Calibration method, calibration device and calibration equipment for installation angle of in-cabin radar and computer readable storage medium

Abstract

The invention relates to an in-cabin radar installation angle calibration method, calibration device and calibration equipment and a computer readable storage medium. The calibration method for the installation angle of the radar in the cabin comprises the following steps: S1, selecting at least three positions which are not on the same straight line in the cabin; s2, acquiring static target coordinate values of at least three positions in a vehicle coordinate system; s3, Doppler generators are arranged at at least three positions to simulate a moving target; s4, obtaining a moving target coordinate value of the Doppler generator under the radar coordinate system; and S5, calculating a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value. According to the invention, calibration of the in-cabin radar installation angle can be effectively realized.

Description

Technical Field

[0001] The present invention relates to the field of radar application technology, and in particular to a calibration method, a calibration device, a calibration equipment and a computer-readable storage medium for calibrating the installation angle of a cabin radar. Background Art

[0002] At present, radar is increasingly used in cabins and plays an increasingly important role. For example, in terms of child retention detection, radar can monitor in real time whether a child is accidentally left behind in the car, providing protection for the safety of the child. Occupancy detection can accurately determine whether a seat is occupied, providing a basis for vehicle passenger management and resource allocation. Intrusion detection can promptly detect illegal entry into the vehicle and enhance vehicle safety.

[0003] Although the radar can measure the target position relative to the radar coordinate system, in order to obtain the target position in the vehicle coordinate system, in order to accurately determine whether the target is in the vehicle and determine the exact position of the target, it is necessary to know the installation posture of the radar. This is because different installation postures will cause the radar's measurement results of the target position to have different performances in the vehicle coordinate system. If the installation posture of the radar can be determined, the target position relative to the radar coordinate system can be converted to the position in the vehicle coordinate system through methods such as coordinate conversion, thereby better meeting the needs of practical applications.

[0004] However, it is not easy to measure the installation angle of the radar. On the one hand, the space inside the cabin is usually complex, and there may be various obstacles and interference factors, which brings great challenges to the accurate measurement of the installation angle. On the other hand, the measurement of the installation angle requires high-precision measurement equipment and professional technicians, which may increase costs and operational difficulties in practical applications. Summary of the invention

[0005] In view of the above problems in the prior art, the present invention proposes a calibration method, a calibration device, a calibration equipment and a computer-readable storage medium for the installation angle of an in-cabin radar, which can effectively realize the calibration of the installation angle of the in-cabin radar.

[0006] Specifically, the present invention proposes a method for calibrating the installation angle of a radar in a cabin, comprising the following steps:

[0007] S1, selecting at least three positions in the cabin that are not in a straight line;

[0008] S2, obtaining the static target coordinate values ​​of the at least three positions in the vehicle coordinate system;

[0009] S3, setting a Doppler generator at the at least three positions to simulate a moving target;

[0010] S4, obtaining the moving target coordinate value of the Doppler generator in the radar coordinate system;

[0011] S5, calculating a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value.

[0012] According to an embodiment of the present invention, in step S2, a ruler or a rangefinder is used to measure the static target coordinate values ​​of the at least three positions in the vehicle coordinate system.

[0013] According to one embodiment of the present invention, the Doppler generator is a small fan.

[0014] According to one embodiment of the present invention, obtaining the moving target coordinate values ​​of the at least three positions in the radar coordinate system includes the steps of:

[0015] S41, controlling the radar in the cabin to transmit a signal of a specific waveform;

[0016] S42, receiving the radar echo of the Doppler generator and performing intermediate frequency sampling;

[0017] S43, performing fast and slow time dimension FFT on the sampling result;

[0018] S44, coherent accumulation between channels to obtain RAMAP;

[0019] S45, detecting the Doppler generator by using the radar;

[0020] S46, calculating the distance, horizontal angle and elevation angle of the Doppler generator;

[0021] S47, calculating the moving target coordinate value of the Doppler generator based on the distance, horizontal angle and pitch angle of the Doppler generator.

