Self-adaptive adjustment method and device for scanning point number

Abstract

The invention relates to a scanning point number self-adaptive adjusting method and a scanning point number self-adaptive adjusting device. The method is applied to a scanning system of a millimeter wave radar, and comprises the following steps: obtaining scanning distances of all target points in a previous scanning period; the scanning distance is the distance from the millimeter wave radar to the target point; determining an included angle of each target point pair in the previous scanning period based on the scanning distances of all target points in the previous scanning period, the pitch angle of the millimeter wave radar, the horizontal angle corresponding to each target point and the position of the millimeter wave radar; and based on the included angle of each target point pair in the previous scanning period and the beam width of the transmitting antenna of the millimeter-wave radar, adjusting the number of periodic scanning points of the millimeter-wave radar to obtain the number of periodic scanning points of the current scanning period. By adopting the method, the scanning point number of scanning is automatically adjusted, and the problems of high overlapping rate of adjacent sampling points and poor edge imaging effect are solved.

Description

Technical Field

[0001] This application relates to the field of radar scanning technology, and in particular to a method and apparatus for adaptive adjustment of the number of scanning points. Background Technology

[0002] With the development of electronic technology, millimeter-wave radar, as a spatial three-dimensional sensing sensor, has been widely used in surveying, autonomous driving, and 3D modeling. For example, 3D scanning radar, because it does not require the installation of traditional optical lenses and is not affected by dust, can be used in high-temperature, high-pressure, and high-dust environments as an industrial instrument to measure the height and volume of stored materials in tanks and silos.

[0003] Existing millimeter-wave radar scanning methods cannot adjust the number of scanning points based on different elevation angles or scan sizes. When the elevation angle is small and the scan radius is small, there is a problem of high overlap between adjacent sampling points; when the elevation angle is large and the scan radius is large, there is a problem of poor imaging results due to the excessive distance between adjacent sampling points.

[0004] Existing technologies cannot adaptively adjust the number of scanning points per cycle, resulting in problems such as high overlap between adjacent sampling points or poor imaging quality due to excessive distance between adjacent sampling points. No effective solution has yet been proposed. Summary of the Invention

[0005] Therefore, it is necessary to provide a method and apparatus for adaptive adjustment of the number of scan points to address the aforementioned technical problems.

[0006] In a first aspect, this application provides an adaptive adjustment method for the number of scanning points, applied to a scanning system of millimeter-wave radar, the method comprising:

[0007] Obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process;

[0008] Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, the included angle of each target point pair in the previous scanning cycle is determined; the target point pair is a pair of points determined by pairing adjacent target points in the scanning sequence; the included angle of the target point pair is the angle difference between the two sampling directions corresponding to the target point pair;

[0009] Based on the included angles of each target point pair in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the number of periodic scanning points of the millimeter-wave radar is adjusted to obtain the number of periodic scanning points in the current scanning cycle; the number of periodic scanning points is the number of scanning points of the millimeter-wave radar in one scanning cycle.

[0010] In one embodiment, obtaining the scanning distance of all target points in the previous scanning cycle includes:

[0011] The millimeter-wave radar performs a first Fourier transform on the target reflection echo signals received from each target point in the previous scanning cycle to obtain the first Fourier transform signal corresponding to each target point; the target reflection echo signal is the signal returned after reflection at the target point by the electromagnetic wave emitted by the millimeter-wave radar during the scanning process.

[0012] Determine the maximum modulus value in the signal after the first Fourier transform corresponding to each target point, and use it as the first modulus value corresponding to each target point;

[0013] After performing an inverse Fourier transform on the received target reflected echo signals from each of the target points, downsampling is performed to obtain the downsampled signals corresponding to each of the target points.

[0014] A second Fourier transform is performed on the downsampled signal corresponding to each of the target points to obtain the signal after the second Fourier transform corresponding to each of the target points;

[0015] Determine the maximum modulus value in the signal after the second Fourier transform corresponding to each target point, and use it as the second modulus value corresponding to each target point;

[0016] Based on the first modulus value corresponding to each target point, the second modulus value corresponding to each target point, the preset distance resolution, and the resolution enhancement factor, the scanning distance of all target points in the previous scanning cycle is determined.

[0017] In one embodiment, before performing a first Fourier transform on the target reflected echo signals received by the millimeter-wave radar from each target point in the previous scanning cycle to obtain the first Fourier transformed signals corresponding to each target point, the process includes:

[0018] The received target reflected echo signals from each of the target points are windowed to obtain the windowed signals corresponding to each of the target points;

[0019] The windowed signal corresponding to each target point is subjected to complex modulation to obtain the complex modulated signal corresponding to each target point.

[0020] In one embodiment, before performing inverse Fourier transform on the received target reflected echo signals of each of the target points and then downsampling them to obtain the downsampled signals corresponding to each of the target points, the process includes:

[0021] The spectrum of the signal after the first Fourier transform corresponding to each target point is shifted to obtain the spectrum-shifted signal corresponding to each target point.

[0022] The spectrum-shifted signals corresponding to each target point are subjected to low-pass filtering to obtain the low-pass filtered signals corresponding to each target point.

[0023] In one embodiment, determining the included angle between each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar includes:

[0024] Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point, the coordinates of each target point in the previous scanning cycle are determined.

[0025] Based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, the included angle of each pair of target points in the previous scanning cycle is determined.

[0026] In one embodiment, determining the coordinates of each target point in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point includes:

[0027] Based on the scanning distances of all target points in the previous scanning cycle and the elevation angle of the millimeter-wave radar, the projected distances of the scanning distances of all target points in the previous scanning cycle onto the radar plane, and the height of each target point are determined; the height of the target point is the vertical distance from the target point to the radar plane; the radar plane is the millimeter-wave transmission plane determined in the millimeter-wave radar coordinate system when the rotation axis of the millimeter-wave radar transmission center is perpendicular to the horizontal plane;

[0028] Based on the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, and the horizontal angle corresponding to each target point, the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system in the previous scanning cycle are determined.

[0029] Based on the height of each target point in the previous scanning cycle, and the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system, the coordinates of each target point in the previous scanning cycle are determined.

[0030] In one embodiment, determining the included angle between pairs of target points in the previous scanning cycle based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points includes:

[0031] Based on the coordinates of each target point in the previous scanning cycle, the distance between each pair of target points in the previous scanning cycle is determined; the distance between the two target points determined by the pair of target points is the distance between the two target points.

