WO2022002004A1 - 一种分布式微波雷达的成像方法及装置 - Google Patents

一种分布式微波雷达的成像方法及装置 Download PDF

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WO2022002004A1
WO2022002004A1 PCT/CN2021/102923 CN2021102923W WO2022002004A1 WO 2022002004 A1 WO2022002004 A1 WO 2022002004A1 CN 2021102923 W CN2021102923 W CN 2021102923W WO 2022002004 A1 WO2022002004 A1 WO 2022002004A1
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radar
imaging
detection target
microwave radar
target
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PCT/CN2021/102923
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English (en)
French (fr)
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景国彬
胡滨
杨敬
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华为技术有限公司
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Priority to EP21832776.5A priority Critical patent/EP4166984A4/en
Publication of WO2022002004A1 publication Critical patent/WO2022002004A1/zh
Priority to US18/147,528 priority patent/US20230152442A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9004—SAR image acquisition techniques
    • G01S13/9011—SAR image acquisition techniques with frequency domain processing of the SAR signals in azimuth
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/91—Radar or analogous systems specially adapted for specific applications for traffic control
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/35—Details of non-pulse systems
    • G01S7/352—Receivers
    • G01S7/354—Extracting wanted echo-signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/411—Identification of targets based on measurements of radar reflectivity
    • G01S7/412—Identification of targets based on measurements of radar reflectivity based on a comparison between measured values and known or stored values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/415—Identification of targets based on measurements of movement associated with the target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/418—Theoretical aspects

Definitions

  • the present application relates to the field of radar signal processing, and in particular, to an imaging method and device for distributed microwave radar.
  • Microwave radar is a radar working in the microwave band detection, usually refers to the 100M-200GHz frequency domain, the working range of microwave radar: 1mm-1m, divided into millimeter wave, centimeter wave and decimeter wave. Its working principle is to transmit a microwave detection signal to the target object, and then compare the received signal reflected from the target object with the transmitted detection signal. After the signal is processed, the relevant information of the target object, such as target distance, azimuth, and speed, is obtained. , posture, shape, structure, size and other parameters.
  • millimeter wave radar refers to the radar working in the millimeter wave band.
  • millimeter waves refer to electromagnetic waves in the frequency domain of 30 to 300 GHz (wavelength is 1 to 10 mm).
  • the wavelength of millimeter waves is between centimeter waves and light waves. Therefore, millimeter waves have the advantages of both microwave guidance and photoelectric guidance.
  • Millimeter waves are widely used in 5G communications, satellite remote sensing, missile guidance, electronic countermeasures and other fields.
  • related technologies such as circuit design and antenna technology have been increasingly developed and matured. Millimeter wave radar Its applications in the field of road detection and automatic driving have also achieved great development.
  • millimeter-wave radar is mainly used for ranging or speed measurement of single-point targets, and high-resolution two-dimensional imaging has not yet been achieved.
  • Synthetic Aperture Radar SAR
  • Conventional radar imaging algorithms include: Range Doppler Algorithm (RDA), Range Migration Algorithm ( Range Migration Algorithm, RMA), back projection algorithm (Back Projection Algorithm, BPA) and frequency scaling algorithm (Frequency Scaling Algorithm, FSA) and so on.
  • the above algorithm cannot overcome the inherent echo aliasing problem of SAR radar in the application of side-view perception imaging, so there is an imaging blind spot for the observation target.
  • the problem of echo aliasing that is, the position of the target sampling point that is highly symmetrical to the radar, because the time delay to the radar is the same, falls into the same sampling unit, resulting in aliasing. Therefore, the imaging resolution of the observation target is low.
  • the present application provides an imaging method and device for a distributed microwave radar.
  • an embodiment of the present application provides a distributed microwave radar imaging method, the method includes: acquiring a first echo signal received by a first microwave radar, the first microwave radar is set at a first height; acquiring a second echo signal The second echo signal received by the microwave radar, the second microwave radar is set at a second height, wherein the first height is lower than the second height; the first echo signal of the detection target is determined based on the first echo signal a radar imaging result image; a second radar imaging result image of the detection target is determined based on the second echo signal; the first radar imaging result image and the second radar imaging result image are fused to obtain a target fusion image.
  • the distributed microwave radar imaging realizes the complementary characteristics of high and low viewing angles, not only the length information of the detection target can be measured, but also the problem of inconsistent resolution in the height dimension of the detection target is solved, and the overall high resolution of the detection target is realized. rate imaging.
  • the determining the first radar imaging result image of the detection target based on the first echo signal includes: determining the first radar imaging initial image of the detection target based on the first echo signal performing a first geometric deformation correction on the first radar imaging initial image to obtain a first radar imaging result image; the determining the second radar imaging result image of the detection target based on the second echo signal includes: based on the The second echo signal determines a second radar imaging initial image of the detection target; and performing a second geometric deformation correction on the second radar imaging initial image to obtain a second radar imaging result image.
  • the first geometric deformation correction includes: based on the height of the first microwave radar and the shortest distance between the first microwave radar and the detection target, determining the difference between the first imaging width and the height of the detection target The first change relationship between the two is a nonlinear functional relationship; based on the first change relationship, interpolation processing is performed to determine the first radar imaging result image; wherein, the first imaging frame of the detection target is The width is the distance from the first microwave radar to the detection target vertex minus the shortest distance; the second geometric deformation correction includes: based on the height of the second microwave radar, the distance between the second microwave radar and the detection target The shortest distance is to determine the second variation relationship between the imaging width and height of the detection target, and the second variation relationship is a nonlinear functional relationship; based on the second variation relationship, interpolation processing is performed to determine the second radar imaging result image; wherein, the second imaging width of the detection target is the distance from the second microwave radar to the bottom point of the detection target minus the shortest distance.
  • the ratio between the height of the detection target and the range of microwave radar is relatively large, and the nonlinear transformation in the slant range projection is adopted, which is more accurate and more accurate than the traditional linear stretching scheme in the remote sensing field. Describes the oblique projection result of the detection target, thus improving the imaging resolution of the detection target.
  • fusing the first radar imaging result image and the second radar imaging result image to obtain a target fusion image includes: merging an upper part of the imaging area corresponding to the detection target in the first radar imaging result image Perform splicing and fusion with the lower part of the imaging area corresponding to the detection target in the second imaging result image to obtain a target fusion image.
  • the lower boundary of the upper part of the imaging region and the upper boundary of the lower part of the imaging region correspond to the reference line of the detection target.
  • the high-resolution parts of the two radar imaging results are selected for fusion, which overcomes the problem of inconsistent resolution in the height dimension, thereby improving the image quality.
  • Overall imaging resolution by splicing and merging the high- and low-angle radar imaging results images, the high-resolution parts of the two radar imaging results are selected for fusion, which overcomes the problem of inconsistent resolution in the height dimension, thereby improving the image quality. Overall imaging resolution.
  • the method further includes: determining the shape information or structure of the detection target based on the target fusion image information.
  • the shape information includes a two-dimensional size or a three-dimensional three-dimensional size of the detection target.
  • the shape information or structure information of the detection target is determined based on the target fusion image, so as to obtain accurate target feature information, improve the imaging resolution, and facilitate subsequent further processing of the detection target.
  • an embodiment of the present application provides a distributed microwave radar imaging device, including: a first acquisition unit that acquires a first echo signal received by a first microwave radar, where the first microwave radar is set at a first height; The second acquisition unit acquires the second echo signal received by the second microwave radar, the second microwave radar is set at a second height, wherein the first height is lower than the second height; the first imaging unit, The first radar imaging result image of the detected target is determined based on the first echo signal; the second imaging unit is used to determine the second radar imaging result image of the detected target based on the second echo signal; the target fusion unit is used to combine The first radar imaging result image and the second radar imaging result image are fused to obtain a target fusion image.
  • the first imaging unit is specifically configured to: determine a first radar imaging initial image of the detection target based on the first echo signal; perform a first radar imaging initial image on the first radar imaging initial image A first radar imaging result image is obtained by correcting geometric deformation; the second imaging unit is specifically configured to: determine a second radar imaging initial image of the detection target based on the second echo signal; and form the second radar imaging initial image The second geometric deformation correction is performed to obtain a second radar imaging result image.
  • the first geometric deformation correction includes: based on the height of the first microwave radar and the shortest distance between the first microwave radar and the detection target, determining the difference between the first imaging width and the height of the detection target The first change relationship between the two is a nonlinear functional relationship; based on the first change relationship, interpolation processing is performed to determine the first radar imaging result image; wherein, the first imaging frame of the detection target is The width is the distance from the first microwave radar to the detection target vertex minus the shortest distance; the second geometric deformation correction includes: based on the height of the second microwave radar, the distance between the second microwave radar and the detection target The shortest distance is to determine the second variation relationship between the imaging width and height of the detection target, and the second variation relationship is a nonlinear functional relationship; based on the second variation relationship, interpolation processing is performed to determine the second radar imaging result image; wherein, the second imaging width of the detection target is the distance from the second microwave radar to the bottom point of the detection target minus the shortest distance.
  • the target fusion unit is specifically configured to: combine the upper part of the imaging area corresponding to the detection target in the first radar imaging correction image with the lower part of the imaging area corresponding to the detection target in the second imaging correction image Perform splicing and fusion to obtain the target fusion image.
  • the lower boundary of the upper part of the imaging region and the upper boundary of the lower part of the imaging region correspond to the reference line of the detection target.
  • a target shape determination unit is further included, and the target shape determination unit is specifically configured to: determine the shape information or structure information of the detection target based on the target fusion image.
  • the shape information includes a two-dimensional size or a three-dimensional three-dimensional size of the detection target.
  • an embodiment of the present application provides a distributed microwave radar imaging system, including a first microwave radar, a second microwave radar, and the device according to any one of the second aspects.
  • an embodiment of the present application provides a roadside microwave radar imaging system, including a first microwave radar, a second microwave radar, and the device according to any one of the second aspect, wherein the first microwave radar, the first microwave radar Two microwave radars are arranged on the roadside, and the detection target is a vehicle.
