CN116068503A - Combined calibration method and device for millimeter wave radar and laser radar and terminal equipment - Google Patents
Combined calibration method and device for millimeter wave radar and laser radar and terminal equipment Download PDFInfo
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- CN116068503A CN116068503A CN202111275956.9A CN202111275956A CN116068503A CN 116068503 A CN116068503 A CN 116068503A CN 202111275956 A CN202111275956 A CN 202111275956A CN 116068503 A CN116068503 A CN 116068503A
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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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
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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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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Abstract
The application is suitable for the technical field of automatic driving, and provides a joint calibration method, device and terminal equipment of millimeter wave radar and laser radar. The combined calibration method comprises the following steps: acquiring an intermediate frequency signal received by a millimeter wave radar and a plurality of first echo signals received by a laser radar; determining position information of the corner reflector in a millimeter wave radar coordinate system according to the intermediate frequency signal; determining the distance between the corner reflector and the laser radar according to the first echo signals, wherein the distance between the corner reflector and the laser radar and the angle of the corner reflector in the view angle of the laser radar are the position information of the corner reflector in a laser radar coordinate system; and determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively. Through the method and the device, the spatial synchronization of the millimeter wave radar and the laser radar can be realized.
Description
Technical Field
The application belongs to the technical field of automatic driving, and particularly relates to a joint calibration method, device and terminal equipment of millimeter wave radar and laser radar.
Background
In the field of automatic driving, millimeter wave radars and laser radars have important roles as distance sensors, and can detect targets such as vehicles and pedestrians on roads and give information such as positions and speeds of the targets in a radar self coordinate system. Compared with a single radar, the millimeter wave radar and the laser radar are fused, and a better perception result can be obtained. However, before the millimeter wave radar and the laser radar are fused, spatial synchronization of the millimeter wave radar and the laser radar needs to be achieved.
Disclosure of Invention
The embodiment of the application provides a joint calibration method and device of millimeter wave radar and laser radar and terminal equipment, so as to realize space synchronization of the millimeter wave radar and the laser radar.
In a first aspect, an embodiment of the present application provides a method for jointly calibrating a millimeter wave radar and a laser radar, where a corner reflector is disposed in a sensing range of the millimeter wave radar and the laser radar, and the method includes:
acquiring an intermediate frequency signal received by the millimeter wave radar and a plurality of first echo signals received by the laser radar;
determining the position information of the corner reflector in a millimeter wave radar coordinate system according to the intermediate frequency signal;
Determining the distance between the corner reflector and the laser radar according to the first echo signals, wherein the distance between the corner reflector and the laser radar and the angle of the corner reflector in the view angle of the laser radar are the position information of the corner reflector in a laser radar coordinate system;
and determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively.
In a second aspect, an embodiment of the present application provides a joint calibration device for millimeter wave radar and laser radar, where a corner reflector is disposed in a sensing range of the millimeter wave radar and the laser radar, the joint calibration device includes:
the signal acquisition module is used for acquiring the intermediate frequency signals received by the millimeter wave radar and a plurality of first echo signals received by the laser radar;
the position determining module is used for determining the position information of the corner reflector in a millimeter wave radar coordinate system according to the intermediate frequency signal;
a distance determining module, configured to determine, according to the plurality of first echo signals, a distance between the corner reflector and the lidar, where the distance between the corner reflector and the lidar and an angle of the corner reflector in a view angle of the lidar are location information of the corner reflector in a lidar coordinate system;
And the pose determining module is used for determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively.
In a third aspect, an embodiment of the present application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the steps of the joint calibration method according to the first aspect.
In a fourth aspect, embodiments of the present application provide a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the joint calibration method according to the first aspect.
In a fifth aspect, embodiments of the present application provide a computer program product which, when run on a terminal device, causes the terminal device to perform the steps of the joint calibration method according to the first aspect described above.