[0032] Based on the distances between each pair of target points in the previous scanning cycle and the scanning distances of all target points, the included angles between each pair of target points in the previous scanning cycle are determined.

[0033] In one embodiment, adjusting the number of periodic scan points of the millimeter-wave radar based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar to obtain the number of periodic scan points in the current scanning cycle includes:

[0034] Based on the included angle of each pair of target points in the previous scanning cycle, determine the average value of the included angle of each pair of target points in the previous scanning cycle;

[0035] Based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, the number of periodic scanning points of the millimeter-wave radar is adjusted to obtain the number of periodic scanning points in the current scanning cycle.

[0036] In one embodiment, adjusting the number of periodic scan points of the millimeter-wave radar based on the difference between the average angle of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna to obtain the number of periodic scan points in the current scanning cycle includes:

[0037] When the average angle of each target point pair in the previous scanning cycle is greater than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan points of the millimeter-wave radar is increased based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of periodic scan points in the current scanning cycle.

[0038] When the average angle of each target point pair in the previous scanning cycle is less than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan points of the millimeter-wave radar is reduced based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of periodic scan points in the current scanning cycle.

[0039] Secondly, this application also provides a scanning point number adaptive adjustment device. Applied to a scanning system for millimeter-wave radar, the device includes:

[0040] The distance determination module is used to obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process;

[0041] Angle determination module is used to determine the angle between each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar; the target point pair is a pair of points determined by pairing adjacent target points in the scanning sequence; the angle between the target point pairs is the angle difference between the two sampling directions corresponding to the target point pair;

[0042] And an adjustment module, used to adjust the number of scanning points of the millimeter-wave radar based on the included angle of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, to obtain the number of scanning points in the current scanning cycle; the number of scanning points is the number of scanning points of the millimeter-wave radar in one scanning cycle.

[0043] Thirdly, this application also provides a scanning system for millimeter-wave radar. The system includes a gimbal, a millimeter-wave radar, and a main control module;

[0044] The gimbal is connected to the main control module and is used to rotate in response to received control commands;

[0045] The millimeter-wave radar is connected to the main control module and fixed on the gimbal, rotating as the gimbal rotates.

[0046] The main control module is used to control the gimbal and the millimeter-wave radar to operate according to the adaptive adjustment method for the number of scanning points described in the first aspect above.

[0047] The aforementioned adaptive adjustment method and apparatus for the number of scanning points obtains the scanning distances of all target points in the previous scanning cycle. Then, based on the scanning distances of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, it determines the included angles of each pair of target points in the previous scanning cycle. Based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, it updates the number of scanning points of the millimeter-wave radar to obtain the number of scanning points in the current scanning cycle. By adjusting the periodic scanning point count through the relationship between the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, the adjusted periodic scanning point count is suitable for the current elevation angle. This achieves automatic adjustment of the number of scanning points on the scanning surface, solving the problems of high overlap rates between adjacent sampling points or poor edge imaging effects caused by excessive distances between adjacent sampling points in existing technologies.

[0048] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0049] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0050] Figure 1 A hardware structure block diagram of a terminal for an adaptive adjustment method for the number of scan points provided in an embodiment of this application;

[0051] Figure 2 A flowchart of a method for adaptive adjustment of the number of scan points provided in an embodiment of this application;

[0052] Figure 3 A schematic diagram illustrating the relationship between the scanning distance of a target point and the elevation angle of a millimeter-wave radar, provided in an embodiment of this application;

[0053] Figure 4 A flowchart of a preferred embodiment of the scanning point number adaptive adjustment method provided in this application;

[0054] Figure 5This is a structural block diagram of a scanning point adaptive adjustment device provided in an embodiment of this application. Detailed Implementation

[0055] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0056] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this application do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. Words such as “connected,” “linked,” and “coupled” used in this application are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific order of objects.

[0057] The method embodiments provided in this example can be executed on a terminal, computer, or similar computing device. For example, it can run on a terminal. Figure 1 This is a hardware structure block diagram of the terminal for the adaptive adjustment of scan points in this embodiment. For example... Figure 1 As shown, a terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 and a memory 104 for storing data are also included. The processor 102 may be, but is not limited to, a microprocessor (MCU) or a programmable logic device (FPGA). The terminal may also include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that… Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the terminal described above. For example, the terminal may also include components that are larger than... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown are illustrated.

[0058] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the scan point adaptive adjustment method in this embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0059] The transmission device 106 is used to receive or send data via a network. This network includes a wireless network provided by the terminal's communication provider. In one example, the transmission device 106 includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 106 can be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0060] This embodiment provides an adaptive adjustment method for the number of scanning points, applied to the scanning system of millimeter-wave radar. Figure 2 This is a flowchart of the adaptive adjustment method for the number of scan points in this embodiment, as shown below. Figure 2 As shown, the process includes the following steps:

[0061] Step S210: Obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process.

[0062] The aforementioned "previous scan cycle" refers to the scan cycle preceding the current scan cycle, i.e., the previous frame of the millimeter-wave radar. The aforementioned target object can be an entity within the detection range of the millimeter-wave radar that has been designated by the millimeter-wave radar's scanning system as requiring detection, identification, or tracking. The aforementioned target object can be: a human body (pedestrian, passenger, worker, etc.), a vehicle, an obstacle (box, railing, wall, etc.), or a specific component (robotic arm end effector, tool, cargo, etc.). The aforementioned distance from the millimeter-wave radar to the target point is the straight-line distance from the millimeter-wave radar's transmitter to the target point. Obtaining the scanning distances of all target points within the previous scan cycle can be achieved by determining the scanning distances of all target points within the previous scan cycle based on the target reflected echo signals received by the millimeter-wave radar from each target point in the previous scan cycle.

[0063] Step S220: Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, determine the included angle of each target point pair in the previous scanning cycle; the target point pair is the pair of points determined by pairing adjacent target points in the scanning sequence; the included angle of the target point pair is the angle difference between the two sampling directions corresponding to the target point pair.

[0064] The elevation angle of the millimeter-wave radar mentioned above can be the vertical angle between the centerline of the electromagnetic wave emitted by the millimeter-wave radar and the horizontal plane. The horizontal angle corresponding to each target point mentioned above can be the horizontal angle (measured clockwise or counterclockwise) between the millimeter-wave radar in the horizontal plane and the target point from the reference direction (usually due north or directly in front of the radar). The value range of the above horizontal angles is 0° to 360° (or −180° to +180°, depending on the specific situation). The above method of determining the included angles of each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar can be achieved by determining the included angles of each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar. Furthermore, the included angles of each pair of target points in the previous scanning cycle can be determined based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points.