  • an embodiment of the present application provides a vehicle, including a first microwave radar, a second microwave radar, and the device according to any one of the second aspect, wherein the first microwave radar and the second microwave radar are arranged at the same on the above vehicle.
  • an embodiment of the present application provides a computer-readable storage medium, where the storage medium stores a computer program, and the computer program is used to execute the imaging method according to any one of the first aspect.
  • an embodiment of the present application provides a computer program product, which, when running on a computer, causes the computer to execute the imaging method described in any one of the above-mentioned first aspect.
  • an embodiment of the present application provides an electronic device, the electronic device comprising: a processor; a memory for storing instructions executable by the processor; the processor for executing any one of the first aspect The control method of the target object described in item.
  • an embodiment of the present application provides a chip, including at least one processor, where the processor is coupled to a memory, and the processor is configured to read instructions in the memory and execute any one of the first aspects according to the instructions the method described. It can be understood that any of the distributed microwave radar imaging devices, readable storage media, computer program products, imaging systems, vehicles, and electronic devices provided above can be implemented by the corresponding methods provided above. Therefore, for the beneficial effects that can be achieved, reference may be made to the beneficial effects in the corresponding methods provided above, which will not be repeated here.
  • FIG. 1 is a schematic diagram of an application scenario diagram provided by an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a microwave radar imaging system according to an embodiment of the present application.
  • FIG. 3 is a schematic flowchart of a distributed microwave radar imaging method according to an embodiment of the present application.
  • FIG. 4 is a schematic flowchart of a method for determining a first radar imaging result based on a first echo signal according to an embodiment of the present application
  • FIG. 5a is a schematic diagram of the actual size of a vehicle according to an embodiment of the application.
  • FIG. 5b is a schematic diagram of an initial imaging result of a first radar provided by an embodiment of the present application.
  • FIG. 5c is a schematic diagram of an initial imaging result of a second radar provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of an imaging width of a detection target by a first microwave radar provided by an embodiment of the present application
  • FIG. 7a is a schematic diagram of a first radar imaging result provided by an embodiment of the present application.
  • FIG. 7b is a schematic diagram of a second radar imaging result provided by an embodiment of the present application.
  • FIG. 8 is a schematic flowchart of a specific method for correcting a first geometric deformation provided by an embodiment of the present application
  • FIG. 9 is a schematic diagram of a variation curve of the imaging width and height of a detection target provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of an imaging width of a detection target by a second microwave radar provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of an outline dimension and direction of a detection target provided by an embodiment of the present application.
  • FIG. 12 is a three-dimensional geometric schematic diagram of a detection target provided by an embodiment of the present application.
  • FIG. 13 is a schematic structural diagram of a distributed microwave radar imaging device provided by an embodiment of the present application.
  • Synthetic Aperture Radar is a radar system that works in a pulsed manner. Its signal changes in different degrees along the range direction and along the azimuth direction. It changes rapidly along the range direction and slowly changes along the azimuth direction. .
  • the specific imaging mechanism of SAR perception imaging is as follows: in the azimuth direction, the chirp signal is continuously transmitted to the observation area to form a virtual long synthetic aperture array, that is, the synthetic aperture principle is used to form a high resolution imaging in the azimuth direction; Ultra-wideband chirp signal, and obtain high range resolution through pulse compression technology, so as to obtain two-dimensional high-resolution radar perception image.
  • the distance direction is the direction perpendicular to the movement of the detection target
  • the azimuth direction is the direction of the movement of the detection target.
  • Synthetic Aperture Radar is a kind of active microwave imaging with certain penetrability. It can capture more difficult-to-find target information in optical images all day, all day, and has a good reconnaissance effect.
  • Frequency Modulated Continuous Wave (FMCW) signal frequency is a function of time.
  • Two widely used FM forms are sawtooth FM and triangular FM.
  • the frequency of the transmitted signal varies linearly with time.
  • the sawtooth changes
  • the target echo is the replica wave of the transmitted waveform
  • the two-way echo delay ⁇ 2R/C, where R is the target distance and C is the speed of light.
  • R is the target distance
  • C the speed of light.
  • part of the beat frequency is positive and part is negative, and the part of the negative beat frequency in the frequency sweep period is very small, because the maximum echo delay usually set is also very small relative to the frequency sweep period .
  • FMCW SAR generally transmits a large time-width-bandwidth product chirp signal (and the transmitted signal occupies nearly the entire pulse repetition period) to achieve high resolution in the range direction.
  • the FMCW SAR generally adopts the dechirp reception method. This is because the frequency sweep period of the FMCW SAR reaches the millisecond level.
  • the direct sampling and receiving method the number of sampling points in the distance direction will reach several million points or even more. Such a large amount of data places high requirements on the data transmission rate and processing speed, resulting in an increase in the complexity of the system.
  • FMCW SAR is generally used as a miniaturized SAR
  • its range mapping bandwidth is usually narrow, so it is appropriate to use the Dechirp receiving method.
  • the sampling frequency of the system only needs to be larger than the difference frequency signal bandwidth corresponding to the scene mapping bandwidth. , so that the sampling rate can be greatly reduced, the number of sampling points is reduced, the system equipment is simplified, and it is more suitable for commercial applications.
  • the frequency scaling algorithm (Frequency Scaling Algorithm, FSA) is aimed at the received data of Dechirp under the FMCW system radar, and it directly processes the signal after the delineated tone.
  • FSA is to perform a variable scaling operation on the distance fast time in the range-Doppler domain to correct the spatial variability of the range migration.
  • the range migration of all scatter points in the scene is corrected to the reference distance, and then a unified reference function is used to carry out Correction for residual distance migration.
  • the entire algorithm only includes complex multiplication and FFT operations, and has been widely used in Dechirp data processing due to its high precision and small computational complexity. Therefore, the present application intends to use the frequency scaling algorithm for imaging processing.
  • FIG. 1 is a schematic diagram of an application scenario of an embodiment of the present application. As shown in FIG. 1 , the application scenario includes a first microwave radar 1 and a second microwave radar 2 , and the detection target is the vehicle in the figure.
  • the first microwave radar 1 and the second microwave radar 2 may be any one or more combinations of millimeter-wave radars, X-band radars, and C-band radars divided by frequency bands.
  • the first microwave radar 1 and the second microwave radar 2 may be the same type of radar, or may be different types of radars.
  • the millimeter-wave radar may be a millimeter-wave radar in frequency bands such as 24 GHz, 77 GHz, 79 GHz, and 94 GHz.
  • the first microwave radar 1 and the second microwave radar 2 may also be any one or more combinations of millimeter-wave radars of different bands, or may be millimeter-wave radars of the same band.
  • the distributed microwave radar imaging method of the embodiment of the present application can be applied to a roadside detection system, an unmanned driving system, or a driving assistance early warning system, and the like.
  • the roadside detection system can be used for roadside perception.
  • Roadside perception is the basis for data acquisition of intelligent transportation systems and other technologies, and provides a basis for high-speed toll inspection and urban road monitoring.
  • the required data includes: the length, height, and axle of the vehicle target number, speed and distance, surrounding road congestion status, etc.
  • the driver assistance warning system includes: automatic parking, line merge assistance, blind spot detection, etc.
  • the detection target may be a vehicle that passes the roadside detection system, including cars, trucks, trucks, and the like.
  • the detection target can be any target such as vehicles, people, trees, curbs, obstacles, etc.
  • FIG. 2 is a schematic structural diagram of a microwave radar imaging system provided by an embodiment of the present application, including a first microwave radar 1 , a second microwave radar 2 , and a distributed microwave radar imaging device 3 , wherein the distributed microwave radar imaging device 3 is respectively connected with the first microwave radar imaging device 3 .
  • the microwave radar 1 and the second microwave radar 2 are connected.
  • the distributed microwave radar imaging device 3 processes the radar echo data by using the distributed microwave radar imaging method of the embodiment of the present application, thereby imaging the detection target to determine target information, and the target information reflects the detection target. Dimension information, speed, position and other information.
  • the distributed microwave radar imaging method of the embodiment of the present application can improve the imaging resolution of the detected target, and the specific implementation can refer to the explanation of the following embodiments.
  • the distributed microwave radar imaging device 3 may include: an IO interface 111, a processor 112, and a memory 113 for storing executable instructions of the processor.
  • the IO interface 111 may include an input/output (I/O) interface.
  • the output device may be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector (projector), etc.
  • the input device may be a mouse, a keyboard, a touch screen device or a sensing device, and at least two imaging sensors, among others.
  • the processor 112 may be any conventional processor, such as a commercially available central processing unit (CPU). Alternatively, the processor may be a dedicated device such as application specific integrated circuits (ASIC) or other hardware-based processors.
  • FIG. 2 functionally illustrates a processor, memory, those of ordinary skill in the art will understand that the processor, radar imaging device, or memory may actually include multiplexes that may or may not be stored within the same physical enclosure processor, radar imaging device, or memory.
  • the memory may be a hard disk drive or other storage medium located within a housing other than the distributed microwave radar imaging device 3 . Accordingly, reference to a processor or radar imaging device will be understood to include reference to a collection of processors or computers or memories that may or may not operate in parallel. Rather than using a single processor to perform the steps described herein, some components such as the steering and deceleration components may each have their own processor that only performs computations related to component-specific functions .
  • a processor may be located remotely from the microwave radar and in wireless communication with the microwave radar. In other aspects, some of the processes described herein are performed on a processor disposed within a roadside base station or vehicle while others are performed by a remote processor, including taking the necessary steps to perform a single maneuver.
  • memory 113 may contain instructions 114 (eg, program logic) executable by processor 112 to perform various functions of distributed microwave radar imaging device 3, including those described above.
  • the memory 113 may also contain additional instructions, including instructions for one or more of the first microwave radar 1 or the second microwave radar 2 to transmit data, receive data from, interact with and/or control.
  • memory 113 may store data, such as images of detected objects, or, in vehicle mode, road maps, route information, vehicle location, direction, speed, and other such vehicle data, among other information. Such information may be used by the vehicle and computer systems during operation of the vehicle in autonomous, semi-autonomous and/or manual modes.