From the above, according to the method, the corner reflectors are arranged in the sensing ranges of the millimeter wave radar and the laser radar, intermediate frequency signals received by the millimeter wave radar and a plurality of first echo signals received by the laser radar can be obtained, the position information of the corner reflectors in the millimeter wave radar coordinate system is determined according to the intermediate frequency signals, the distance between the corner reflectors and the laser radar is determined according to the plurality of first echo signals, the distance between the corner reflectors and the laser radar and the angle of the corner reflectors in the view angle of the laser radar are the position information of the corner reflectors in the laser coordinate system, and the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system can be determined according to the position information of the corner reflectors in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system, so that the spatial synchronization of the millimeter wave radar and the laser radar is realized. According to the method, the corner reflectors placed in the sensing range of the millimeter wave radar and the laser radar are identified from the signal level, intermediate frequency signals and first echo signals returned by the corner reflectors can be identified in the stationary target, and the limitation that the millimeter wave Lei Dadian cloud only comprises the moving target is relieved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic implementation flow chart of a combined calibration method of millimeter wave radar and laser radar according to an embodiment of the present application;
fig. 2 is an exemplary view of a corner reflector;
FIG. 3 is an exemplary plot of echo intensities of two first echo signals;
fig. 4 is a schematic implementation flow chart of a combined calibration method of millimeter wave radar and laser radar according to a second embodiment of the present application;
fig. 5 is a schematic structural diagram of a joint calibration device of millimeter wave radar and laser radar according to a third embodiment of the present application;
fig. 6 is a schematic structural diagram of a terminal device according to a fourth embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
In addition, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and are not to be construed as indicating or implying relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
When the spatial synchronization of the millimeter wave radar and the laser radar (for example, the spatial synchronization of the vehicle-mounted millimeter wave radar and the vehicle-mounted laser radar or the spatial synchronization of the road-end millimeter wave radar and the road-end laser radar) is realized, the existing scheme is a method based on manual physical measurement, and the method needs manual participation, and is low in efficiency and poor in precision. In order to solve the technical problems existing in the prior art, the embodiment of the application provides a joint calibration method of a millimeter wave radar and a laser radar, by setting a corner reflector in the sensing range of the millimeter wave radar and the laser radar, an intermediate frequency signal received by the millimeter wave radar and a plurality of first echo signals received by the laser radar can be obtained, the position information of the corner reflector in a millimeter wave radar coordinate system is determined according to the intermediate frequency signal, the distance between the corner reflector and the laser radar is determined according to the plurality of first echo signals, the distance between the corner reflector and the laser radar and the angle of the corner reflector in the view angle of the laser radar are the position information of the corner reflector in the laser coordinate system, and the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system can be determined according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system, so that the space synchronization of the millimeter wave radar and the laser radar is realized, manual participation is not needed, and the space synchronization efficiency and precision of the millimeter wave radar and the laser radar are improved.
It should be understood that the sequence number of each step in this embodiment does not mean the sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.
In order to illustrate the technical solutions described in the present application, the following description is made by specific examples.
Referring to fig. 1, a schematic implementation flow diagram of a combined calibration method of millimeter wave radar and laser radar according to an embodiment of the present application is provided, where the combined calibration method is applied to a terminal device. As shown in fig. 1, the joint calibration method may include the following steps:
In an embodiment, a corner reflector may be disposed in a sensing range of the millimeter wave radar and the laser radar, so as to realize joint calibration of the millimeter wave radar and the laser radar based on the corner reflector.
It should be noted that, the premise of realizing the joint calibration of the millimeter wave radar and the laser radar is that the millimeter wave radar and the laser radar are relatively static so as to ensure that the joint calibration of the millimeter wave radar and the laser radar can be realized.
The corner reflector is a radar wave reflector with different specifications, which is made of metal plates according to different purposes. When the radar electromagnetic wave scans the corner reflector, the electromagnetic wave can generate refraction amplification on the metal angle to generate a strong echo signal, namely the corner reflector has extremely strong reflection echo characteristic. As shown in fig. 2, which is an example of a corner reflector, the corner reflector in fig. 2 is formed by splicing three right triangle metal plates, and can reflect electromagnetic waves emitted at more angles back to the signal emission direction.
In order to reduce the influence of other targets with stronger reflection echo characteristics on the joint calibration of the millimeter wave radar and the laser radar, the millimeter wave radar and the laser radar can be placed in a scene without stronger echo. For example, when the millimeter wave radar and the laser radar are a vehicle-mounted millimeter wave radar and a vehicle-mounted laser radar, the vehicle equipped with the millimeter wave radar and the laser radar can be driven into a space which is open and free of obvious metal reflectors. When the millimeter wave radar and the laser radar are the road-end millimeter wave radar and the road-end laser radar, the metal reflectors with stronger echoes are ensured to be absent in the perception range of the millimeter wave radar and the laser radar as much as possible.
The intermediate frequency signal received by the millimeter wave radar is a frequency difference signal obtained by the electromagnetic wave transmitted by the millimeter wave radar and the received echo signal reflected back through a mixer.
As an alternative embodiment, the terminal device may send signal acquisition instructions to the millimeter wave radar and the laser radar respectively at the same time, the millimeter wave radar feeds back the received intermediate frequency signal to the terminal device after receiving the signal acquisition instructions, and the laser radar feeds back the received multiple first echo signals to the terminal device after receiving the signal acquisition instructions.