[0065] Step S230: Based on the included angles of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, adjust the periodic scanning point number of the millimeter-wave radar to obtain the periodic scanning point number cycle of the current scanning cycle; the number of scanning points is the number of scanning points of the millimeter-wave radar in one scanning cycle.

[0066] The above method, which adjusts the number of periodic scan points of the millimeter-wave radar based on the included angles of each target point pair in the previous scan cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, to obtain the number of periodic scan points in the current scan cycle, can be achieved by determining the average included angles of each target point pair in the previous scan cycle, and then adjusting the number of periodic scan points of the millimeter-wave radar based on the difference between the average included angles of each target point pair in the previous scan cycle and the beamwidth of the millimeter-wave radar's antenna, to obtain the number of periodic scan points in the current scan cycle.

[0067] Steps S210 to S230 above involve obtaining the scanning distances of all target points in the previous scanning cycle. Then, based on the scanning distances of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, the included angles of each pair of target points in the previous scanning cycle are determined. Based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the number of periodic scanning points of the millimeter-wave radar is updated to obtain the number of periodic scanning points in the current scanning cycle. By adjusting the number of periodic scanning points according to the relationship between the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the adjusted number of periodic scanning points is made suitable for the current elevation angle. This achieves automatic adjustment of the number of scanning points for the scanning area, solving the problems of high overlap rate of adjacent sampling points or poor edge imaging effect caused by excessive distance between adjacent sampling points in the prior art.

[0068] In one embodiment, step S210, obtaining the scanning distance of all target points in the previous scanning cycle, includes:

[0069] Step S211: Perform a first Fourier transform on the target reflection echo signals received by the millimeter-wave radar from each target point in the previous scanning cycle to obtain the signal after the first Fourier transform corresponding to each target point; the target reflection echo signal is the signal returned after reflection at the target point by the electromagnetic wave emitted by the millimeter-wave radar during the scanning process.

[0070] The aforementioned target reflection echo information can be ADC (Analog-to-Digital Converter) data, specifically a complex number including a real part and an imaginary part. Before performing the first Fourier transform on the target reflection echo signals received by the millimeter-wave radar from each target point in the previous scan cycle, the real parts of the received ADC data need to be added together, and the imaginary parts need to be added together, to accumulate the signal and obtain an accumulated signal S. Then, the accumulated signal S is subjected to the first Fourier transform to obtain the signal corresponding to each target point after the first Fourier transform. The signal after the first Fourier transform is a frequency domain signal.

[0071] Step S212: Determine the maximum modulus value in the signal after the first Fourier transform corresponding to each target point, and use it as the first modulus value corresponding to each target point.

[0072] The process of determining the maximum modulus of the signal after the first Fourier transform corresponding to each target point and using it as the first modulus for each target point can be achieved by first calculating the modulus of the signal after the first Fourier transform corresponding to each target point, specifically by calculating the modulus of the real and imaginary parts of each signal value in the FSBWT signal after the first Fourier transform, with the modulus of the real part denoted as... The imaginary part is denoted as Furthermore, the larger of the real and imaginary moduli is denoted as max, and the smaller as min. The modulus of each signal value in the FSBWT signal after the first Fourier transform is then calculated according to a preset formula. Calculations are performed, and then all moduli are selected. The maximum value in This is used as the first modulus value corresponding to each target point, and its index is denoted as MidMaxIdx.

[0073] The preset calculation formula is:

[0074] ;

[0075] in, Let T, a, and b be the modulus of each signal value in the signal FSBWT after the first Fourier transform, and let T, a, and b be the scaling factors. The following relationship needs to be satisfied: and .

[0076] Step S213: Perform inverse Fourier transform on the received target reflection echo signals of each target point and then downsample them to obtain the downsampled signals corresponding to each target point.

[0077] The above-mentioned downsampling of the received target reflection echo signals from each target point after performing an inverse Fourier transform (IFT) yields the downsampled signal corresponding to each target point. This can be achieved by performing an IFT on the received target reflection echo signals from each target point, transforming the frequency domain signals into time domain complex signals, and then taking a value at preset intervals for each time domain signal (i.e., downsampling the time domain signal corresponding to each target point). This downsampling reduces the amount of data and achieves lossless bandwidth reduction. It preserves low-frequency signals while the low-pass filter removes high-frequency components, avoiding interference caused by spectral aliasing.

[0078] Step S214: Perform a second Fourier transform on the downsampled signals corresponding to each target point to obtain the second Fourier transform signals corresponding to each target point.

[0079] Step S215: Determine the maximum modulus value in the signal after the second Fourier transform corresponding to each target point, and use it as the second modulus value corresponding to each target point.

[0080] In this step, determining the maximum modulus of the signal after the second Fourier transform corresponding to each target point and using it as the second modulus corresponding to each target point can be achieved by first calculating the modulus of the signal after the second Fourier transform corresponding to each target point, calculating the modulus of the real and imaginary parts of each signal value in the signal after the second Fourier transform, then selecting the larger and smaller values ​​of the real and imaginary modulus, and calculating the modulus of each signal value in the signal after the second Fourier transform according to a preset calculation formula, then selecting the maximum value among all modulus values ​​and using it as the second modulus corresponding to each target point, and recording its index as FindMaxIdx.

[0081] Step S216: Based on the first modulus value corresponding to each target point, the second modulus value corresponding to each target point, the preset distance resolution, and the resolution enhancement factor, determine the scanning distance of all target points in the previous scanning cycle.

[0082] In this step, the calculation process for determining the scan distance EstRange of all target points in the previous scan cycle is as follows:

[0083] ;

[0084] Where FindMaxIdx is the second modulus value corresponding to the target point, and MidMaxIdx is the first modulus value corresponding to the target point. Where is the distance resolution, and W is the resolution enhancement factor.

[0085] Steps S211 to S216 above involve performing a first Fourier transform on the target reflection echo signals received by the millimeter-wave radar from each target point in the previous scanning cycle to determine the first modulus value corresponding to each target point. Then, an inverse Fourier transform is performed on the received target reflection echo signals from each target point, followed by downsampling. Finally, a second Fourier transform is performed on the downsampled signals corresponding to each target point to obtain the second Fourier transform signal corresponding to each target point, and the second modulus value corresponding to each target point is determined. By determining the first and second modulus values, the scanning distance of all target points in the previous scanning cycle is determined. This determination of the scanning distance facilitates subsequent adjustment of the number of scanning points of the millimeter-wave radar based on the scanning distance, thus obtaining the number of scanning points for the current scanning cycle.