  • the above-mentioned distributed microwave radar imaging device 3 the first microwave radar 1 and the second microwave radar 2 may be installed on the same device, for example, a roadside sensing base station, a vehicle, and the like. Another achievable way is that the first microwave radar 1 and the second microwave radar 2 can be installed on different devices, such as different sensing base stations on the roadside, etc.
  • the distributed microwave radar imaging device 3 can be a terminal device. The apparatus may communicate with the equipment provided with the first microwave radar 1 and the second microwave radar 2 to obtain radar echo data.
  • the roadside sensing base station returns the echo data of the first microwave radar 1 and the second microwave radar 2 according to the air interface channel status, or the processed radar images or detection information such as target features to the charging and detection system to realize high-speed scene inspection. Toll collection and urban road monitoring functions.
  • the terminal device may be a fixed terminal or a mobile terminal.
  • the fixed terminal can be an industrial computer or the like.
  • a mobile terminal may also be referred to as user equipment, access terminal, subscriber unit, subscriber station, mobile station, mobile station, user terminal, terminal, wireless communication device, user agent, or user equipment.
  • the mobile terminal can be an in-vehicle device, a wearable device, a smart phone, a tablet computer, a personal digital processing device, a handheld device with wireless communication capabilities, or other processing device connected to a wireless modem, etc.
  • the terminal equipment can also be replaced by the control unit of the roadside base station or the vehicle control unit.
  • the radar imaging apparatus of this embodiment may be implemented by means of software and/or hardware.
  • the apparatus may use the above-mentioned terminal equipment or an internal chip of the terminal equipment.
  • the radar imaging method will be described below by taking the distributed microwave radar imaging device as the execution subject. As shown in Figure 3, the method may include the following steps:
  • the distributed microwave radar imaging device 3 controls the first microwave radar 1 and the second microwave radar 2 to start radar observation of the detection target until the detection target leaves the radar beam.
  • the first microwave radar 1 includes a first transmitter, which can be an antenna, and the distributed microwave radar imaging device 3 controls the antenna to emit a first detection electromagnetic wave to the detection target, and the first detection electromagnetic wave passes through the detection After the target is reflected, the antenna of the first microwave radar 1 receives the returned electromagnetic wave, that is, the first echo signal.
  • a first transmitter which can be an antenna
  • the distributed microwave radar imaging device 3 controls the antenna to emit a first detection electromagnetic wave to the detection target, and the first detection electromagnetic wave passes through the detection After the target is reflected, the antenna of the first microwave radar 1 receives the returned electromagnetic wave, that is, the first echo signal.
  • the second microwave radar 2 includes a second transmitter, which can be an antenna.
  • the distributed microwave radar imaging device 3 controls the antenna to emit a second detection electromagnetic wave to the detection target, and the second detection electromagnetic wave passes through the detection target. After reflection, the antenna of the second microwave radar 2 receives the returned electromagnetic wave, that is, the second echo signal.
  • the first detection electromagnetic wave emitted by the first microwave radar 1 may be a linear frequency modulated continuous wave (FMCW) signal.
  • the carrier frequency signal be exp(j2 ⁇ f c t)
  • Fast time is used to measure the propagation time of radio waves, while slow time is used to measure the moment of transmitting the pulse.
  • the relationship between these two times and full time is: Therefore, the first detection electromagnetic wave
  • the mathematical expression of 1 is:
  • f c is the center frequency
  • T p is the pulse width
  • ⁇ is the modulation frequency
  • t is the full time
  • fast time is fast time and t m is slow time.
  • the first detection electromagnetic wave emitted by the first microwave radar 1 After the detection target, a first echo signal is formed by reflection, and the receiving antenna of the first microwave radar 1 transmits the received first echo signal to the radar receiver, wherein the sampling point on the detection target reaches the first microwave signal.
  • the distance of radar 1 is The first echo signal received by the first microwave radar 1
  • the mathematical expression for 2 is:
  • the second detection electromagnetic wave emitted by the second microwave radar 2 can be the same as the first detection electromagnetic wave emitted by the first microwave radar, the specific mathematical expression is the same as the expression 1, and the mathematical expression of the second echo signal is the same as the expression 2.
  • Step 101a obtain the first echo signal received by the first microwave radar, and the first microwave radar is arranged at a first height;
  • Step 101b Acquire a second echo signal received by the second microwave radar, where the second microwave radar is set at a second height, wherein the first height is lower than the second height.
  • the first echo signal is a reflection signal obtained by the first detection electromagnetic wave emitted by the first microwave radar 1 to detect the detection target, and the first microwave radar 1 sends the obtained first echo signal to the distributed microwave of this embodiment.
  • Radar imaging device 3 is a reflection signal obtained by the first detection electromagnetic wave emitted by the first microwave radar 1 to detect the detection target, and the first microwave radar 1 sends the obtained first echo signal to the distributed microwave of this embodiment. Radar imaging device 3.
  • the first height refers to the height at which the first microwave radar 1 is set.
  • the first microwave radar 1 may be set at a lower position, so as to acquire data with a low viewing angle, so that aliasing does not occur in the upper imaging portion of the detection target.
  • the first microwave radar 1 arranged on the roadside sensing base station it can be arranged at a height equivalent to the position of the bottom of the vehicle; for the first microwave radar 1 arranged on the vehicle, it can be arranged at the lower part or the bottom of the vehicle body.
  • the second echo signal is a reflection signal obtained by the second detection electromagnetic wave emitted by the second microwave radar 2 to detect the detection target, and the second microwave radar 2 sends the obtained second microwave signal to the distributed microwave radar of this embodiment.
  • the second height refers to the height at which the second microwave radar 2 is set.
  • the second microwave radar 2 may be set at a higher position, so as to acquire data with a high viewing angle, so that aliasing does not occur in the lower imaging portion of the detection target.
  • the second microwave radar 2 installed on the roadside sensing base station it can be installed at a height equivalent to the top of the vehicle; for the second microwave radar 2 installed on the vehicle, it can be installed on the upper part or the top of the vehicle body.
  • the first height is lower than the second height, that is, the setting position of the first microwave radar 1 is located at the lower part of the second microwave radar 2 .
  • the fact that the first height is lower than the second height only defines the height dimension direction of the first microwave radar 1 and the second microwave radar 2, and the coordinate positions of the horizontal plane where the first microwave radar 1 and the second microwave radar 2 are located are not.
  • the coordinates of the two on the horizontal plane can be the same or different.
  • 101a and 101b may be in no particular order.
  • Step 102a Determine a first radar imaging result image of the detection target based on the first echo signal.
  • Step 102b Determine a second radar imaging result image of the detection target based on the second echo signal.
  • the distributed microwave radar imaging device 3 after receiving the first echo signal and the second echo signal, performs radar imaging processing on the echo data of the microwave radars of different viewing angles respectively, and obtains the imaging result image of each microwave radar, That is, the first radar imaging result image and the second radar imaging result image.
  • 102a and 102b may be in no particular order.
  • Step 103 Fusion of the first radar imaging result image and the second radar imaging result image to obtain a target fusion image.
  • the first radar imaging result image and the second radar imaging result image with different high and low viewing angles are placed at the same coordinates, and the two images are subjected to preferential extraction and complementary fusion processing.
  • the two images are finally fused to obtain a fused image, which is the target. Fused images.
  • the target fusion image can obtain target information with finer resolution and more accurate and complete target features.
  • the center registration of the first radar imaging result image and the second radar imaging result image can be performed, and an optimal threshold can be selected for the two-dimensional image.
  • the high imaging area is subjected to preferential interception and fusion processing, so that the lower boundary of the upper part of the imaging area of the detection target and the upper boundary of the lower part of the imaging area correspond to the reference line of the detection target, and the reference line can be selected as the center line.
  • the optimal threshold can be set in advance, and the preset specific value can be set by those skilled in the art based on experience, or determined by the specific effect of radar imaging.
  • the specific value and detailed settings for the selection of the optimal threshold in this application The method is not specifically limited.
  • Step 104 Determine the shape information or structure information of the detection target based on the target fusion image.
  • the distributed microwave radar imaging device 3 determines the shape information or structure information of the detection target.
  • the shape size information of the detection target includes two-dimensional size information including length and height information, and three-dimensional size information includes length, height, width information.
  • the structural information of the detection target can be obtained, for example, when the detection target is a vehicle, the information of the wheel and axle can be obtained.
  • the distributed microwave radar imaging realizes the complementary characteristics of high and low viewing angles, not only the length information of the detection target can be measured, but also the problem of inconsistent resolution in the height dimension of the detection target is solved, and the overall high resolution of the detection target is realized. imaging.
  • the partial images with echo aliasing problems are cropped, eliminating the imaging blind area of a single radar.
  • FIG. 4 is a schematic diagram of a method for determining a first radar imaging result based on a first echo signal according to an embodiment of the present application, and the method includes:
  • Step 201a Determine a first radar imaging initial image of the detection target based on the first echo signal.
  • various algorithms can be used to determine the initial image of the first radar imaging, and preferably, a frequency scaling (FSA) algorithm is used.
  • FSA frequency scaling
  • the embodiments of the present application are based on frequency scaling (FSA) radar imaging processing, and respectively perform radar imaging processing on radar data from different viewing angles to obtain an initial radar imaging image corresponding to each microwave radar.
  • the distributed microwave radar imaging device 3 After the distributed microwave radar imaging device 3 receives the first echo signal, it needs to perform dechirp processing in the signal processing, thereby reducing the AD sampling rate.
  • Dechirp is to use a time-fixed LFM signal with the same frequency and modulation frequency as a reference signal, and use the reference signal and the first echo signal for difference frequency processing.
  • R ref is the reference distance
  • the physical meanings represented by other letters in Expression 3 are the same as those in Expression 1-2, which will not be repeated here.