As another alternative embodiment, the millimeter wave radar actively transmits the intermediate frequency signal to the terminal device when receiving the intermediate frequency signal, and the lidar actively transmits the plurality of first echo signals to the terminal device when receiving the plurality of first echo signals.
And 102, determining the position information of the corner reflector in the millimeter wave radar coordinate system according to the intermediate frequency signal.
The millimeter wave radar coordinate system may refer to a coordinate system established with the millimeter wave radar as an origin.
The position information of the corner reflector in the millimeter wave radar coordinate system includes a distance of the corner reflector from the millimeter wave radar and an angle of the corner reflector in a view angle of the millimeter wave radar.
Optionally, determining the position information of the corner reflector in the millimeter wave radar coordinate system according to the intermediate frequency signal includes:
performing distance Fourier transform on the intermediate frequency signal to obtain a first Fourier transform result;
according to the first Fourier transform result, determining the frequency of a second echo signal returned by the corner reflector, wherein the second echo signal is an echo received by the millimeter wave radar;
determining the distance between the corner reflector and the millimeter wave radar according to the frequency of the second echo signal returned by the corner reflector;
doppler Fourier transform is carried out on the intermediate frequency signal, and a second Fourier transform result is obtained;
determining Doppler frequency shift of the intermediate frequency signal according to the second Fourier transform result;
the angle of the corner reflector in the view angle of the millimeter wave radar is determined according to the Doppler shift of the intermediate frequency signal.
In the intermediate frequency signals received by the millimeter wave radar, the intermediate frequency signals with different frequencies can be obtained according to the distances between different targets and the millimeter wave radar in the perception range, so the distance between the corner reflector and the millimeter wave radar can be determined by carrying out distance Fourier transform on the intermediate frequency signals received by the millimeter wave radar and according to the extremely strong reflection echo characteristic of the corner reflector.
The calculation formula of the distance between the corner reflector and the millimeter wave radar is as follows:
wherein c represents the speed of light in vacuum, f represents the frequency of the first echo signal to which the corner reflector belongs, and s represents the frequency modulation slope of the frequency modulation signal emitted by the millimeter wave radar.
The calculation formula of the angle of the corner reflector in the view angle of the millimeter wave radar is as follows:
wherein d a The physical distance between two receiving antennas in the millimeter wave radar is represented, lambda represents the wavelength of the intermediate frequency signal, and omega represents the Doppler frequency shift of the intermediate frequency signal.
Alternatively, the fourier transform in the present application may refer to a fast fourier transform to increase the operation speed.
Optionally, determining the frequency of the second echo signal returned by the corner reflector according to the first fourier transform result includes:
searching the frequency of the peak from the first Fourier transform result, and determining the frequency of the peak as the frequency of a second echo signal returned by the corner reflector;
determining the Doppler shift of the intermediate frequency signal based on the second Fourier transform result comprises:
and searching the frequency shift of the peak from the second Fourier transform result, and determining the frequency shift of the peak as the Doppler frequency shift of the intermediate frequency signal.
Because the corner reflector has extremely strong reflection echo characteristics, the reflectivity of the corner reflector is far higher than other targets in the perception range, so that the frequency of the peak in the first Fourier transform result can be determined to be the frequency of a second echo signal returned by the corner reflector, and the frequency shift of the peak in the second Fourier transform result is the Doppler frequency shift of the intermediate frequency signal.
The laser radar coordinate system may refer to a coordinate system established by taking the laser radar as an origin.
Since the angle of the corner reflector in the view angle of the lidar is fixed at the time of emission, the angle of the corner reflector in the view angle of the lidar is a fixed value without calculation.
Optionally, determining the distance between the corner reflector and the lidar based on the plurality of first echo signals includes:
determining a first echo signal returned by the corner reflector from the plurality of first echo signals;
and determining the distance between the corner reflector and the laser radar according to the time difference between the laser radar transmitting signal and the first echo signal returned by the corner reflector.
The calculation formula of the distance between the corner reflector and the laser radar is as follows:
where Δt represents the time difference between the laser radar transmit signal and the first echo signal received back from the corner reflector.
Optionally, determining the first echo signal returned by the corner reflector from the plurality of first echo signals includes:
Acquiring the saturation degree of echo intensities of a plurality of first echo signals;
and determining the first echo signal with the largest saturation degree of the echo intensity as the first echo signal returned by the corner reflector.
Among the plurality of first echo signals received by the lidar, waveforms with different saturation degrees can be obtained by different echo intensities, and as shown in fig. 3, two exemplary diagrams of echo intensities of the first echo signals are shown, and the saturation degree of one first echo signal can be understood as the area of an area surrounded by the echo intensity curve of the first echo signal and the X-axis and the Y-axis. As can be seen from fig. 3, the saturation level of the first echo signal a is higher than the saturation level of the first echo signal B.