[0022] According to one embodiment of the present invention, after executing step S43 and before executing step S44, a suppression process is performed on the static target in the cabin.

[0023] According to one embodiment of the present invention, steps S45 and S46 are repeated to average the multiple calculation results.

[0024] According to one embodiment of the present invention, in step S47, the distance R, the horizontal angle θ and the pitch angle of the Doppler generator are set as follows: Then the calculation formula of the moving target coordinate value (x, y, z) is:

[0025]

[0026] The present invention also provides a device for calibrating the installation angle of a cabin radar, which is used to implement the calibration method of the installation angle of the cabin radar, comprising:

[0027] A selection unit, used for selecting at least three positions in the cabin that are not in a straight line;

[0028] A first acquisition unit, used to acquire the static target coordinate values ​​of the at least three positions in the vehicle coordinate system;

[0029] A second acquisition unit is used to acquire the moving target coordinate values ​​of the at least three positions in the radar coordinate system;

[0030] A calculation unit calculates a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value.

[0031] The present invention also provides a calibration device for the installation angle of a radar in a cabin, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned calibration methods when executing the computer program.

[0032] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the calibration method as described in any one of the above items.

[0033] The present invention provides a calibration method, a calibration device, a calibration equipment and a computer-readable storage medium for the installation angle of an in-cabin radar. By obtaining the static target coordinate values ​​of at least three positions in the cabin in a vehicle coordinate system and the moving target coordinate values ​​in a radar coordinate system, a conversion matrix from the radar coordinate system to the vehicle coordinate system is calculated based on the static target coordinate values ​​and the moving target coordinate values, thereby effectively realizing the calibration of the installation angle of the in-cabin radar.

[0034] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are included to provide further explanation of the present invention, and are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principle of the present invention.

[0036] In the attached figure:

[0037] Figure 1 A flowchart of a method for calibrating the installation angle of a radar in a cabin according to an embodiment of the present invention is shown.

[0038] Figure 2A top view of three selected locations within a cabin is shown according to one embodiment of the present invention.

[0039] Figure 3 A schematic structural diagram of a device for calibrating the installation angle of a radar in a cabin according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0042] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0043] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0044] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0045] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0046] Figure 1 A flowchart of a method for calibrating the installation angle of a radar in a cabin of a vehicle according to an embodiment of the present invention is shown. As shown in the figure, a method for calibrating the installation angle of a radar in a vehicle cabin comprises the following steps:

[0047] S1, select at least three positions in the cabin that are not on a straight line. If there are only two positions, then we can only determine the position relationship of the target on the straight line connecting the two points, and there are countless possible spatial positions. Three points that are not on the same straight line can form a plane. By observing at these positions, a reference frame of three-dimensional space can be established. Figure 2 The top view of three selected positions in a cabin of an embodiment of the present invention is shown. As shown in the figure, in this example, a vehicle 200 includes two front seats 201 and one rear seat 202. The X-axis and Y-axis of the vehicle coordinate system intersect, and the Z-axis is perpendicular to the paper surface, and the center O of the vehicle coordinate system is set. Three position points 203 are selected at different heights in the Z-axis direction of the rear seat 202 of the vehicle.

[0048] S2, obtaining the coordinate values ​​of static targets at at least three positions in the vehicle coordinate system;

[0049] S3, setting up Doppler generators at at least three locations to simulate a moving target;

[0050] S4, obtaining the moving target coordinate value of the Doppler generator in the radar coordinate system;

[0051] S5, calculate the conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate values ​​and the moving target coordinate values. In the vehicle environment, the radar coordinate system and the vehicle coordinate system are two different reference systems. In order to accurately correspond the target information detected by the radar to the vehicle's own coordinate system, so as to facilitate subsequent various application operations such as occupancy detection in the warehouse, intrusion detection, child safety, etc., it is necessary to find the conversion relationship between the two, and this conversion relationship can be represented by the calculated conversion matrix. In other words, obtaining the conversion matrix realizes the calibration of the installation angle of the radar in the vehicle cabin.