  • A is the amplitude constant
  • ⁇ is the modulation frequency
  • T p is the pulse width
  • R ref is the reference distance
  • C is the speed of light
  • ⁇ is the wavelength of the microwave radar
  • T p is the pulse width
  • the slow time t m has a value range of -T a /2 ⁇ t m ⁇ T a /2
  • T a is the time for the target to pass through the radar beam.
  • the FSA algorithm transforms the distance fast time scale in the range-Doppler domain to correct the spatial variability of the range migration. After processing by the FSA algorithm, the range migration correction can be completed.
  • Radar imaging processing including range processing and azimuth processing, completes the range operation, followed by azimuth processing, and in the azimuth, conventional azimuth pulse compression processing.
  • 1/ ⁇ is the scale factor of distance migration
  • ⁇ f a is the Doppler bandwidth in the azimuth direction
  • R B is the scene center.
  • FIG. 5 The initial imaging result of the first radar is shown in FIG. 5 , and the detected target is a vehicle in FIG. 5 .
  • FIG. 5 a is a schematic diagram of the actual size of the vehicle
  • FIG. 5 b is a schematic diagram of an initial imaging result of a first radar
  • FIG. 5 c is a schematic diagram of an initial imaging result of a second radar.
  • Step 202a Perform a first geometric deformation correction on the first microwave radar imaging initial image to obtain a first radar imaging result image.
  • the present embodiment adopts the synthetic aperture radar technology, and one of the characteristics of the synthetic aperture radar image is the phenomenon of shortening the distance to the slope.
  • the phenomenon of shortening the on-slope distance occurs because the position of the side-view radar image along the distance direction is determined by the slant distance of each target resolution unit from the radar. According to this regulation, the three-dimensional area is projected into a two-dimensional image, and the on-slope distance will inevitably be generated. shortening phenomenon.
  • the height of the first microwave radar is AB
  • the radar illuminates the detection target, such as a vehicle
  • the effective coverage distance beam angle is a
  • the height of the detection target to be observed is CE.
  • D and A are at the same horizontal height
  • the first microwave radar antenna radiates broadband electromagnetic waves from the detection target to be observed, the electromagnetic waves radiate to the side of the detection target, and are reflected back to be received by the first microwave radar receiver. Received by the receiver, that is, the echo of the detected target point D is first received by the receiver, followed by the echoes of points E and F, and finally the echo of point C. Among them, the echoes of point F and point E are the same, enter the receiver at the same time, the two echoes are indistinguishable in the time dimension, and the SAR imaging distance dimension information is distinguished according to the arrival time of the radar receiver.
  • the imaging result of the detection target is projected in the beam direction, the final imaging width is projected on AC, and the final imaging width of the detection target whose height is CE is CD', where the imaging information of DE and DF is aliased, D'F region in imaging swath.
  • the horizontal distance between the detection target and the first microwave radar is detected according to the geometric relationship of each parameter in FIG. 6 , and the horizontal distance is used as the reference line of the slant range projection.
  • the The imaging results obtained by the first microwave radar are subjected to geometric inversion parameter calculation to obtain the actual height of each sampling point on the detection target, so as to be corrected.
  • the imaging width of the detection target is defined as the width information of the height information of the detection target in the first radar imaging result image in the imaging of the detection target by the first microwave radar.
  • Step 201b determining a second radar imaging initial image of the detection target based on the second echo signal
  • Step 202b Perform second geometric deformation correction on the second radar imaging initial image to obtain a second radar imaging result image.
  • steps 201b and 202b are the same as those of steps 201a and 202a, which will not be repeated here.
  • first geometric deformation correction and the second geometric deformation correction include slant range projection, that is, the size and length of the detected target in the direction of the radar line of sight is projected onto the actual height of the target, and the specific method of the first geometric deformation correction and the second geometric deformation.
  • the specific method of correction is basically the same.
  • FIG. 8 is a schematic diagram of a specific method for correcting the first geometric deformation according to an embodiment of the application. The following takes the first geometric deformation correction as an example. On the basis of the above embodiment, as shown in FIG. 8 , the method may include the following steps:
  • Step 301a Based on the height of the first microwave radar and the shortest distance between the first microwave radar and the detection target, determine a first variation relationship between the first imaging width and height of the detection target, where the first variation relationship is: nonlinear functional relationship.
  • the geometric parameters required in this embodiment may include: the height of the first microwave radar, and the shortest distance between the first microwave radar and the detection target.
  • the height of the first microwave radar can be recorded when the first microwave radar is deployed. As shown in FIG. 6 , the first microwave radar is deployed at the position of point A, and point B is the ground. It can be known that the height of the first microwave radar is AB.
  • the distributed microwave radar imaging device 3 can detect the nearest gate of the detection target through Hough transform as the shortest distance between the first microwave radar and the detection target.
  • the position of the detection target is CE
  • the shortest distance between the first microwave radar and the detection target is AD.
  • the geometric inversion parameter calculation in this embodiment refers to obtaining the relationship between the radar imaging width and height of the detected target through the initial radar imaging image, so that oblique range projection can be performed.
  • the above shortest distance AD is used as the slant range projection reference line AD', and the geometric inversion parameter calculation is performed on the imaging result obtained by the first microwave radar.
  • W s is the imaging width of the detection target in the radar image
  • L D′C is the distance L AC from the first microwave radar to the detection target vertex minus the shortest distance L AD .
  • the height of the detected target is CE, which is compressed into the length of the imaging width D'C in the radar imaging result. It is worth noting that the DE segment and the FD segment of the original detection target are aliased during the imaging process, and the aliasing is in the D'C of the final imaging width. 'F' segment.
  • Equation 8 the first variation relationship between the detection target imaging width W s and the detection target height H CE is obtained as Equation 8,
  • x represents the height of the detection target sampling point
  • F(x) represents the imaging width W s corresponding to the detection target sampling point
  • x 0 represents the height H AB of the first microwave radar
  • y 0 represents the distance between the detection target and the first microwave radar The shortest distance L AD between them .
  • Step 301b Perform interpolation processing based on the first variation relationship to determine a first radar imaging result image.
  • FIG. 9 shows a first change graph of the imaging width and height of the detection target drawn according to the first change relationship. According to the change curve of the imaging width and height of the detection target, projection interpolation processing is performed on the initial imaging result of the first microwave radar to obtain the result after geometric deformation correction.
  • the specific method for correcting the second geometric deformation is the same as the method for correcting the first geometric deformation, and details are not repeated here.
  • the second microwave radar is set at a relatively high position, as shown in FIG. 10 , its positional relationship with the detection target determines that the second imaging width of the detection target is from the second microwave radar to the bottom of the detection target. The distance of the point minus the shortest distance.
  • Equation 9 the second variation relationship between the imaging width of the detection target and the height of the detection target is obtained as Equation 9
  • x represents the height of the detection target sampling point
  • F(x) represents the imaging width W s corresponding to the detection target sampling point
  • x 0 represents the height H AB of the second microwave radar
  • y 0 represents the distance between the detection target and the second microwave radar The shortest distance L AD between them .
  • oblique range projection is used, that is, the size and length of the detected target in the radar line of sight are projected onto the actual height of the target. Because the target is nonlinearly compressed in the radar line of sight, correction processing is required to obtain the actual height of the target.
  • the traditional oblique range projection adopts a linear stretching scheme, because its radar is mounted on a satellite or an aircraft and has a long operating distance. Compared with the width of the observation target and the operating distance between the radars, the ratio is small.
  • the nonlinear transformation in the oblique range projection can It can be ignored, and the approximate linear stretching process can be used; in this scheme, the ratio between the height of the observation target and the radar action distance is not small, and the nonlinear transformation in the slant range projection cannot be ignored.
  • the stretching scheme is more accurate and can more accurately describe the oblique projection results of the target, thereby improving the imaging resolution.
  • the distributed microwave radar imaging device 3 can further determine the shape information and structure information of the detection target.
  • the external dimension information of the detection target includes two-dimensional length and height information, or three-dimensional length, height, and width information.
  • the structure information of the detection target may be any conventional structure of the detection target, including the specific number and size of wheels, axles, and the like.
  • the method includes:
  • the interval equalization process is performed on the two dimensions of the two spliced and fused images, that is, taking the height dimension sampling unit Deltr_R of the side view target as the benchmark, and the length dimension (azimuth)
  • the sampling unit Deltr_A is interpolated or Compressed to a uniform sampling interval.
  • the specific interpolation or compression factor Deltr_times is calculated as follows:
  • the sampling unit of the height dimension and the sampling unit of the length dimension (azimuth) are as follows:
  • C is the speed of light
  • B is the radar transmission bandwidth
  • PRF is the radar sampling frequency
  • the above operation will obtain the result that the two-dimensional sampling units of the target height and length are equal. Further, the length and height information of the observation target is obtained by multiplying the number of scattering points and the width of the sampling unit.
  • Figure 12 is a geometric schematic diagram of the three-dimensional size information of the detection target.
  • AB is a schematic diagram of the first microwave radar
  • the detection target is a vehicle
  • the right figure HCJE is a schematic diagram of the vehicle
  • the dotted line is the position of the window of the vehicle.
  • the first microwave radar first illuminates the detection target, such as the left scattering area of the vehicle, and transmits it to the other side of the vehicle through the window.
  • the top of the other side of the vehicle forms an L-shaped angular inverse characteristic, resulting in strong scattering characteristics.
  • the height inversion of the CE segment on the left side of the vehicle has been completed, and the width information of the vehicle target is further inverted in the subsequent steps.
  • the specific inversion is as follows:
  • the first microwave radar detects the information of point J on the other side of the vehicle. We know the lengths of AJ, JI and AD. Now we need to solve the length of DI, which can be solved according to the right triangle AIJ:
  • the width DI of the vehicle target can be known by the above-mentioned solution.
  • the above can be constructed as a three-dimensional stereo imaging result of the target vehicle on the basis of obtaining the height of point J and the width DI information of the left side elevation of the relative vehicle.
  • the radar imaging method of the embodiment of the present application can image the detection target in the surrounding environment, and accurately give the size, structure, speed and position information of the detection target.