Because the reflectivity of the corner reflector is far higher than that of other targets in the perception range, the saturation degree of the first echo signals returned by the corner reflector is far higher than that of the other targets, and the first echo signal with the highest saturation degree in the plurality of first echo signals is the first echo signal returned by the corner reflector.
And 104, determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively.
In the embodiment, the corner reflector is used as a reference point, and the coordinate transformation relation between the millimeter wave radar and the laser radar can be calculated according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information of the corner reflector in the laser radar coordinate system, wherein the coordinate transformation relation is the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system.
According to the embodiment of the application, the corner reflectors are arranged in the sensing ranges of the millimeter wave radar and the laser radar, intermediate frequency signals received by the millimeter wave radar and a plurality of first echo signals received by the laser radar can be obtained, the position information of the corner reflectors in the millimeter wave radar coordinate system is determined according to the intermediate frequency signals, the distance between the corner reflectors and the laser radar is determined according to the plurality of first echo signals, the distance between the corner reflectors and the laser radar and the angle of the corner reflectors in the view angle of the laser radar are the position information of the corner reflectors in the laser coordinate system, and the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system can be determined according to the position information of the corner reflectors in the millimeter wave radar coordinate system and the position information of the corner reflectors in the laser radar coordinate system, so that the spatial synchronization of the millimeter wave radar and the laser radar is realized.
Referring to fig. 4, a schematic implementation flow diagram of a combined calibration method of millimeter wave radar and laser radar provided in a second embodiment of the present application is provided, where the combined calibration method is applied to a terminal device. As shown in fig. 4, the joint calibration method may include the steps of:
The step is the same as step 101, and specific reference may be made to the description related to step 101, which is not repeated here.
And step 402, determining the position information of the corner reflector in the millimeter wave radar coordinate system according to the intermediate frequency signal.
The step is the same as step 102, and the detailed description of step 102 is omitted here.
The step is the same as step 103, and specific reference may be made to the related description of step 103, which is not repeated here.
The first position information sets comprise position information of the corner reflectors in a millimeter wave radar coordinate system and position information of the corner reflectors in a laser radar coordinate system when the corner reflectors are at one position, the corner reflectors are sequentially arranged at N different positions, the N different positions correspond to the N first position information sets, and N is an integer larger than 1.
The positions of the millimeter wave radar and the laser radar are kept unchanged, the corner reflectors can be sequentially placed at N different positions, the steps 401 to 403 are repeatedly executed, and the first position information sets corresponding to the N different positions respectively can be obtained. The corner reflectors can be placed uniformly when being placed, namely, the distance interval between two adjacent placement times is a fixed value, so that the calculation accuracy of the subsequent relative pose is ensured.
For a first set of location information, the residual of the first set of location information may be represented as follows:
p LIDAR -(R·p RADAR +T)
wherein p is LIDAR Representing position information of corner reflector in laser radar coordinate system, p RADAR Representing position information of the corner reflector in the millimeter wave radar coordinate system, R and T represent first optimization parameters.
In step 405, the residuals of each of the N first location information groups are accumulated to obtain a first accumulated sum.
The first accumulated sum may be represented as follows:
e * ＝∑p LIDAR -(R·p RADAR +T)
and step 406, adjusting the first optimization parameters so that the first summation is minimum, wherein the optimization parameters when the first summation is minimum are the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system.
Wherein, let e * And the optimal parameters R and T when the minimum is reached are the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system.
Optionally, the present embodiment further includes:
acquiring absolute position information of the corner reflector;
converting the absolute position information of the corner reflector into an ENU coordinate system to obtain the position information of the corner reflector in the ENU coordinate system, wherein the ENU coordinate system is determined based on any position in the sensing range of the millimeter wave radar and the laser radar;
determining the pose of the millimeter wave radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the millimeter wave radar coordinate system;
determining the absolute pose of the millimeter wave radar according to the pose of the millimeter wave radar relative to an ENU coordinate system;
determining the pose of the laser radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the laser radar coordinate system;
And determining the absolute pose of the laser radar according to the pose of the laser radar sensor relative to the ENU coordinate system.
The absolute position information of the corner reflector refers to absolute coordinates of the corner reflector relative to the earth, and the absolute position information of the corner reflector can be represented by using universal transverse ink card trawl system (Universal Transverse Mercator Grid System, UTM) coordinates or longitude and latitude coordinates of the corner reflector.