[0086] Specifically, in one embodiment, prior to step S211, the following is included:

[0087] Step S2101: Window the received target reflection echo signals from each target point to obtain the windowed signal corresponding to each target point.

[0088] The above-mentioned windowing of the received target reflected echo signals from each target point to obtain the windowed signal corresponding to each target point can be achieved by windowing the accumulated signal. Specifically, windowing the accumulated signal can be done by multiplying the real and imaginary parts of the accumulated signal S with the BlackmanWindow function to obtain the windowed signal SBW.

[0089] It suppresses spectral leakage in the subsequent first Fourier transform by windowing the target reflection echo signal at each target point.

[0090] Step S2102: Perform complex modulation on the windowed signal corresponding to each target point to obtain the complex modulated signal corresponding to each target point.

[0091] In this step, the windowed signals corresponding to each of the above target points are subjected to complex modulation to obtain the complex modulated signals corresponding to each target point. This can be achieved by using a preset complex modulation formula to perform complex modulation on the windowed signals. The preset complex modulation formula is as follows:

[0092] ;

[0093] Where SBWT(m) is the signal after complex modulation of signal point m, m is the index of a single signal point, ranging from 0 to N, N is the total number of sampling points, and SBW(m) is the signal after windowing of signal point m. The signal sampling rate, For the intermediate frequency of the signal, The calculation process is as follows:

[0094] ;

[0095] in, To define the minimum value within the frequency range of the analysis, This is to define the maximum value within the frequency range of the analysis.

[0096] The aforementioned complex modulation of the windowed signal is intended to shift the center frequency of interest to 0Hz in the future, thereby avoiding negative frequency aliasing during the subsequent first Fourier transform. This allows for the use of fewer data points and saves computational power.

[0097] Steps S2101 to S2102 above involve windowing the target reflected echo signals received from each target point to obtain the windowed signal corresponding to each target point, and then performing complex modulation on the windowed signal corresponding to each target point to obtain the complex modulated signal corresponding to each target point. This process aims to suppress spectral leakage in the subsequent first Fourier transform and save computing power.

[0098] Additionally, in one embodiment, prior to step S213, the following steps are included:

[0099] Step S2121: Spectrum shifting is performed on the signals after the first Fourier transform corresponding to each target point to obtain the spectrum shifted signals corresponding to each target point.

[0100] The aforementioned spectral shifting of the signals corresponding to the first Fourier transform at each target point can be achieved by multiplying the signals corresponding to the first Fourier transform at each target point by... This yields the spectral shifted signals corresponding to each target point. The signal sampling rate, This is the intermediate frequency of the signal. It is achieved by multiplying the signal obtained from the first Fourier transform of each target point by... This is done to move the signals corresponding to each target point after the first Fourier transform back to their original positions. Moving them back to their original positions involves moving the signals that have been shifted to near 0Hz after complex modulation (spectral shifting) back to their original center frequency f0.

[0101] Step S2122: Perform low-pass filtering on the spectrum-shifted signals corresponding to each target point to obtain the low-pass filtered signals corresponding to each target point.

[0102] In this step, the aforementioned low-pass filtering of the spectrum-shifted signals corresponding to each target point to obtain the low-pass filtered signals for each target point can be achieved by using a low-pass filter to perform low-pass filtering on the spectrum-shifted signals corresponding to each target point. The aforementioned low-pass filter can be a dielectric frequency... satisfy The low-pass filter. Among them, the above... Where is the sampling rate, and W is the resolution enhancement factor. A low-pass filter ensures that the frequencies after spectrum shifting are not interfered with by aliasing.

[0103] Steps S2121 to S2122 above involve spectrum shifting of the signals after the first Fourier transform corresponding to each target point to obtain spectrum-shifted signals for each target point. Then, low-pass filtering is applied to the spectrum-shifted signals corresponding to each target point to obtain low-pass filtered signals for each target point. By performing spectrum shifting on the signals after the first Fourier transform corresponding to each target point and low-pass filtering on the shifted signals, low-pass filtered signals are obtained, thus preventing the frequencies after spectrum transformation from being interfered with due to spectrum aliasing.

[0104] In one embodiment, step S220, based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, determines the included angle of each pair of target points in the previous scanning cycle, including:

[0105] Step S222: Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point, determine the coordinates of each target point in the previous scanning cycle.

[0106] The above method, which determines the coordinates of each target point in the previous scan cycle based on the scanning range of all target points, the elevation angle of the millimeter-wave radar, and the corresponding horizontal angle of each target point, can be achieved by determining the projected distance of the scanning range of all target points in the previous scan cycle onto the radar plane, as well as the height of each target point, based on the projected distance of the scanning range of all target points in the previous scan cycle onto the radar plane and the corresponding horizontal angle of each target point. Then, based on the projected distance of the scanning range of all target points in the previous scan cycle onto the radar plane, and the corresponding horizontal angle of each target point, the x-coordinate and y-coordinate of each target point in the millimeter-wave radar coordinate system are determined. This millimeter-wave radar coordinate system is a rectangular coordinate system with the geometric center of the millimeter-wave radar as the origin, the X-axis pointing forward, the Y-axis pointing to the left, and the Z-axis pointing upward, satisfying the right-hand rule. The height of each target point is the coordinate in the Z-axis direction, and the x-coordinate and y-coordinate can be the coordinates in the X-axis and Y-axis directions, respectively.

[0107] Step S224: Based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, determine the included angle of each pair of target points in the previous scanning cycle.

[0108] The above method, which determines the included angle of each target point pair in the previous scanning cycle based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, can be based on the coordinates of each target point in the previous scanning cycle to determine the distance of each target point pair in the previous scanning cycle. The distance of a target point pair is the distance between the two target points determined by the target point pair. Based on the distance of each target point pair in the previous scanning cycle and the scanning distance of all target points, the included angle of each target point pair in the previous scanning cycle is determined according to the formula for calculating the sides and angles of a triangle.

[0109] Steps S222 to S224 above determine the coordinates of each target point in the previous scanning cycle, and based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, determine the included angle of each target point pair in the previous scanning cycle. By determining the included angle of each target point pair in the previous scanning cycle, it is convenient to adjust the periodic scanning point number of the millimeter-wave radar in the subsequent scan to obtain the periodic scanning point number of the current scanning cycle.