[0052] In some examples, in step S2, a ruler or a rangefinder is used to measure the coordinate values ​​of the static target at at least three positions in the vehicle coordinate system.

[0053] In some examples, the Doppler generator is a small fan. As an example and not a limitation, a device similar to a small fan with a rotating motor can be selected as a Doppler generator. The rotating motor is equipped with a signal transmitting device mounted on its shaft, such as a small microwave transmitter or a laser transmitter. When the motor rotates, the transmitting device performs a circular motion around the motor shaft. During the circular motion, the position of the transmitting device changes continuously relative to the fixed receiver (radar) in the cabin, resulting in relative motion, thereby causing the Doppler effect. By adjusting the speed of the motor, the change in signal frequency can be accurately controlled to facilitate quantitative analysis of the Doppler frequency shift.

[0054] In some examples, obtaining moving target coordinate values ​​at at least three positions in a radar coordinate system includes the steps of:

[0055] S41, the radar in the control cabin emits a signal of a specific waveform. Different waveform signals have different characteristics. By selecting and transmitting a signal of a specific waveform, it can meet the needs of various detection targets in the cabin in a targeted manner.

[0056] S42, receiving the radar echo from the Doppler generator and performing intermediate frequency sampling. Usually, the echo signal received by the radar is a high-frequency signal, and it is relatively complicated to process it directly and has high hardware requirements. Therefore, the high-frequency echo signal must first be converted into an intermediate frequency signal by mixing and other methods. The frequency of the intermediate frequency signal is much lower than that of the original high-frequency signal, but it still retains the key information in the echo, such as the Doppler frequency shift of the target (related to the speed of the simulated moving target). Afterwards, the sampling theorem is used to sample the intermediate frequency signal at a certain sampling frequency, and the continuous analog intermediate frequency signal is converted into a discrete digital signal sequence, so that it can be further analyzed by digital signal processing methods.

[0057] S43, performing fast time and slow time dimension FFT on the sampling results. By combining fast time and slow time dimension FFT, two key information, the distance and speed of the target, can be extracted from the radar echo sampling results at the same time, which is conducive to accurately grasping the state of the simulated moving target in the vehicle cabin.

[0058] S44, coherent accumulation between channels to obtain RAMAP. Coherent accumulation between channels is conducive to improving the signal-to-noise ratio, and RAMAP can display the full picture of the target in the vehicle cabin in the form of an intuitive two-dimensional image.

[0059] S45, detection of Doppler generator by radar;

[0060] S46, calculating the distance, horizontal angle and pitch angle of the Doppler generator. Based on the detection result of step S45, the distance, horizontal angle and pitch angle of each moving target are calculated respectively.

[0061] S47, calculating the moving target coordinate value of the Doppler generator based on the distance, horizontal angle and pitch angle of the Doppler generator.

[0062] In some examples, after executing step S43 and before executing step S44, static targets in the cabin are suppressed to remove frequency components corresponding to the static targets, thereby improving the accuracy and reliability of the radar's detection of dynamic targets in the cabin.

[0063] In some examples, steps S45 and S46 are repeated to average the multiple calculation results. The distance, horizontal angle, and pitch angle obtained by averaging the multiple calculation results can more accurately reflect the actual position of the Doppler generator (simulating a moving target) in the vehicle cabin.

[0064] In some examples, in step S47, the distance R, the horizontal angle θ and the pitch angle of the Doppler generator are assumed to be Then the calculation formula of the moving target coordinate value (x, y, z) is:

[0065]

[0066] It is easy to understand that in step S2, the static target coordinate values ​​of the three static targets in the vehicle coordinate system can be obtained: In step S4, the moving target coordinate values ​​of the three moving targets in the radar coordinate system are obtained. Thus, the equation group can be constructed and solved to obtain the transformation matrix from the radar coordinate system to the vehicle coordinate system: T = CR -1 , complete the calibration of the radar installation position in the cabin.