In an embodiment, the absolute position information of the corner reflector may be measured by a Real-Time Kinematic (RTK) carrier phase difference device, and the RTK carrier phase difference device may send the measured absolute position information of the corner reflector to the terminal device, or the user may input the measured absolute position information of the corner reflector to the terminal device, which is not limited herein. The RTK carrier phase difference device is high-precision guide positioning equipment, and can measure longitude and latitude coordinates (Lon, lat), altitude h and the like of the corner reflector and record the measured data.
Taking longitude and latitude coordinates of the corner reflector as an example, the coordinate system of the ENU can be simplified based on the position information (Lon 0, lat 0) of any position in the sensing range as an origin, the east direction as the positive direction of the x axis, the north direction as the positive direction of the y axis, the sky direction as the positive direction of the z axis. Converting longitude and latitude coordinates of the measured corner reflector into an ENU coordinate system, wherein the conversion formula is as follows:
Wherein R is M 、R N The calculation formula of the curvature radius of the earth meridian circle and the mortise circle corresponding to the position of the corner reflector is as follows:
wherein R is e 、R p The radii of the long half shaft and the short half shaft of the earth are respectively, and e is the eccentricity of the spheroid of the revolution of the earth. The radius of the major and minor half axes of the earth adopts the parameters of the world's earth coordinate system (World Geodetic System-1984 Coordinate System,WGS-84) of 1984.
In an embodiment, one second position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the millimeter wave radar coordinate system respectively at one position, one third position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the laser radar coordinate system respectively at one position, the corner reflector is sequentially arranged at N different positions, the N different positions correspond to the N second position information groups and the N third position information groups, and N is an integer greater than 1; determining the pose of the millimeter wave radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the millimeter wave radar coordinate system respectively comprises:
calculating respective residual errors of the N second position information groups according to the N second position information groups and the second optimization parameters;
Accumulating the residual errors of each of the N second position information groups to obtain a second accumulated sum;
adjusting a second optimization parameter to enable a second accumulation sum to be minimum, wherein the second optimization parameter when the second accumulation sum is minimum is the pose of the millimeter wave radar relative to an ENU coordinate system;
determining the pose of the lidar relative to the ENU coordinate system based on the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the lidar coordinate system, respectively, includes:
calculating respective residual errors of the N third position information groups according to the N third position information groups and the third optimization parameters;
accumulating the residual errors of each of the N third position information groups to obtain a third accumulation sum;
and adjusting a third optimization parameter so that the third accumulation sum is minimum, wherein the third optimization parameter when the third accumulation sum is minimum is the pose of the laser radar relative to the ENU coordinate system.
For the second location information, the residual of the second location information may be represented as follows:
||p ENU -(R RADAR ·p RADAR +T RADAR )||
wherein p is ENU Representing position information of corner reflector in ENU coordinate system, R RADAR And T RADAR Representing a second optimization parameter.
The second accumulated sum may be represented as follows:
e RADAR ＝∑||p ENU -(R RADAR ·p RADAR +T RADAR )||
so that e RADAR Optimization function R when reaching minimum RADAR And T RADAR The pose of the millimeter wave radar relative to an ENU coordinate system is obtained.
For the third location information, the residual of the third location information may be represented as follows:
||p ENU -(R LIDAR ·p LIDAR +T LIDAR )||
wherein R is LIDAR And T LIDAR Representing a second optimization parameter.
The third accumulated sum may be represented as follows:
e LIDAR ＝∑||p ENU -(R LIDAR ·p LIDAR +T LIDAR )||
so that e LIDAR Optimization function R when reaching minimum LIDAR And T LIDAR The pose of the millimeter wave radar relative to an ENU coordinate system is obtained.
According to the method and the device, the corner reflector is controlled to move in the sensing range of the millimeter wave radar and the laser radar, so that the position information of the corner reflector in the millimeter wave radar coordinate system and the position information of the corner reflector in the laser radar coordinate system can be measured at different positions, residual optimization is carried out on the position information measured for multiple times, and the combined calibration accuracy of the millimeter wave radar and the laser radar can be improved.
Referring to fig. 5, a schematic structural diagram of a joint calibration device for millimeter wave radar and laser radar according to a third embodiment of the present application is provided, where a corner reflector is disposed in a sensing range of the millimeter wave radar and the laser radar. For convenience of explanation, only portions relevant to the embodiments of the present application are shown.