[0110] In another embodiment, step S222, based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point, determines the coordinates of each target point in the previous scanning cycle, including:

[0111] Step S2222: Based on the scanning distance of all target points in the previous scanning cycle and the elevation angle of the millimeter-wave radar, determine the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, as well as the height of each target point; the height of the target point is the vertical distance from the target point to the radar plane; the radar plane is the electromagnetic wave emission plane determined in the millimeter-wave radar coordinate system when the rotation axis of the millimeter-wave radar transmission center is perpendicular to the horizontal plane.

[0112] Figure 3 This diagram illustrates the relationship between the scanning range of a target point and the elevation angle of a millimeter-wave radar, as provided in an embodiment of this application. Figure 3 As shown, the projected distance D of the target point's scanning range on the radar plane, the target point's scanning range, and the target point's height form a right triangle. The millimeter-wave radar's elevation angle is PA, the target point's scanning range is EstRange, and the target point's height is z.

[0113] In this step, the calculation process for determining the projected distance D of the scanning distance of all target points in the previous scanning cycle onto the radar plane, based on the scanning distance of all target points in the previous scanning cycle and the elevation angle of the millimeter-wave radar, is as follows:

[0114] ;

[0115] Where EstRange is the scanning range of the target point, and PA is the elevation angle of the millimeter-wave radar.

[0116] The process of calculating the height z of the target point is as follows:

[0117] ;

[0118] Step S2224: Based on the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, and the horizontal angle corresponding to each target point, determine the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system in the previous scanning cycle.

[0119] The process of determining the x-coordinate of each target point in the millimeter-wave radar coordinate system in the previous scanning cycle, based on the projected distance of all target points in the previous scanning cycle onto the radar plane and the corresponding horizontal angle of each target point, is as follows:

[0120] ;

[0121] The above HA is the horizontal angle corresponding to the target point.

[0122] The process of determining the ordinate y of each target point in the millimeter-wave radar coordinate system during the previous scan cycle is as follows:

[0123] ;

[0124] Step S2226: Based on the height of each target point in the previous scanning cycle, and the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system, determine the coordinates of each target point in the previous scanning cycle.

[0125] Steps S2222 to S2226 above determine the coordinates of each target point in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point. By determining the coordinates of each target point, it is convenient to determine the included angle of each target point pair in the previous scanning cycle based on the coordinates of each target point.

[0126] Further, in one embodiment, step S224, determining the included angle between pairs of target points in the previous scanning cycle based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, includes:

[0127] Step S2242: Based on the coordinates of each target point in the previous scanning cycle, determine the distance between each target point pair in the previous scanning cycle; the distance between the target point pairs is the distance between the two target points determined by the target point pair.

[0128] The above-mentioned determination of the distance between each target point pair in the previous scanning cycle based on the coordinates of each target point in the previous scanning cycle can be: determining the coordinates of each target point in the previous scanning cycle, determining the coordinates of each target point in each target point pair in the previous scanning cycle, or determining the distance between each target point pair in the previous scanning cycle based on the coordinates of each target point in each target point pair in the previous scanning cycle.

[0129] Step S2244: Based on the distances of each target point pair in the previous scanning cycle and the scanning distances of all target points, determine the included angles of each target point pair in the previous scanning cycle.

[0130] The above method of determining the included angle of each target point pair in the previous scanning cycle based on the distances of each target point pair in the previous scanning cycle and the scanning distances of all target points can be based on determining the side lengths of the three sides of the triangle determined by the two target points corresponding to the target point pair and the position of the millimeter-wave radar. Then, based on the cosine theorem of the triangle, the included angle of each target point pair in the previous scanning cycle can be calculated.

[0131] Steps S2242 to S2244 above determine the distances of each target point pair in the previous scanning cycle. Then, based on the distances of each target point pair in the previous scanning cycle and the scanning distances of all target points, the included angles of each target point pair in the previous scanning cycle are determined. By determining the included angles of each target point pair in the previous scanning cycle, it is easier to adjust the periodic scanning point number of the millimeter-wave radar to obtain the periodic scanning point number of the current scanning cycle.

[0132] In one embodiment, step S230, based on the included angles of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, adjusts the number of periodic scanning points of the millimeter-wave radar to obtain the number of periodic scanning points in the current scanning cycle, including:

[0133] Step S232: Based on the angles between each pair of target points in the previous scanning cycle, determine the average value of the angles between each pair of target points in the previous scanning cycle.

[0134] Step S234: Based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, adjust the number of periodic scanning points of the millimeter-wave radar to obtain the number of periodic scanning points in the current scanning cycle.

[0135] The above method adjusts the number of periodic scan points of the millimeter-wave radar based on the difference between the average angle of each target point pair in the previous scan cycle and the beamwidth of the millimeter-wave radar antenna, thus obtaining the number of periodic scan points for the current scan cycle. Alternatively, if the average angle of each target point pair in the previous scan cycle is greater than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan point count of the millimeter-wave radar is increased based on the difference between the average angle of each target point pair in the previous scan cycle and the beamwidth of the millimeter-wave radar antenna, thus obtaining the number of scans for the current scan cycle. The number of periodic scan points is determined by the following: When the average angle between all target point pairs in the previous scan cycle is less than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan point count of the millimeter-wave radar is reduced based on the difference between the average angle between all target point pairs in the previous scan cycle and the beamwidth of the millimeter-wave radar antenna. When the average angle between all target point pairs in the previous scan cycle is equal to the beamwidth of the millimeter-wave radar antenna, there is no need to adjust the number of periodic scan points of the millimeter-wave radar.

[0136] To avoid excessively high frequency adjustments to the periodic scan point count of the millimeter-wave radar, a preset difference threshold can be set. When the average angle between all target point pairs in the previous scan cycle is greater than the beamwidth of the millimeter-wave radar antenna, and the absolute value of the difference between the average angle between all target point pairs in the previous scan cycle and the beamwidth of the millimeter-wave radar antenna is greater than the preset difference threshold, the scan count in the periodic scan point count of the millimeter-wave radar is increased based on the difference between the average angle between all target point pairs in the previous scan cycle and the beamwidth of the millimeter-wave radar antenna. This results in the current periodic scan point count. When the average angle between each pair of target points is less than the beamwidth of the millimeter-wave radar antenna, and the absolute value of the difference between the average angle between each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna is greater than a preset difference threshold, the number of scans in the periodic scan points of the millimeter-wave radar is reduced based on the difference between the average angle between each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna to obtain the number of periodic scan points in the current scanning cycle. When the average angle between each pair of target points in the previous scanning cycle is equal to the beamwidth of the millimeter-wave radar antenna, there is no need to adjust the number of periodic scan points of the millimeter-wave radar.