  • the roadside imaging device can charge the passing vehicle according to the size and structure of the detection target, and the vehicle-mounted imaging device can perform assisted driving operations on the vehicle.
  • the methods or steps in the foregoing embodiments may be implemented by a radar imaging device or a chip inside the radar imaging device.
  • FIG. 13 is a schematic structural diagram of a distributed microwave radar imaging device according to an embodiment of the present application.
  • the distributed microwave radar imaging device of the present application may include: a first acquisition unit 401 for acquiring a first echo signal received by a first microwave radar, the first microwave radar being set at a first height;
  • the second acquiring unit 402 acquires the second echo signal received by the second microwave radar, the second microwave radar is set at a second height, wherein the first height is lower than the second height;
  • the first imaging unit 403 determine the first radar imaging result image of the detected target based on the first echo signal;
  • the second imaging unit 404 determines the second radar imaging result image of the detected target based on the second echo signal;
  • the first imaging unit 403 is specifically configured to: determine a first radar imaging initial image of the detection target based on the first echo signal; perform a first radar imaging initial image on the first radar imaging initial image
  • the first radar imaging result image is obtained by geometric deformation correction
  • the second imaging unit 404 is specifically configured to: determine the second radar imaging initial image of the detection target based on the second echo signal; and the second radar imaging initial image
  • the second geometric deformation correction is performed to obtain a second radar imaging result image.
  • the first geometric deformation correction includes: based on the height of the first microwave radar and the shortest distance between the first microwave radar and the detection target, determining the difference between the first imaging width and the height of the detection target a first variation relationship, the first variation relationship is a nonlinear functional relationship; interpolation processing is performed based on the first variation relationship to determine a first radar imaging result image; wherein, the first imaging width of the detection target is The shortest distance is subtracted from the distance from the first microwave radar to the detection target vertex; the second geometric deformation correction includes: based on the height of the second microwave radar and the shortest distance between the second microwave radar and the detection target , determining a second variation relationship between the imaging width and height of the detection target, where the second variation relationship is a nonlinear functional relationship; performing interpolation processing based on the second variation relationship to determine a second radar imaging result image; The second imaging width of the detection target is the distance between the second microwave radar and the bottom point of the detection target minus the shortest distance.
  • the target fusion unit 405 is specifically configured to: splicing the upper part of the imaging region corresponding to the detection target in the first radar imaging correction image and the lower part of the imaging region corresponding to the detection target in the second imaging correction image Fusion to obtain the target fusion image.
  • the lower boundary of the upper partial imaging area and the upper boundary of the lower partial imaging area correspond to the reference line of the detection target.
  • the distributed microwave radar imaging apparatus further includes a target shape determination unit 406, which is specifically configured to: determine the shape information of the detected target based on the target fusion image.
  • the shape information includes the two-dimensional size or the three-dimensional size of the detection target.
  • the distributed microwave radar imaging device described above in this embodiment can be used to implement the technical solutions of the above method embodiments, and its implementation principles and technical effects are similar, and the functions of each module can refer to the corresponding descriptions in the method embodiments. It is not repeated here.
  • Embodiments of the present application further provide a distributed microwave radar imaging system, including a first microwave radar 1 , a second microwave radar 2 , and a distributed microwave radar imaging device 3 .
  • the distributed microwave radar imaging system of this embodiment can be used to implement the technical solutions of the foregoing method embodiments, and its implementation principle and technical effect are similar. Repeat.
  • This embodiment also provides a roadside microwave radar imaging system, including a first microwave radar 1, a second microwave radar 2, and a distributed microwave radar imaging device 3, wherein the first microwave radar 1 and the second microwave radar 2 are provided On the roadside, the detection target is a vehicle.
  • the roadside microwave radar imaging system of this embodiment can be used to implement the technical solutions of the above method embodiments, and its implementation principle and technical effect are similar. Repeat.
  • This embodiment also provides a vehicle, which includes a first microwave radar 1, a second microwave radar 2, and a distributed microwave radar imaging device 3, wherein the first microwave radar 1 and the second microwave radar 2 are arranged on the on the vehicle.
  • the vehicle of this embodiment can be used to implement the technical solutions of the above method embodiments, and its implementation principles and technical effects are similar, and the functions of each device can refer to the corresponding descriptions in the method embodiments, which will not be repeated here.