The combined calibration device comprises:
a signal acquisition module 51, configured to acquire an intermediate frequency signal received by the millimeter wave radar and a plurality of first echo signals received by the laser radar;
A position determining module 52, configured to determine, according to the intermediate frequency signal, position information of the corner reflector in a millimeter wave radar coordinate system;
a distance determining module 53, configured to determine, according to the plurality of first echo signals, a distance between the corner reflector and the lidar, where the distance between the corner reflector and the lidar and an angle of the corner reflector in a view angle of the lidar are location information of the corner reflector in a lidar coordinate system;
and a pose determining module 54, configured to determine a relative pose between the millimeter wave radar coordinate system and the lidar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the lidar coordinate system, respectively.
Optionally, the position information of the corner reflector in the millimeter wave radar coordinate system includes a distance between the corner reflector and the millimeter wave radar and an angle of the corner reflector in a viewing angle of the millimeter wave radar; the above-described position determination module 52 includes:
the first conversion unit is used for carrying out distance Fourier transform on the intermediate frequency signal to obtain a first Fourier transform result;
A first determining unit, configured to determine, according to the first fourier transform result, a frequency of a second echo signal returned by the corner reflector, where the second echo signal is an echo received by the millimeter wave radar;
a second determining unit configured to determine a distance between the corner reflector and the millimeter wave radar according to a frequency of a second echo signal returned by the corner reflector;
the second conversion unit is used for carrying out Doppler Fourier transform on the intermediate frequency signal to obtain a second Fourier transform result;
a third determining unit, configured to determine a doppler shift of the intermediate frequency signal according to the second fourier transform result;
and a fourth determining unit for determining an angle of the corner reflector in a view angle of the millimeter wave radar according to the Doppler shift of the intermediate frequency signal.
Optionally, the first determining unit is specifically configured to:
searching the frequency of the peak from the first Fourier transform result, and determining the frequency of the peak as the frequency of a second echo signal returned by the corner reflector;
the third determining unit is specifically configured to:
searching the frequency shift of the peak from the second Fourier transform result, and determining the frequency shift of the peak as the Doppler frequency shift of the intermediate frequency signal.
Optionally, the distance determining module 53 includes:
an echo determining unit configured to determine a first echo signal returned by the corner reflector from among the plurality of first echo signals;
and the distance determining unit is used for determining the distance between the corner reflector and the laser radar according to the time difference between the laser radar transmitting signal and the first echo signal returned by the corner reflector.
Optionally, the echo determination unit is specifically configured to:
acquiring the saturation degree of echo intensities of the plurality of first echo signals;
and determining the first echo signal with the largest saturation degree of the echo intensity as the first echo signal returned by the corner reflector.
Optionally, one first position information set includes position information of the corner reflector in the millimeter wave radar coordinate system and position information of the corner reflector in the laser radar coordinate system when in one position, the corner reflector is sequentially arranged at N different positions, the N different positions correspond to the N first position information sets, and N is an integer greater than 1; the pose determining module 54 specifically is configured to:
calculating respective residual errors of the N first position information groups according to the N first position information groups and the first optimization parameters;
Accumulating the residual errors of each of the N first position information groups to obtain a first accumulation sum;
and adjusting the first optimization parameters so that the first accumulation sum is minimum, wherein the optimization parameters when the first accumulation sum is minimum are the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system.
Optionally, the above combined calibration device further includes:
a position acquisition module for acquiring absolute position information of the corner reflector;
the position conversion module is used for converting the absolute position information of the corner reflector into an ENU coordinate system to obtain the position information of the corner reflector in the ENU coordinate system, and the ENU coordinate system is determined based on any position in the sensing range of the millimeter wave radar and the laser radar;
a first determining module, configured to determine a pose of the millimeter wave radar relative to the ENU coordinate system according to position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the millimeter wave radar coordinate system, respectively;
the second determining module is used for determining the absolute pose of the millimeter wave radar according to the pose of the millimeter wave radar relative to the ENU coordinate system;
A third determining module, configured to determine a pose of the lidar relative to the ENU coordinate system according to position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the lidar coordinate system, respectively;
and the fourth determining module is used for determining the absolute pose of the laser radar according to the pose of the laser radar sensor relative to the ENU coordinate system.
Optionally, one second position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the millimeter wave radar coordinate system when in one position, one third position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the laser radar coordinate system when in one position, the corner reflector is sequentially arranged at N different positions, N different positions correspond to N second position information groups and N third position information groups, N is an integer greater than 1; the first determining module is specifically configured to:
calculating respective residual errors of the N second position information groups according to the N second position information groups and the second optimization parameters;
accumulating the residual errors of each of the N second position information groups to obtain a second accumulated sum;
Adjusting the second optimization parameters so that the second accumulation sum is minimum, wherein the second optimization parameters when the second accumulation sum is minimum are the pose of the millimeter wave radar relative to the ENU coordinate system;
the third determining module is specifically configured to:
calculating respective residual errors of the N third position information groups according to the N third position information groups and third optimization parameters;
accumulating the residual errors of each of the N third position information groups to obtain a third accumulation sum;
and adjusting the third optimization parameters so that the third accumulation sum is minimum, wherein the third optimization parameters when the third accumulation sum is minimum are the pose of the laser radar relative to the ENU coordinate system.