[0137] In another embodiment, initial values ​​can be assigned to the upscan frequency count and downscan frequency count, and the included angles of each target point pair in the previous scan cycle can be traversed. When the included angle of the target point pair in the scan cycle is greater than the beamwidth of the millimeter-wave radar antenna, the downscan frequency count is incremented by 1. When the included angle of the target point pair in the scan cycle is less than the beamwidth of the millimeter-wave radar antenna, the upscan frequency count is incremented by 1. Finally, after the previous scan cycle is completed, based on the magnitude of the upscan frequency count and downscan frequency count, it is determined whether to increase or decrease the number of scans in the periodic scan points of the millimeter-wave radar. The above-mentioned determination of whether to increase or decrease the number of scans in the periodic scan points of the millimeter-wave radar based on the magnitude of the up-scan frequency count and the down-scan frequency count can be as follows: when the up-scan frequency count is greater than the down-scan frequency count, the number of scans in the periodic scan points of the millimeter-wave radar is increased according to a preset up-scan point count rule; when the up-scan frequency count is less than the down-scan frequency count, the number of scans in the periodic scan points of the millimeter-wave radar is decreased according to a preset down-scan point count rule. The preset up-scan point count rule can be specifically set according to specific needs, and this embodiment does not impose specific limitations on it. For example, the preset up-scan point count rule can be to directly increase a certain number of scans, or to directly increase the number of scans in the periodic scan points by a certain multiple. Similarly, the preset down-scan point count rule can be specifically set according to specific needs, and this embodiment does not impose specific limitations on it. For example, the preset down-scan point count rule can be to directly decrease a certain number of scans, or to directly decrease the number of scans in the periodic scan points by a certain multiple.

[0138] Preferably, different pitch angles can be adjusted, and the number of periodic scan points corresponding to each pitch angle can be recorded. The recorded number of periodic scan points corresponding to each pitch angle can be used as the number of points for one scan at each subsequent pitch angle. A fixed update time can also be set, and the process of automatically adjusting the number of periodic scan points of the millimeter-wave radar at fixed update intervals can be repeated, and the number of periodic scan points of the millimeter-wave radar can be updated adaptively at regular intervals according to the state of the material being measured.

[0139] Steps S232 to S234 above determine the average angle of each target point pair in the previous scanning cycle, and adjust the number of periodic scanning points of the millimeter-wave radar based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, thus obtaining the number of periodic scanning points in the current scanning cycle. This adjustment of the number of periodic scanning points is made by considering the relationship between the angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar transmitting antenna, making the adjusted number of periodic scanning points suitable for the current elevation angle. This achieves automatic adjustment of the number of scanning points for the scanning area, solving the problems of high overlap rate of adjacent sampling points or poor edge imaging effect caused by excessive distance between adjacent sampling points in the prior art.

[0140] In one embodiment, step S234, based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, adjusts the periodic scanning point number of the millimeter-wave radar to obtain the periodic scanning point number of the current scanning cycle, including:

[0141] Step S2342: When the average angle of each target point pair in the previous scanning cycle is greater than the beamwidth of the millimeter-wave radar antenna, the number of periodic scanning points of the millimeter-wave radar is increased based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of periodic scanning points of the current scanning cycle.

[0142] The specific calculation process for increasing the number of periodic scan points of the millimeter-wave radar when the average angle between each pair of target points in the previous scanning cycle is greater than the beamwidth of the millimeter-wave radar antenna can be as follows:

[0143] ;

[0144] Where α is the increase in the number of periodic scan points of the millimeter-wave radar, A is the average angle between each pair of target points in the previous scan cycle, B is the beamwidth of the millimeter-wave radar antenna, and β is the number of periodic scan points of the millimeter-wave radar in the previous scan cycle.

[0145] The number of scan points in the current scan cycle is equal to the increase in the number of scan points in the millimeter-wave radar cycle and the sum of the number of scan points in the previous scan cycle of the millimeter-wave radar cycle.

[0146] Step S2344: When the average angle of each target point pair in the previous scanning cycle is less than the beamwidth of the millimeter-wave radar antenna, the number of periodic scanning points of the millimeter-wave radar is reduced based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of periodic scanning points of the current scanning cycle.

[0147] When the average angle between each pair of target points in the previous scanning cycle is less than the beamwidth of the millimeter-wave radar antenna, the specific calculation process for reducing the number of periodic scan points of the millimeter-wave radar based on the difference between the average angle between each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna to obtain the number of periodic scan points of the current scanning cycle can be as follows:

[0148] ;

[0149] Where α1 is the reduction in the number of periodic scan points of the millimeter-wave radar.

[0150] The number of periodic scan points in the current scanning cycle is equal to the difference between the number of periodic scan points in the previous scanning cycle of the millimeter-wave radar and the amount by which the number of periodic scan points of the millimeter-wave radar is reduced.

[0151] Steps S2342 to S2344 above adjust the number of periodic scan points of the millimeter-wave radar based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, thus obtaining the number of periodic scan points for the current scanning cycle. This adjustment of the number of periodic scan points is based on the relationship between the angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar transmitting antenna, making the adjusted number of periodic scan points suitable for the current elevation angle. This achieves automatic adjustment of the number of scan points for the scanning area, solving the problems of high overlap rate of adjacent sampling points or poor edge imaging effect caused by excessive distance between adjacent sampling points in the prior art.

[0152] The present embodiment will now be described and illustrated through preferred embodiments.

[0153] Figure 4 This is a flowchart of a preferred embodiment of the adaptive adjustment method for the number of scan points provided in this application. Figure 4 As shown, the adaptive adjustment method for the number of scan points includes the following steps:

[0154] Step S401: Obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process.

[0155] Step S402: Based on the scanning distance of all target points in the previous scanning cycle and the elevation angle of the millimeter-wave radar, determine the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, as well as the height of each target point; the height of the target point is the vertical distance from the target point to the radar plane; the radar plane is the electromagnetic wave emission plane determined in the millimeter-wave radar coordinate system when the rotation axis of the millimeter-wave radar transmission center is perpendicular to the horizontal plane.

[0156] Step S403: Based on the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, and the horizontal angle corresponding to each target point, determine the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system in the previous scanning cycle.