  • each functional module in the embodiments of the present application may be integrated into one processing module, or each module may exist physically alone, or two or more modules may be integrated into one module.
  • the above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules.
  • the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may be stored in a computer-readable storage medium.
  • the technical solution of the present application can be embodied in the form of a software product in essence or a part that contributes to the prior art or all or part of the technical solution, and the computer software product is stored in a storage inoculation , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, removable hard disk, ROM, RAM, magnetic disk or optical disk and other media that can store programs.
  • the above-mentioned embodiments it may be implemented in whole or in part by software, hardware, firmware or any combination thereof.
  • software it can be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated.
  • the computer may be a general purpose computer, special purpose computer, computer network, or other programmable device.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.).
  • the computer-readable storage medium can be any available ring that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more available media integrations.
  • the usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, solid State Disk (SSD), etc.).
  • the program instructions can be implemented in the form of software functional units and can be sold or used as a stand-alone product, and the memory can be any form of computer-readable storage medium.
  • the memory can be any form of computer-readable storage medium.
  • all or part of the technical solutions of the present application may be embodied in the form of software products, including several instructions to enable hundreds of millions of computer devices, specifically processors, to execute the target detection device in each embodiment of the present application. all or part of the steps.
  • the aforementioned computer-readable storage medium includes: U disk, removable hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disks or optical disks and other programs that can store programs medium.

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Abstract

一种分布式微波雷达成像方法及装置，该方法包括：获取第一微波雷达接收的第一回波信号，第一微波雷达设置在第一高度（步骤101a）；获取第二微波雷达接收的第二回波信号，第二微波雷达设置在第二高度，其中，第一高度低于第二高度（步骤101b）；基于第一回波信号确定检测目标的第一雷达成像结果图像（步骤102a）；基于第二回波信号确定检测目标的第二雷达成像结果图像（步骤102b）；将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像（步骤103）；基于目标融合图像确定检测目标的外形信息（步骤104）。该方法可以实现检测目标整体上高分辨率成像。

Description

一种分布式微波雷达的成像方法及装置 技术领域
本申请涉及雷达信号处理领域，特别涉及一种分布式微波雷达的成像方法及装置。
背景技术
微波雷达(Microwave Radar)是工作在微波波段探测的雷达，通常是指100M-200GHz频域，微波雷达的工作范围：1mm-1m，分为毫米波，厘米波和分米波等。其工作原理是向目标物体发射微波探测信号，然后将接收到的从目标物体反射回来的信号与发射的探测信号进行对比，信号处理后，获得目标物体的有关信息，如目标距离、方位、速度、姿态、形状、结构、尺寸等参数。
其中，毫米波雷达指工作在毫米波波段的雷达。通常毫米波是指30～300GHz频域(波长为1～10mm)的电磁波，毫米波的波长介于厘米波和光波之间，因此毫米波兼有微波制导和光电制导的优点。毫米波在5G通信、卫星遥感、导弹制导、电子对抗等领域有着广泛的应用，而近年来随着元器件水平的不断提升，电路设计、天线技术等相关技术日益发展和不断成熟，毫米波雷达的在道路检测领域、汽车自动驾驶领域的应用也获得了很大的发展。
然而，在道路检测领域以及汽车自动驾驶领域，毫米波雷达主要是用来进行单点目标的测距或测速，还没实现高分辨二维成像。
目前，利用合成孔径雷达技术(Synthetic Aperture Radar,SAR)采用侧视观测模式可以实现雷达成像处理，常规的雷达成像算法有：距离多普勒算法(Range Doppler Algorithm,RDA)、距离徙动算法(Range Migration Algorithm,RMA)、后向投影算法(Back Projection Algorithm,BPA)和频率变标算法(Frequency Scaling Algorithm,FSA)等。
然而上述算法在侧视感知成像应用过程中，无法克服SAR雷达固有的回波混叠问题，因而对观测目标存在成像盲区。回波混叠问题，即相对雷达高度对称的目标采样点位置，因为到达雷达的时间延迟相同，落入同一个采样单元，从而产生了混叠。因此，导致观测目标的成像分辨率较低。
发明内容
为了提高雷达成像装置对检测目标的成像分辨率，本申请提供了一种分布式微波雷达的成像方法及装置。
第一方面，本申请实施例提供一种分布式微波雷达成像方法，该方法包括：获取第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；获取第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中，所述第一高度低于所述第二高度；基于所述第一回波信号确定检测目标的第一雷达成像结果图像；基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像；将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像。
在本实现方式中，由于分布式微波雷达成像实现了高低视角互补特性，不但可以测量出检测目标长度信息，还解决了检测目标高度维度上分辨率不一致的难题，实现了检测目标整体上高分辨率成像。
并且，由于对高低雷达成像结果进行了融合，把发生回波混叠问题的部分图像进行裁剪，消除了回波混叠问题带来的影响，提升了检测目标的成像分辨率。
在一种可能的设计中，所述基于所述第一回波信号确定检测目标的第一雷达成像结果图像包括：基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像；对所述第一雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像；所述基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像包括：基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
在本实现方式中，通过对雷达成像初步图像进行几何形变矫正，消除了侧视感知成像过程中的迎坡缩短现象带来的影响，迎坡缩短现象造成了雷达成像初始图像的几何形变失真，通过几何形变矫正提升了检测目标的成像分辨率。
在一种可能的设计中，所述第一几何形变矫正包括：基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定检测目标的第一成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系；基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像；其中，所述检测目标的第一成像幅宽为所述第一微波雷达到所述检测目标顶点的距离减去所述最短距离；所述第二几何形变矫正包括：基于第二微波雷达的高度、第二微波雷达与所述检测目标的最短距离，确定检测目标的成像幅宽与高度之间的第二变化关系，所述第二变化关系为非线性的函数关系；基于所述第二变化关系进行插值处理，确定第二雷达成像结果图像；其中，所述检测目标的第二成像幅宽为所述第二微波雷达到所述检测目标底点的距离减去所述最短距离。
在本实现方式中，所述检测目标的高度和微波雷达作用距离之间的比值较大，采用斜距投影中非线性变换，相对于传统的遥感领域的线性拉伸方案更加精确，更能精确描述检测目标的斜距投影结果，因此提升了检测目标的成像分辨率。
在一种可能的设计中，将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像，包括：将第一雷达成像结果图像中对应所述检测目标的上部分成像区域与第二成像结果图像中对应所述检测目标的下部分成像区域进行拼接融合，得到目标融合图像。
在一种可能的设计中，所述上部分成像区域的下边界和所述下部分成像区域的上边界对应于所述检测目标的基准线。
在本实现方式中，通过对高低视角雷达成像结果图像进行拼接融合，选取了两种雷达成像结果中分辨率高的部分进行融合，克服了高度维度方向上分辨率不一致的问题，从而提高了图像整体的成像分辨率。
在一种可能的设计中，在执行将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像之后，还包括：基于目标融合图像确定所述检测目标的外形信息或结构信息。
在一种可能的设计中，所述外形信息包括所述检测目标的二维尺寸或三维立体尺寸。
在本实现方式中，基于目标融合图像确定检测目标的外形信息或结构信息，从而获得了准确的目标特征信息，提升了成像分辨率，也便于后续对检测目标的进一步处理。
第二方面，本申请实施例提供一种分布式微波雷达成像装置，包括：第一获取单元，获取第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；第二获取单元，获取第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中，所述第一高度低于所述第二高度；第一成像单元，基于所述第一回波信号确定检测目标的第一雷达成像结果图像；第二成像单元，基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像；目标融合单元，将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到 目标融合图像。
在一种可能的设计中，所述第一成像单元具体用于：基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像；对所述第一雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像；第二成像单元具体用于：基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