The joint calibration device provided in the embodiment of the present application may be applied to the foregoing method embodiment, and details of the description of the foregoing method embodiment are referred to in the foregoing description, and are not repeated herein.
Fig. 6 is a schematic structural diagram of a terminal device according to a fourth embodiment of the present application. As shown in fig. 6, the terminal device 6 of this embodiment includes: one or more processors 60 (only one shown), a memory 61, and a computer program 62 stored in the memory 61 and executable on the at least one processor 60. The processor 60, when executing the computer program 62, implements the steps of the various joint calibration method embodiments described above.
The terminal device 6 may be a computing device such as a desktop computer, a notebook computer, a palm computer, a cloud server, etc. The terminal device may include, but is not limited to, a processor 60, a memory 61. It will be appreciated by those skilled in the art that fig. 6 is merely an example of the terminal device 6 and does not constitute a limitation of the terminal device 6, and may include more or less components than illustrated, or may combine certain components, or different components, e.g., the terminal device may further include an input-output device, a network access device, a bus, etc.
The processor 60 may be a central processing unit (Central Processing Unit, CPU), which may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 61 may be an internal storage unit of the terminal device 6, such as a hard disk or a memory of the terminal device 6. The memory 61 may be an external storage device of the terminal device 6, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the terminal device 6. Further, the memory 61 may also include both an internal storage unit and an external storage device of the terminal device 6. The memory 61 is used for storing the computer program and other programs and data required by the terminal device. The memory 61 may also be used for temporarily storing data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above device may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
The embodiments of the present application also provide a computer readable storage medium storing a computer program, where the computer program when executed by a processor implements steps of the foregoing method embodiments.
The embodiments of the present application also provide a computer program product, which when run on a terminal device, causes the terminal device to perform the steps that may implement the embodiments of the methods described above.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other manners. For example, the apparatus/terminal device embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical function division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each method embodiment described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (11)
1. The joint calibration method of the millimeter wave radar and the laser radar is characterized in that a corner reflector is arranged in the perception range of the millimeter wave radar and the laser radar, and the joint calibration method comprises the following steps:
acquiring an intermediate frequency signal received by the millimeter wave radar and a plurality of first echo signals received by the laser radar;
determining the position information of the corner reflector in a millimeter wave radar coordinate system according to the intermediate frequency signal;
determining the distance between the corner reflector and the laser radar according to the first echo signals, wherein the distance between the corner reflector and the laser radar and the angle of the corner reflector in the view angle of the laser radar are the position information of the corner reflector in a laser radar coordinate system;
And determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively.
2. The joint calibration method according to claim 1, wherein the positional information of the corner reflector in the millimeter wave radar coordinate system includes a distance of the corner reflector from the millimeter wave radar and an angle of the corner reflector in a view angle of the millimeter wave radar; the determining the position information of the corner reflector in the millimeter wave radar coordinate system according to the intermediate frequency signal comprises the following steps:
performing distance Fourier transform on the intermediate frequency signal to obtain a first Fourier transform result;
according to the first Fourier transform result, determining the frequency of a second echo signal returned by the corner reflector, wherein the second echo signal is an echo received by the millimeter wave radar;
determining the distance between the corner reflector and the millimeter wave radar according to the frequency of a second echo signal returned by the corner reflector;
doppler Fourier transform is carried out on the intermediate frequency signal, and a second Fourier transform result is obtained;
Determining Doppler frequency shift of the intermediate frequency signal according to the second Fourier transform result;
and determining the angle of the corner reflector in the view angle of the millimeter wave radar according to the Doppler frequency shift of the intermediate frequency signal.
3. The joint calibration method of claim 2, wherein determining the frequency of the second echo signal returned by the corner reflector based on the first fourier transform result comprises:
searching the frequency of the peak from the first Fourier transform result, and determining the frequency of the peak as the frequency of a second echo signal returned by the corner reflector;
said determining the doppler shift of said intermediate frequency signal based on said second fourier transform result comprises:
searching the frequency shift of the peak from the second Fourier transform result, and determining the frequency shift of the peak as the Doppler frequency shift of the intermediate frequency signal.