[0157] Step S404: Based on the height of each target point in the previous scanning cycle, and the abscissa and ordinate of each target point in the millimeter-wave radar coordinate system, determine the coordinates of each target point in the previous scanning cycle.

[0158] Step S405: Based on the coordinates of each target point in the previous scanning cycle, determine the distance between each pair of target points in the previous scanning cycle; the distance between the target point pairs is the distance between the two target points determined by the target point pairs; the target point pairs are the point pairs determined by pairing up target points that are adjacent in the scanning sequence.

[0159] Step S406: Based on the distances of each target point pair in the previous scanning cycle and the scanning distances of all target points, determine the included angles of each target point pair in the previous scanning cycle; the included angles of the target point pairs are the angle differences between the two sampling directions corresponding to the target point pairs.

[0160] Step S407: Based on the angles between each pair of target points in the previous scanning cycle, determine the average value of the angles between each pair of target points in the previous scanning cycle.

[0161] Step S408: Based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, adjust the number of scanning points of the millimeter-wave radar to obtain the number of scanning points in the current scanning cycle.

[0162] Steps S401 to S408 above involve obtaining the scanning distances of all target points in the previous scanning cycle. Then, based on the scanning distances of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, the included angles of each pair of target points in the previous scanning cycle are determined. Based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the number of scanning points of the millimeter-wave radar is updated to obtain the periodic scanning point number of the current scanning cycle. By adjusting the periodic scanning point number according to the relationship between the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the adjusted periodic scanning point number is suitable for the current elevation angle. This achieves automatic adjustment of the number of scanning points for the scanning surface, solving the problems of high overlap rate of adjacent sampling points or poor edge imaging effect caused by excessive distance between adjacent sampling points in the prior art.

[0163] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0164] Based on the same inventive concept, this embodiment also provides a scanning point adaptive adjustment device, which is used to implement the above embodiments and preferred embodiments, and will not be repeated as described above. The terms "module," "unit," "subunit," etc., used below can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0165] In one embodiment, Figure 5 This is a structural block diagram of a scanning point number adaptive adjustment device provided in an embodiment of this application, as shown below. Figure 5 As shown, this adaptive adjustment device for the number of scanning points, applied to the scanning system of millimeter-wave radar, includes:

[0166] The distance determination module 52 is used to obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process;

[0167] The included angle determination module 54 is used to determine the included angle of each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar; the target point pair is a pair of points determined by pairing up target points that are adjacent in the scanning sequence; the included angle of the target point pair is the angle difference between the two sampling directions corresponding to the target point pair.

[0168] And adjustment module 56, used to adjust the number of periodic scan points of millimeter-wave radar based on the included angle of each target point pair in the previous scan cycle and the beamwidth of the transmitting antenna of millimeter-wave radar, to obtain the number of periodic scan points in the current scan cycle; the number of periodic scan points is the number of scan points of millimeter-wave radar in one scan cycle.

[0169] The aforementioned adaptive adjustment device for the number of scanning points obtains the scanning distances of all target points in the previous scanning cycle. Then, based on the scanning distances of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, it determines the included angles of each pair of target points in the previous scanning cycle. Based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, it updates the periodic scanning point count of the millimeter-wave radar to obtain the periodic scanning point count for the current scanning cycle. By adjusting the periodic scanning point count according to the relationship between the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar's transmitting antenna, the adjusted periodic scanning point count is suitable for the current elevation angle. This achieves automatic adjustment of the number of scanning points on the scanning surface, solving the problems of high overlap rates between adjacent sampling points or poor edge imaging effects caused by excessive distances between adjacent sampling points in existing technologies.

[0170] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0171] In one embodiment, a millimeter-wave radar scanning system is provided, the system including a gimbal, a millimeter-wave radar and a main control module;

[0172] The gimbal, connected to the main control module, is used to rotate in response to received control commands;

[0173] The millimeter-wave radar is connected to the main control module and fixed on the gimbal, rotating as the gimbal rotates.

[0174] The main control module is used to control the operation of the gimbal and millimeter-wave radar according to the scanning point number adaptive adjustment method of any embodiment of this application.

[0175] In this embodiment, the gimbal rotates horizontally by 360°, allowing the millimeter-wave radar to acquire the position of the target point for one scanning cycle. The main control module controls the gimbal rotation and, based on the received target reflected echo signals, determines the scanning distance of all target points within the scanning cycle. Based on the scanning distances of all target points within the scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, it determines the included angle between each pair of target points within the scanning cycle. Based on the included angle between each pair of target points within the scanning cycle and the beamwidth of the millimeter-wave radar antenna, it updates the number of periodic scanning points of the millimeter-wave radar, obtaining the updated number of periodic scanning points. Based on the updated number of periodic scanning points, it determines the transmission frequency of the millimeter-wave radar and sends the transmission frequency to the millimeter-wave radar.

[0176] In one embodiment, variable-speed scanning adjustment can be implemented to reduce redundant points and improve processing speed and 3D imaging quality. Within the same scanning time, the number of scanning points is reduced for the inner circle with a smaller radius, and increased for the outer circle with a larger radius. By calculating the distance between two adjacent points, and then calculating the angle between them, the density of sampling points within the same circle is determined by comparing the angle with the antenna beamwidth, and the information at the current elevation angle is adjusted accordingly.

[0177] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0178] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0179] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for adaptive adjustment of the number of scanning points, applied to a scanning system of millimeter-wave radar, characterized in that, The method includes: Obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process; Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, the included angle of each target point pair in the previous scanning cycle is determined; the target point pair is a pair of points determined by pairing adjacent target points in the scanning sequence; the included angle of the target point pair is the angle difference between the two sampling directions corresponding to the target point pair; Based on the included angles of each target point pair in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, the number of periodic scanning points of the millimeter-wave radar is adjusted to obtain the number of periodic scanning points in the current scanning cycle; the number of periodic scanning points is the number of scanning points of the millimeter-wave radar in one scanning cycle.