在一种可能的设计中，所述第一几何形变矫正包括：基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定检测目标的第一成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系；基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像；其中，所述检测目标的第一成像幅宽为所述第一微波雷达到所述检测目标顶点的距离减去所述最短距离；所述第二几何形变矫正包括：基于第二微波雷达的高度、第二微波雷达与所述检测目标的最短距离，确定检测目标的成像幅宽与高度之间的第二变化关系，所述第二变化关系为非线性的函数关系；基于所述第二变化关系进行插值处理，确定第二雷达成像结果图像；其中，所述检测目标的第二成像幅宽为所述第二微波雷达到所述检测目标底点的距离减去所述最短距离。
在一种可能的设计中，目标融合单元具体用于：将第一雷达成像矫正图像中对应所述检测目标的上部分成像区域与第二成像矫正图像中对应所述检测目标的下部分成像区域进行拼接融合，得到目标融合图像。
在一种可能的设计中，所述上部分成像区域的下边界和所述下部分成像区域的上边界对应于所述检测目标的基准线。
在一种可能的设计中，还包括目标外形确定单元，所述目标外形确定单元具体用于：基于目标融合图像确定所述检测目标的外形信息或结构信息。
在一种可能的设计中，所述外形信息包括所述检测目标的二维尺寸或三维立体尺寸。
第三方面，本申请实施例提供一种分布式微波雷达成像系统，包括第一微波雷达、第二微波雷达以及如第二方面任一项所述的装置。
第四方面，本申请实施例提供一种路侧微波雷达成像系统，包括第一微波雷达、第二微波雷达以及如第二方面任一项所述的装置，其中所述第一微波雷达、第二微波雷达设置在路侧，所述检测目标为车辆。
第五方面，本申请实施例提供一种车辆，包括第一微波雷达、第二微波雷达以及第二方面任一项所述的装置，其中所述第一微波雷达和第二微波雷达设置在所述车辆上。
第六方面，本申请实施例提供一种计算机可读存储介质，所述存储介质存储有计算机程序，所述计算机程序用于执行如第一方面任一项所述的成像方法。
第七方面，本申请实施例提供一种计算机程序产品，当其在计算机上运行时，使得计算机执行上述第一方面任一项所述的成像方法。
第八方面，本申请实施例提供一种电子设备，所述电子设备包括：处理器；用于存储所述处理器可执行指令的存储器；所述处理器，用于执行如第一方面任一项所述的目标对象的控制方法。
第九方面，本申请实施例提供一种芯片，包括至少一个处理器，所述处理器与存储器耦合，所述处理器用于读取存储器中的指令并根据所述指令执行第一方面任一项所述的方法。可以理解地，上述提供的任一种分布式微波雷达成像装置、可读存储介质、计算机程序产品、成像系统、车辆、电子设备，均可以由上文所提供的对应的方法来实现，因此，其所能达到 的有益效果可参考上文所提供的对应的方法中的有益效果，此处不再赘述。
附图说明
图1为本申请实施例提供的一种应用场景图的示意图；
图2为本申请实施例提供的一种微波雷达成像系统的结构示意图；
图3为本申请实施例提供的一种分布式微波雷达成像方法的流程示意图；
图4为本申请实施例提供的基于第一回波信号确定第一雷达成像结果的方法的流程示意图；
图5a为本申请实施例提供的一种车辆的实际尺寸示意图；
图5b为本申请实施例提供的第一雷达初始成像结果示意图；
图5c为本申请实施例提供的第二雷达初始成像结果示意图；
图6为本申请实施例提供的第一微波雷达对检测目标的成像幅宽示意图；
图7a为本申请实施例提供的第一雷达成像结果示意图；
图7b为本申请实施例提供的第二雷达成像结果示意图；
图8为本申请实施例提供的第一几何形变矫正具体方法的流程示意图；
图9为本申请实施例提供的检测目标成像幅宽和高度的变化曲线示意图；
图10为本申请实施例提供的第二微波雷达对检测目标的成像幅宽示意图；
图11本申请实施例提供的检测目标的外形尺寸方向示意图；
图12为本申请实施例提供的检测目标的三维尺寸几何示意图；
图13是本申请实施例提供的一种分布式微波雷达成像装置的结构示意图。
具体实施方式
为使本申请的目标、技术方案和优点更加清楚，下面将结合附图对本申请的实施方式作进一步地详细描述。
在对本发明实施例进行详细地解释说明之前，首先，对本发明实施例涉及的名词进行说明。
合成孔径雷达(Synthetic Aperture Radar,SAR)是一种脉冲方式工作的雷达系统，其信号在沿距离向和沿方位向的变化程度是不同的，沿距离向是快变化，沿方位向是慢变化。SAR感知成像，其具体成像机理是：方位向通过向观测区域不断地发射线性调频信号，形成虚拟长合成孔径阵列，即在方位向上利用合成孔径原理形成了成像的高分辨率；距离向通过发射超宽带的线性调频信号，并通过脉冲压缩技术获得高的距离向分辨率，从而获得两维高分辨率雷达感知图像。距离向为垂直于检测目标运动的方向，方位向为检测目标运动的方向。合成孔径雷达是一种主动式微波成像，具有一定的穿透性，能全天时全天候捕获光学影像中更多不易发现的目标信息，有很好的侦察作用。
调频连续波(Frequency Modulated Continuous Wave,FMCW)信号频率是时间的函数，两种广泛应用的调频形式是锯齿波调频和三角波调频，以锯齿波调频的FMCW信号为例，发射信号频率随时间按线性锯齿变化，目标回波为发射波形的复制波，双程回波延迟τ＝2R/C，其中，R为目标距离，C为光速。在调制周期内，差拍频率一部分为正，一部分为负，而且扫频周期中负差频的部分很小，这是因为通常设定的最大回波延迟相对于扫频周期来说也很小。
近年FMCW技术与SAR技术的结合，促使了重量轻、成本低、功耗低的高分辨成像雷达的诞生。
FMCW SAR一般发射大的时宽带宽积线性调频信号(并且发射信号占据接近整个脉冲重复周期)，实现距离向的高分辨。一方面，考虑到传统脉冲式SAR通常采用直采方式，与传统脉冲式SAR不同，FMCW SAR一般采用解线频调(Dechirp)接收方式，这是由于FMCW SAR的扫频周期达到毫秒级，如果采用直采接收方式，其距离向的采样点数将达到几百万点甚至更多，这么大的数据量对数据传输速率、处理速度都提出了很高要求，导致系统复杂度增加。另一方面，考虑到FMCW SAR一般作为小型化SAR应用，其距离测绘带宽通常较窄，因而采用Dechirp接收方式是合适的，此时系统采样频率只需要大于场景测绘带宽所对应的差频信号带宽，从而采样率可以大为降低，采样点数减少，系统设备简化，更适宜商业应用。
频率变标算法(Frequency Scaling Algorithm,FSA)，针对的是FMCW体制雷达下的Dechirp接收数据，它直接对解线频调后的信号进行处理。FSA是在距离-多普勒域对距离快时间进行变尺度操作校正距离徙动的空变性，首先将场景中所有散射点的距离徙动校正成参考距离处的，然后采用统一的参考函数进行剩余距离徙动的校正。整个算法只包含复乘和FFT操作，由于其精度高、运算量小，在Dechirp数据处理中得到了广泛的应用。因此，本申请拟采用频率变标算法进行成像处理。
其次，对本发明实施例涉及的应用环境进行说明。
图1为本申请实施例的一种应用场景的示意图，如图1所示，该应用场景包括第一微波雷达1、第二微波雷达2，检测目标为图中的车辆。
该第一微波雷达1和第二微波雷达2可以是按频段划分的毫米波雷达、X波段雷达、C波段雷达等任一一种或多种组合。该第一微波雷达1和第二微波雷达2可以是同一种类的雷达，也可以是不同种类的雷达。
具体的，毫米波雷达可以是24GHz、77GHz、79GHz、94GHz等波段的毫米波雷达。第一微波雷达1和第二微波雷达2也可以是不同波段的毫米波雷达的任一一种或多种组合，也可以是相同波段的毫米波雷达。
本申请实施例的分布式微波雷达成像方法可以应用于路侧检测系统、无人驾驶系统、或驾驶辅助预警系统等。路侧检测系统可以用于路侧感知，路侧感知是智慧交通系统及其他技术的数据获取基础，为高速收费稽查和城市道路监测提供依据，所需数据包括：车辆目标的长度、高度、车轴数、速度和间距、周边道路拥堵状态等。驾驶辅助预警系统包括：自动泊车、并线辅助、盲区检测等。
对于路侧检测系统，该检测目标可以是通过路侧检测系统的车辆，包括轿车、卡车、货车等。对于辅助驾驶系统，该检测目标可以使车辆、人、树木、马路牙子、障碍物等任意目标。
图2是本申请实施例提供的微波雷达成像系统结构示意图，包括第一微波雷达1、第二微波雷达2、分布式微波雷达成像装置3，其中，分布式微波雷达成像装置3分别与第一微波雷达1和第二微波雷达2连接。
分布式微波雷达成像装置3通过本申请实施例的分布式微波雷达成像方法对该雷达回波数据进行处理，从而对该检测目标进行成像，以确定目标信息，该目标信息反映了该检测目标的外形尺寸信息、速度、位置等信息。本申请实施例的分布式微波雷达成像方法可以提升检测目标的成像分辨率，其具体实施方式可以参见下述实施例的解释说明。
分布式微波雷达成像装置3可以包括：IO接口111、处理器112和用于存储所述处理器可执行指令的存储器113。
所述IO接口111可以包括输入/输出(I/O)接口。例如，输出设备可以是液晶显示器 (liquid crystal display，LCD),发光二级管(light emitting diode，LED)显示设备，阴极射线管(cathode ray tube，CRT)显示设备，或投影仪(projector)等。输入设备可以是鼠标、键盘、触摸屏设备或传感设备，以及至少两个成像传感器等。
所述处理器112可以是任何常规的处理器，诸如商业可获得的中央处理器(central processing unit，CPU)。替选地，该处理器可以是诸如专用集成电路(application specific integrated circuits，ASIC)或其它基于硬件的处理器的专用设备。尽管图2功能性地图示了处理器、存储器，但是本领域的普通技术人员应该理解该处理器、雷达成像装置、或存储器实际上可以包括可以或者可以不存储在相同的物理外壳内的多个处理器、雷达成像装置、或存储器。例如，存储器可以是硬盘驱动器或位于不同于分布式微波雷达成像装置3的外壳内的其它存储介质。因此，对处理器或雷达成像装置的引用将被理解为包括对可以或者不可以并行操作的处理器或计算机或存储器的集合的引用。不同于使用单一的处理器来执行此处所描述的步骤，诸如转向组件和减速组件的一些组件每个都可以具有其自己的处理器，所述处理器只执行与特定于组件的功能相关的计算。
在此处所描述的各个方面中，处理器可以位于远离该微波雷达并且与该微波雷达进行无线通信。在其它方面中，此处所描述的过程中的一些在布置于路侧基站或车辆内的处理器上执行而其它则由远程处理器执行，包括采取执行单一操纵的必要步骤。
在一些实施例中，存储器113可包含指令114(例如，程序逻辑)，指令114可被处理器112执行来执行分布式微波雷达成像装置3的各种功能，包括以上描述的那些功能。存储器113也可包含额外的指令，包括第一微波雷达1或第二微波雷达2中的一个或多个发送数据、从其接收数据、与其交互和/或对其进行控制的指令。
除了指令114以外，存储器113还可存储数据，例如检测目标的图像，或者在车载模式下，可以存储道路地图、路线信息，车辆的位置、方向、速度以及其它这样的车辆数据，以及其他信息。这种信息可在车辆在自主、半自主和/或手动模式中操作期间被车辆和计算机系统使用。
需要说明的是，上述分布式微波雷达成像装置3、第一微波雷达1和第二微波雷达2可以设置在相同的设备上，例如，路侧感知基站、车辆等。另一种可实现方式，第一微波雷达1和第二微波雷达2可以设置在不同的设备上，例如路侧不同的感知基站上等，分布式微波雷达成像装置3可以是终端设备，该成像装置可以与设置第一微波雷达1和第二微波雷达2的设备进行通信，以获得雷达回波数据。比如，路侧感知基站依据空口信道状态回传第一微波雷达1和第二微波雷达2的回波数据，或者处理后的雷达图像或者目标特征等检测信息给收费和检测系统，实现高速场景稽查收费和城市道路监测功能。
其中，终端设备可以是固定终端或者移动终端。固定终端可以是工业电脑等。移动终端也可以称为用户设备、接入终端、用户单元、用户站、移动站、移动台、用户终端、终端、无线通信设备、用户代理或用户装置。移动终端可以是车载设备、可穿戴设备、智能手机、平板电脑、个人数字处理设备、具有无限通信功能的手持设备或连接到无限调制解调器的其他处理设备等。
终端设备也可以由路侧基站的控制单元或者车辆控制单元代替。本实施例的雷达成像装置可以通过软件和/或硬件的方式实现。例如，该装置可以使上述终端设备或终端设备的内部芯片。下面以分布式微波雷达成像装置为执行主体对雷达成像方法进行说明。如图3所示，该方法可以包括如下步骤：
当该检测目标进入雷达波束检测范围内，该分布式微波雷达成像装置3控制第一微波雷 达1和第二微波雷达2开始对该检测目标进行雷达观测，直到该检测目标离开雷达波束。
所述第一微波雷达1包括第一发射器，该第一发射器可以是天线，该分布式微波雷达成像装置3控制天线向该检测目标发射第一检测电磁波，该第一检测电磁波经过该检测目标后进行反射，第一微波雷达1的天线接收返回的电磁波，即第一回波信号。
所述第二微波雷达2包括第二发射器，该第二发射器可以是天线，该分布式微波雷达成像装置3控制天线向该检测目标发射第二检测电磁波，该第二检测电磁波经过检测目标后进行反射，第二微波雷达2的天线接收返回的电磁波，即第二回波信号。
其中，对第一检测电磁波和第二检测电磁波可以选用多种类型的电磁波信号，但优选的，第一微波雷达1发射的第一检测电磁波可以为线性调频连续波(FMCW)信号。设载频信号为exp(j2πf ct)，脉冲信号以重复周期T依次发射，发射时刻t m＝mT(m＝0，1，2......)称为慢时间；以发射时刻为起点的时间用
Figure PCTCN2021102923-appb-000001
表示，称为快时间。快时间用来计量电波传播的时间，而慢时间是计量发射脉冲的时刻，这两个时间与全时间的关系为：
Figure PCTCN2021102923-appb-000002
因而第一检测电磁波
Figure PCTCN2021102923-appb-000003