4. The joint calibration method of claim 1, wherein determining the distance of the corner reflector from the lidar based on the plurality of first echo signals comprises:
determining a first echo signal returned by the corner reflector from the plurality of first echo signals;
And determining the distance between the corner reflector and the laser radar according to the time difference between the laser radar transmitting signal and the first echo signal returned by the corner reflector.
5. The joint calibration method of claim 4, wherein determining the first echo signal returned by the corner reflector from the plurality of first echo signals comprises:
acquiring the saturation degree of echo intensities of the plurality of first echo signals;
and determining the first echo signal with the largest saturation degree of the echo intensity as the first echo signal returned by the corner reflector.
6. The joint calibration method according to claim 1, wherein one first position information group includes position information of the corner reflector in the millimeter wave radar coordinate system and position information of the corner reflector in the laser radar coordinate system when in one position, respectively, the corner reflector is sequentially arranged at N different positions, the N different positions correspond to the N first position information groups, and N is an integer greater than 1; the determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively comprises:
Calculating respective residual errors of the N first position information groups according to the N first position information groups and the first optimization parameters;
accumulating the residual errors of each of the N first position information groups to obtain a first accumulation sum;
and adjusting the first optimization parameters so that the first accumulation sum is minimum, wherein the optimization parameters when the first accumulation sum is minimum are the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system.
7. A joint calibration method according to any one of claims 1 to 6, further comprising:
acquiring absolute position information of the corner reflector;
converting the absolute position information of the corner reflector into an ENU coordinate system to obtain the position information of the corner reflector in the ENU coordinate system, wherein the ENU coordinate system is determined based on any position in the sensing range of the millimeter wave radar and the laser radar;
determining the pose of the millimeter wave radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the millimeter wave radar coordinate system;
determining the absolute pose of the millimeter wave radar according to the pose of the millimeter wave radar relative to the ENU coordinate system;
Determining the pose of the laser radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the laser radar coordinate system;
and determining the absolute pose of the laser radar according to the pose of the laser radar sensor relative to the ENU coordinate system.
8. The joint calibration method according to claim 7, wherein one second position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the millimeter wave radar coordinate system, respectively, at one position, one third position information group includes position information of the corner reflector in the ENU coordinate system and position information of the corner reflector in the laser radar coordinate system, respectively, at one position, the corner reflector being sequentially disposed at N different positions, the N different positions corresponding to the N second position information groups and the N third position information groups, N being an integer greater than 1; the determining the pose of the millimeter wave radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the millimeter wave radar coordinate system respectively comprises:
Calculating respective residual errors of the N second position information groups according to the N second position information groups and the second optimization parameters;
accumulating the residual errors of each of the N second position information groups to obtain a second accumulated sum;
adjusting the second optimization parameters so that the second accumulation sum is minimum, wherein the second optimization parameters when the second accumulation sum is minimum are the pose of the millimeter wave radar relative to the ENU coordinate system;
the determining the pose of the laser radar relative to the ENU coordinate system according to the position information of the corner reflector in the ENU coordinate system and the position information of the corner reflector in the laser radar coordinate system comprises:
calculating respective residual errors of the N third position information groups according to the N third position information groups and third optimization parameters;
accumulating the residual errors of each of the N third position information groups to obtain a third accumulation sum;
and adjusting the third optimization parameters so that the third accumulation sum is minimum, wherein the third optimization parameters when the third accumulation sum is minimum are the pose of the laser radar relative to the ENU coordinate system.
9. The utility model provides a millimeter wave radar and laser radar's joint calibration device which characterized in that is provided with the corner reflector in millimeter wave radar with laser radar's perception scope, joint calibration device includes:
The signal acquisition module is used for acquiring the intermediate frequency signals received by the millimeter wave radar and a plurality of first echo signals received by the laser radar;
the position determining module is used for determining the position information of the corner reflector in a millimeter wave radar coordinate system according to the intermediate frequency signal;
a distance determining module, configured to determine, according to the plurality of first echo signals, a distance between the corner reflector and the lidar, where the distance between the corner reflector and the lidar and an angle of the corner reflector in a view angle of the lidar are location information of the corner reflector in a lidar coordinate system;
and the pose determining module is used for determining the relative pose between the millimeter wave radar coordinate system and the laser radar coordinate system according to the position information of the corner reflector in the millimeter wave radar coordinate system and the position information in the laser radar coordinate system respectively.
10. Terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the joint calibration method according to any one of claims 1 to 8 when the computer program is executed.
11. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the joint calibration method according to any one of claims 1 to 8.
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| CN117310635B (en) * | 2023-11-29 | 2024-02-02 | 南京隼眼电子科技有限公司 | Radar compensation method, radar compensation device, radar equipment and storage medium |
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