i And its projection onto I i+1 Upper image coordinate M i+1 ；
A matching module for calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with the T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
The matching module comprises: a similarity calculation module, the similarity module specifically configured to:
in picture I i Up-capture image coordinates M i In image I i+1 Up-capture image coordinates M i+1 The neighborhood of pixels of (a);
according to image coordinates M i The neighborhood pixels calculate the corresponding local texture LBP characteristics F i (ii) a According to image coordinates M i+1 The neighborhood pixels calculate the corresponding local texture LBP characteristics F i+1 ；
Local texture LBP feature F measured by Pearson correlation coefficient i And F i+1 The similarity of (c).
Referring to fig. 7, fig. 7 is a schematic diagram of an embodiment of an electronic device according to an embodiment of the invention. As shown in fig. 7, an embodiment of the present invention provides an electronic device 500, which includes a memory 510, a processor 520, and a computer program 511 stored in the memory 520 and capable of running on the processor 520, where the processor 520 executes the computer program 511 to implement the following steps:
obtaining T i And T i+1 Image I taken by a moment camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar emits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
from lidar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
calculating the projection of the target point to I according to the position coordinate P of the target point by using a camera imaging model i Image coordinate M of i And its projection to I i+1 Upper image coordinate M i+1 ；
Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
Referring to fig. 8, fig. 8 is a schematic diagram illustrating an embodiment of a computer-readable storage medium according to the present invention. As shown in fig. 8, the present embodiment provides a computer-readable storage medium 600 on which a computer program 611 is stored, the computer program 611 implementing the following steps when executed by a processor:
obtaining T i And T i+1 Image I taken by a time camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is a unit of 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
from laser radar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
calculating the projection of the target point to I according to the position coordinate P of the target point by using a camera imaging model i Upper image coordinate M i And its projection to I i+1 Image coordinate M of i+1 ；
Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with the T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
It should be noted that, in the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to relevant descriptions of other embodiments for parts that are not described in detail in a certain embodiment.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A laser radar multi-echo discrimination method is characterized by comprising the following steps:
obtaining T i And T i+1 Image I taken by a moment camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is 1 The laser radar emits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
from laser radar echo pulses and T i The laser radar at the moment transmits pulses to resolve the position coordinates P of a target point corresponding to the echo pulses;
calculating the projection of the target point to I according to the position coordinate P of the target point by using a camera imaging model i Image coordinate M of i And its projection to I i+1 Upper image coordinate M i+1 ；
Calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
2. The method of claim 1, wherein the matched laser radar echo pulse is deleted from the laser radar echo pulses acquired in the next iteration process when the number of cycles for acquiring the laser radar echo pulse is greater than one cycle.
3. The method of claim 2, wherein an upper limit of the number of cycles to acquire the lidar return pulse is determined based on lidar system hardware parameters.
4. The method of claim 1, wherein said calculating image coordinates M i And image coordinates M i+1 The similarity of (2) includes:
in picture I i Up-capture image coordinates M i In image I i+1 Up-capture image coordinates M i+1 A neighborhood of pixels;
according to image coordinates M i Calculates its corresponding local texture feature F i (ii) a According to image coordinates M i+1 Calculates its corresponding local texture feature F i+1 ；
Measuring local texture features F using correlation coefficients i And F i+1 The similarity of (c).
5. A laser radar multi-echo discrimination device is characterized by comprising:
data acquisition module, acquire T i And T i+1 Image I taken by a time camera i And I i+1 And obtaining T i Receiving laser radar echo pulses in at least one period after the moment; wherein i is a positive integer; t is a unit of 1 The laser radar transmits pulses for the first time at any moment; the period is the pulse emission period of the laser radar;
coordinate calculation module based on laser radar echo pulse and T i The laser radar transmitting pulse at the moment resolves the position coordinate P of a target point corresponding to the echo pulse;
a projection calculation module for calculating the position coordinate P of the target point according to the camera imaging model i Image coordinate M of i And its projection to I i+1 Upper image coordinate M i+1 ；
A matching module for calculating image coordinates M i And image coordinates M i+1 If the similarity is higher than a preset threshold value, the radar echo corresponding to the target point is compared with the T i The laser radar emission pulse at the moment is matched, otherwise, the radar echo corresponding to the target point is matched with T i-1 And matching the laser radar emission pulse at the moment.
6. The apparatus of claim 5, wherein the matched laser radar echo pulse is deleted from the laser radar echo pulses obtained in the next iteration process when the number of cycles for obtaining the laser radar echo pulse is greater than one cycle.
7. The apparatus of claim 6, wherein an upper limit of the number of cycles to acquire the lidar return pulse is determined based on lidar system hardware parameters.
8. The apparatus of claim 5, wherein the matching module comprises: a similarity calculation module, the similarity module specifically configured to:
in picture I i Up-taking image coordinates M i In image I i+1 Up-taking image coordinates M i+1 A neighborhood of pixels;
according to image coordinates M i Calculates the corresponding local texture feature F of the neighborhood pixel i (ii) a According to image coordinates M i+1 Calculates its corresponding local texture feature F i+1 ；
Measuring local texture features F using correlation coefficients i And F i+1 The similarity of (c).
9. An electronic device, comprising:
a memory for storing a computer software program;
a processor for reading and executing the computer software program to realize a lidar multi-echo determination method according to any one of claims 1 to 4.
10. A non-transitory computer readable storage medium, wherein the storage medium stores a computer software program for implementing a lidar multi-echo discrimination method according to any one of claims 1 to 4.
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| CN117233734A (en) * | 2023-11-14 | 2023-12-15 | 山东富锐光学科技有限公司 | Laser radar data acquisition method and system based on TDC and ADC and laser radar |
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| CN117233734A (en) * | 2023-11-14 | 2023-12-15 | 山东富锐光学科技有限公司 | Laser radar data acquisition method and system based on TDC and ADC and laser radar |
| CN117233734B (en) * | 2023-11-14 | 2024-01-30 | 山东富锐光学科技有限公司 | Laser radar data acquisition method and system based on TDC and ADC and laser radar |
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