2. The adaptive adjustment method for the number of scan points according to claim 1, characterized in that, The step of obtaining the scanning distance of all target points in the previous scanning cycle includes: The millimeter-wave radar performs a first Fourier transform on the target reflection echo signals received from each target point in the previous scanning cycle to obtain the first Fourier transform signal corresponding to each target point; the target reflection echo signal is the signal returned after reflection at the target point by the electromagnetic wave emitted by the millimeter-wave radar during the scanning process. Determine the maximum modulus value in the signal after the first Fourier transform corresponding to each target point, and use it as the first modulus value corresponding to each target point; After performing an inverse Fourier transform on the received target reflected echo signals from each of the target points, downsampling is performed to obtain the downsampled signals corresponding to each of the target points; A second Fourier transform is performed on the downsampled signal corresponding to each of the target points to obtain the signal after the second Fourier transform corresponding to each of the target points; Determine the maximum modulus value in the signal after the second Fourier transform corresponding to each target point, and use it as the second modulus value corresponding to each target point; Based on the first modulus value corresponding to each target point, the second modulus value corresponding to each target point, the preset distance resolution, and the resolution enhancement factor, the scanning distance of all target points in the previous scanning cycle is determined.

3. The adaptive adjustment method for the number of scan points according to claim 2, characterized in that, Before performing a first Fourier transform on the target reflected echo signals received by the millimeter-wave radar from each target point in the previous scanning cycle to obtain the first Fourier transformed signals corresponding to each target point, the process includes: The received target reflected echo signals from each of the target points are windowed to obtain the windowed signals corresponding to each of the target points; The windowed signal corresponding to each target point is subjected to complex modulation to obtain the complex modulated signal corresponding to each target point.

4. The adaptive adjustment method for the number of scan points according to claim 3, characterized in that, Before performing inverse Fourier transform on the received target reflected echo signals from each of the target points and then downsampling them to obtain the downsampled signals corresponding to each of the target points, the process includes: The spectrum of the signal after the first Fourier transform corresponding to each target point is shifted to obtain the spectrum-shifted signal corresponding to each target point. The spectrum-shifted signals corresponding to each target point are subjected to low-pass filtering to obtain the low-pass filtered signals corresponding to each target point.

5. The adaptive adjustment method for the number of scan points according to claim 1, characterized in that, The determination of the included angle between each pair of target points in the previous scanning cycle, based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar, includes: Based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point, the coordinates of each target point in the previous scanning cycle are determined. Based on the coordinates of each target point in the previous scanning cycle and the scanning distance of all target points, the included angle of each pair of target points in the previous scanning cycle is determined.

6. The adaptive adjustment method for the number of scan points according to claim 5, characterized in that, The determination of the coordinates of each target point in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, and the horizontal angle corresponding to each target point includes: Based on the scanning distances of all target points in the previous scanning cycle and the elevation angle of the millimeter-wave radar, the projected distances of the scanning distances of all target points in the previous scanning cycle onto the radar plane, and the height of each target point are determined; the height of the target point is the vertical distance from the target point to the radar plane; the radar plane is the electromagnetic wave emission plane determined in the millimeter-wave radar coordinate system when the rotation axis of the millimeter-wave radar transmission center is perpendicular to the horizontal plane; Based on the projected distance of the scanning distance of all target points in the previous scanning cycle onto the radar plane, and the horizontal angle corresponding to each target point, the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system in the previous scanning cycle are determined. Based on the height of each target point in the previous scanning cycle, and the horizontal and vertical coordinates of each target point in the millimeter-wave radar coordinate system, the coordinates of each target point in the previous scanning cycle are determined.

7. The adaptive adjustment method for the number of scan points according to claim 5, characterized in that, Determining the included angle between pairs of target points within the previous scanning cycle based on the coordinates of each target point within the previous scanning cycle and the scanning distance of all target points includes: Based on the coordinates of each target point in the previous scanning cycle, the distance between each pair of target points in the previous scanning cycle is determined; the distance between the two target points determined by the pair of target points is the distance between the two target points. Based on the distances between each pair of target points in the previous scanning cycle and the scanning distances of all target points, the included angles between each pair of target points in the previous scanning cycle are determined.

8. The adaptive adjustment method for the number of scan points according to claim 1, characterized in that, The step of adjusting the number of periodic scan points of the millimeter-wave radar based on the included angles of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar to obtain the number of periodic scan points in the current scanning cycle includes: Based on the included angle of each pair of target points in the previous scanning cycle, determine the average value of the included angle of each pair of target points in the previous scanning cycle; Based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, the number of periodic scanning points of the millimeter-wave radar is adjusted to obtain the number of periodic scanning points in the current scanning cycle.

9. The adaptive adjustment method for the number of scan points according to claim 8, characterized in that, The step of adjusting the periodic scan point number of the millimeter-wave radar based on the difference between the average angle of each pair of target points in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna to obtain the periodic scan point number of the current scanning cycle includes: When the average angle of each target point pair in the previous scanning cycle is greater than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan points of the millimeter-wave radar is increased based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of scan points in the current scanning cycle. When the average angle of each target point pair in the previous scanning cycle is less than the beamwidth of the millimeter-wave radar antenna, the number of scans in the periodic scan points of the millimeter-wave radar is reduced based on the difference between the average angle of each target point pair in the previous scanning cycle and the beamwidth of the millimeter-wave radar antenna, so as to obtain the number of periodic scan points in the current scanning cycle.

10. A scanning point number adaptive adjustment device, applied to the scanning system of millimeter-wave radar, characterized in that, The device includes: The distance determination module is used to obtain the scanning distance of all target points in the previous scanning cycle; the scanning distance is the distance from the millimeter-wave radar to the target point; the target point is the point where the electromagnetic wave emitted by the millimeter-wave radar intersects with and is reflected from the surface of the target object during the scanning process; Angle determination module is used to determine the angle between each pair of target points in the previous scanning cycle based on the scanning distance of all target points in the previous scanning cycle, the elevation angle of the millimeter-wave radar, the horizontal angle corresponding to each target point, and the position of the millimeter-wave radar; the target point pair is a pair of points determined by pairing adjacent target points in the scanning sequence; the angle between the target point pairs is the angle difference between the two sampling directions corresponding to the target point pair; And an adjustment module, used to adjust the number of periodic scan points of the millimeter-wave radar based on the included angle of each pair of target points in the previous scanning cycle and the beamwidth of the transmitting antenna of the millimeter-wave radar, to obtain the number of periodic scan points in the current scanning cycle; the number of periodic scan points is the number of scan points of the millimeter-wave radar in one scanning cycle.

11. A scanning system for millimeter-wave radar, characterized in that, The system includes a gimbal, a millimeter-wave radar, and a main control module; The gimbal is connected to the main control module and is used to rotate in response to received control commands; The millimeter-wave radar is connected to the main control module and fixed on the gimbal, rotating as the gimbal rotates. The main control module is used to control the gimbal and the millimeter-wave radar to operate using the adaptive adjustment method for the number of scanning points according to any one of claims 1-9.

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