[0067] Figure 3The structure diagram of a calibration device for the installation angle of a cabin radar according to an embodiment of the present invention is shown. As shown in the figure, a calibration device 300 for the installation angle of a cabin radar is used to implement the calibration method for the installation angle of the cabin radar described above. The calibration device 300 includes:

[0068] A selection unit 301 is used to select at least three positions in the cabin that are not in a straight line;

[0069] A first acquisition unit 302 is used to acquire the coordinate values ​​of static targets at at least three positions in the vehicle coordinate system;

[0070] The second acquisition unit 303 is used to acquire the moving target coordinate values ​​of at least three positions in the radar coordinate system;

[0071] The calculation unit 304 calculates a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value.

[0072] The present invention also provides a device for calibrating the installation angle of an in-cabin radar, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any of the aforementioned methods for calibrating the installation angle of an in-cabin radar are implemented.

[0073] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any of the aforementioned methods for calibrating the installation angle of the in-cabin radar are implemented.

[0074] Among them, the specific implementation methods and technical effects of the calibration device for the installation angle of the in-cabin radar, the calibration equipment for the installation angle of the in-cabin radar, and the computer-readable storage medium can all be referred to the embodiments of the detection method provided by the above-mentioned present invention, and will not be repeated here.

[0075] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0076] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration.

[0077] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0078] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0079] It will be apparent to those skilled in the art that various modifications and variations may be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A method for calibrating the installation angle of a radar in a vehicle cabin, comprising the following steps: S1, selecting at least three positions in the cabin that are not in a straight line; S2, obtaining the static target coordinate values ​​of the at least three positions in the vehicle coordinate system; S3, setting a Doppler generator at the at least three positions to simulate a moving target; S4, obtaining the moving target coordinate value of the Doppler generator in the radar coordinate system; S5, calculating a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value.

2. The calibration method according to claim 1, characterized in that: In step S2, a ruler or a rangefinder is used to measure the static target coordinate values ​​of the at least three positions in the vehicle coordinate system.

3. The calibration method according to claim 1, characterized in that: The Doppler generator is a small fan.

4. The calibration method according to claim 1, characterized in that: Obtaining the moving target coordinate values ​​of the at least three positions in the radar coordinate system comprises the steps of: S41, controlling the radar in the cabin to transmit a signal of a specific waveform; S42, receiving the radar echo of the Doppler generator and performing intermediate frequency sampling; S43, performing fast and slow time dimension FFT on the sampling result; S44, coherent accumulation between channels to obtain RAMAP; S45, detecting the Doppler generator by using the radar; S46, calculating the distance, horizontal angle and elevation angle of the Doppler generator; S47, calculating the moving target coordinate value of the Doppler generator based on the distance, horizontal angle and pitch angle of the Doppler generator.

5. The calibration method according to claim 4, characterized in that: After executing step S43 and before executing step S44, a suppression process is performed on the static target in the cabin.

6. The calibration method according to claim 4, characterized in that: Repeat steps S45 and S46 to average the multiple calculation results.

7. The calibration method according to claim 4, characterized in that: In step S47, the distance R, horizontal angle θ and pitch angle of the Doppler generator are set Then the calculation formula of the moving target coordinate value (x, y, z) is:

8. A calibration device for the installation angle of a cabin radar, used to implement the calibration method for the installation angle of a cabin radar according to claim 1, characterized in that: include: A selection unit, used for selecting at least three positions in the cabin that are not in a straight line; A first acquisition unit, used to acquire the static target coordinate values ​​of the at least three positions in the vehicle coordinate system; A second acquisition unit is used to acquire the moving target coordinate values ​​of the at least three positions in the radar coordinate system; A calculation unit calculates a conversion matrix from the radar coordinate system to the vehicle coordinate system based on the static target coordinate value and the moving target coordinate value.

9. A device for calibrating the installation angle of a radar in a cabin, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the calibration method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the calibration method according to any one of claims 1 to 7 are implemented.

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