的数学表达式1为：
Figure PCTCN2021102923-appb-000004
其中，
Figure PCTCN2021102923-appb-000005
f c为中心频率，T p为脉宽，γ为调频率，t为全时间，
Figure PCTCN2021102923-appb-000006
为快时间，t m为慢时间。
第一微波雷达1发射的第一检测电磁波
Figure PCTCN2021102923-appb-000007
经过该检测目标，反射形成第一回波信号，第一微波雷达1的接收天线将接收到的第一回波信号传递到雷达接收机中，其中，该检测目标上的采样点到第一微波雷达1的距离为
Figure PCTCN2021102923-appb-000008
第一微波雷达1接收到的第一回波信号
Figure PCTCN2021102923-appb-000009
的数学表达式2为：
Figure PCTCN2021102923-appb-000010
其中，A为常数，C为光速，其他参数与其在表达式1中的含义相同。优选的，第二微波雷达2发射的第二检测电磁波可以与第一微波雷达发射的第一检测电磁波相同，具体的数学表达式同表达式1，第二回波信号的数学表达式同表达式2。
步骤101a:获取所述第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；
步骤101b:获取所述第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中所述第一高度低于第二高度。
第一回波信号是第一微波雷达1发射的第一检测电磁波对该检测目标进行探测获取的反射信号，第一微波雷达1将获取的第一回波信号发送给本实施例的分布式微波雷达成像装置3。
如上述图1所示，第一高度是指第一微波雷达1设置的高度。具体的，第一微波雷达1可以设置在较低的位置，以便获取低视角的数据，使得该检测目标的上部成像部分不会发生混叠。例如，对于设置在路侧感知基站上的第一微波雷达1，可以设置在与车辆底部位置相当的高度；对于设置在车辆上的第一微波雷达1，可以设置在车体的下部或者底部。
第二回波信号是第二微波雷达2发射的第二检测电磁波对该检测目标进行探测获取的反射信号，第二微波雷达2将获取的第二微波信号发送给本实施例的分布式微波雷达成像装置3。
如上述图1所示，第二高度是指第二微波雷达2设置的高度。具体的，第二微波雷达2可以设置在较高的位置，以便获取高视角的数据，使得该检测目标的下部成像部分不会发生混叠。例如，对于设置在路侧感知基站上的第二微波雷达2，可以设置在与车辆顶部位置相当的高度；对于设置在车辆上的第二微波雷达2，可以设置在车体的上部或顶部。
其中，第一高度低于第二高度，即第一微波雷达1设置位置位于第二微波雷达2的下部。第一高度低于第二高度是仅仅对第一微波雷达1和第二微波雷达2的高度维度方向进行限定，而对于第一微波雷达1和第二微波雷达2所在的水平平面的坐标位置不进行限定，二者在水平平面上的坐标可以相同也可以不同。
其中，101a、101b可以不分先后顺序。
步骤102a：基于所述第一回波信号确定所述检测目标的第一雷达成像结果图像。
步骤102b：基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像。
其中，分布式微波雷达成像装置3接收到第一回波信号以及第二回波信号后，对不同视角的微波雷达的回波数据分别进行雷达成像处理，得到每个微波雷达的成像结果图像，即第一雷达成像结果图像和第二雷达成像结果图像。
其中，102a、102b可以不分先后顺序。
步骤103：将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像。
对高低视角不同的第一雷达成像结果图像和第二雷达成像结果图像放置在同一坐标下，对两幅图像进行择优提取、互补融合处理，两幅图像最后融合得到一幅融合后图像，即目标融合图像。目标融合图像可以获得分辨率更加精细，目标特征更加精确完整的目标信息。
具体的，可以将第一雷达成像结果图像与第二雷达成像结果图像进行中心配准，对两维图像进行最优门限选取，以此门限作为分辨分割截取的基准线，选择目标在分辨率较高成像区域进行择优截取融合处理，使得该检测目标上部分成像区域的下边界和下部分成像区域的上边界对应于检测目标的基准线，可以选择基准线为中心线。
其中，最优门限可以事先进行设置，且预设的具体数值可以由本领域技术人员根据经验进行设置，或者通过雷达成像的具体效果来确定，本申请对最优门限的选取的具体数值和详细设置方法不做具体限定。
步骤104：基于目标融合图像确定所述检测目标的外形信息或结构信息。
分布式微波雷达成像装置3在得到目标融合图像之后，确定该检测目标外形信息或结构信息，检测目标的外形尺寸信息包括二维尺寸信息包括长度和高度信息，以及三维尺寸信息包括长度、高度、宽度信息。进而还可以得到检测目标的结构信息，如当检测目标为车辆时， 可以得到车轮车轴的信息等。
本申请实施例，由于分布式微波雷达成像实现了高低视角互补特性，不但可以测量出检测目标长度信息，还解决了检测目标高度维度上分辨率不一致的难题，实现了检测目标整体上高分辨率成像。并且，由于对高低雷达成像结果进行了融合，把发生回波混叠问题的部分图像进行裁剪，消除了单一雷达存在的成像盲区。
进一步地，图4为本申请实施例的基于第一回波信号确定第一雷达成像结果的方法示意图，该方法包括：
步骤201a：基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像。
其中，可以采用多种算法确定第一雷达成像初始图像，优选的，选用频率变标(FSA)算法。本申请实施例基于频率变标(FSA)雷达成像处理，对不同视角的雷达数据分别进行雷达成像处理，得到每个微波雷达对应的雷达成像初始图像。
分布式微波雷达成像装置3接收到第一回波信号后，需要进行信号处理中的解线频调(Dechirp)处理，从而降低AD采样率。
解线频调(Dechirp)是用一时间固定，而频率、调频率相同的LFM信号作为参考信号，用该参考信号和第一回波信号作差频处理。设参考距离为R ref，则参考信号的数学表达式3为：
Figure PCTCN2021102923-appb-000011
其中,R ref为参考距离，表达式3中的其他字母代表的物理含义与表达式1-2的含义相同，这里就不再赘述。
解线频调脉压的数学表达式4为：
Figure PCTCN2021102923-appb-000012
其中，
Figure PCTCN2021102923-appb-000013
为第一回波信号，
Figure PCTCN2021102923-appb-000014
为参考信号的共轭。
通过表达式2-4，得到经解线频调处理后的差频输出，得到目标差频处理后回波的表示式如下：
Figure PCTCN2021102923-appb-000015
其中，A为幅度常数，γ为调频率，T p为脉冲宽度，R ref为参考距离，
Figure PCTCN2021102923-appb-000016
为检测目标和微波雷达瞬时距离，C为光速，λ为微波雷达波长,
Figure PCTCN2021102923-appb-000017
为距离快时间其取值范围为
Figure PCTCN2021102923-appb-000018
T p为脉宽，慢时间t m其取值范围为-T a/2≤t m≤T a/2，T a为目标通过雷达波束的时间。
FSA算法是在距离-多普勒域对距离快时间尺度变换，来进行校正距离徙动的空变性，经过该FSA算法处理，就可以完成距离徙动校正。雷达成像处理，包括距离向处理和方位向处理，完成了距离向操作，后续进行方位向处理，在方位向，进行常规方位脉冲压缩处理。
最后得到该检测目标的第一雷达初始成像结果为表达式6：
Figure PCTCN2021102923-appb-000019
表达式6中，1/β为距离徙动的尺度因子，Δf a为方位向的多普勒带宽，R B为场景中心，其他参数与前述公式的参数含义相同，在此不再赘述。
第一雷达初始成像结果如图5所示，在图5中检测目标为车辆。具体的，图5a为车辆的实际尺寸示意图，图5b为第一雷达初始成像结果示意图，图5c为第二雷达初始成像结果示意图。
将图5a-c三幅图进行比对，发现该车辆的初始成像结果受到了非线性压缩，b图上部的放大比例过大，下部的压缩比例过小。此外，车轮底部混叠了；c图下部放大比例过大，上部压缩比例过小。因此可知，第一雷达初步成像结果同时存在几何形变压缩和混叠特性，需要对第一微波雷达成像初始图像进行矫正。
步骤202a：对所述第一微波雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像。
如前所述，本实施例采用了合成孔径雷达技术，而合成孔径雷达图像的特征之一为迎坡距离缩短现象。产生迎坡距离缩短现象是因为侧视雷达成像图沿距离向的位置，由目标各分辨单元离雷达的斜距决定，按照这一规定三维地域投影成二维图像，就必然会产生迎坡距离缩短现象。
如图6所示，第一微波雷达高度为AB，雷达照射该检测目标，如车辆等，有效覆盖的距离向波束角是a，待观测的检测目标的高度是CE。其中，D和A在同一水平高度上，F点与E点关于D点对称，有AB＝DE＝DF。
第一微波雷达天线对待观测的检测目标辐射宽频带电磁波，电磁波辐射到该检测目标的侧面，反射回来被第一微波雷达接收机接收，距离越近的检测目标部件反射的雷达回波，越先被接收机接收即检测目标D点回波首先被接收机接收，其次是E点和F点回波，最后是C点回波。其中，F点和E点回波一样，同时进入接收机，两者回波是时间维度无法区分，而SAR成像距离维度信息就是根据到达雷达接收机时间区分的。
根据SAR雷达的成像特性，检测目标的成像结果投影在波束方向，最终成像幅宽投影在AC上，高度为CE的检测目标最终成像幅宽为CD’，其中DE和DF的成像信息混叠，在成像幅宽中D’F区域。本实施例中，根据图6中各个参数的几何关系，检测出该检测目标和第一微波雷达的水平间距，将水平间距作为斜距投影的基准线，结合第一微波雷达的高度信息，对第一微波雷达获得的成像结果进行几何反演参数计算，得到检测目标上各个采样点的实际高度，从而进行矫正。
其中，检测目标的成像幅宽定义为第一微波雷达对检测目标成像中，检测目标高度信息在第一雷达成像结果图像中的宽度信息。
步骤201b：基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；
步骤202b：对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
步骤201b和202b与步骤201a和202a的处理方法相同，这里就不再赘述。
第一雷达成像结果和第二雷达成像结果图像如图7a和7b所示。
在本实现方式中，通过对雷达成像初步图像进行几何形变矫正，消除了侧视感知成像过程中的固有的迎坡缩短现象带来的影响，迎坡缩短现象造成了雷达成像初始图像的几何形变失真，通过几何形变矫正提升了检测目标的成像分辨率。
进一步的，该第一几何形变矫正和第二几何形变矫正包括斜距投影，即将雷达视线方向的所述检测目标尺寸长度投影目标实际高度上，第一几何形变矫正的具体方法与第二几何形变矫正的具体方法基本相同。
图8为本申请实施例的第一几何形变矫正的具体方法的示意图，下面以第一几何形矫正为例在上述实施例的基础上，如图8所示，该方法可以包括如下步骤：
步骤301a：基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定检测目标的第一成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系。
本实施例中需要的几何参数可以包括：第一微波雷达的高度、第一微波雷达与检测目标的最短距离。
该第一微波雷达的高度，可以在部署该第一微波雷达时记录雷达安装高度。如图6所示，第一微波雷达部署在点A的位置，B点为地面，可知第一微波雷达高度为AB。
该第一微波雷达与检测目标的最短距离，分布式微波雷达成像装置3可以通过Hough变换检测出检测目标最近波门作为第一微波雷达与检测目标的最短距离。如图6所示，检测目标所在的位置为CE，第一微波雷达与检测目标的最短距离为AD。
本实施例中的几何反演参数计算，是指通过雷达成像初始图像得到检测目标的雷达成像幅宽与高度的关系，从而可以进行斜距投影。
如图6所示，将上述最短距离AD作为斜距投影基准线AD’，对第一微波雷达获得的成像结果进行几何反演参数计算。
第一微波雷达侧方位成像，将根据图6中SAR成像几何关系，得到几何反演参数计算关系：
Figure PCTCN2021102923-appb-000020
其中，W s为雷达图像中检测目标成像幅宽，该成像幅宽L D’C为所述第一微波雷达到所述检测目标顶点的距离L AC减去所述最短距离L AD。
检测目标高度为CE，在雷达成像结果中被压缩成了成像幅宽D’C长度，值得注意是原始检测目标DE段和FD段在成像过程中混叠，混叠在最终成像幅宽的D’F’段。
利用公式7得到检测目标成像幅宽W s和检测目标高度H CE的第一变化关系式为公式8，
Figure PCTCN2021102923-appb-000021
其中，x表示检测目标采样点的高度，F(x)表示检测目标采样点对应的成像幅宽W s，x 0表示第一微波雷达高度H AB，y 0表示检测目标与第一微波雷达之间的最短间距L AD。
步骤301b：基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像。
图9给出了根据第一变化关系绘制的检测目标成像幅宽和高度的第一变化曲线图。根据该检测目标成像幅宽和高度的变化曲线图，对第一微波雷达初始成像结果进行投影插值处理，得到几何形变校正后的结果。
第二几何形变矫正的具体方法与第一几何形变矫正的方法相同，具体不再赘述。但是由于第二微波雷达设置的位置较高，如图10所示，其与检测目标的位置关系决定了所述检测目标的第二成像幅宽为所述第二微波雷达到所述检测目标底点的距离减去所述最短距离。
与公式8的推导过程类似，得到检测目标成像幅宽和检测目标高度的第二变化关系式为公式9，
Figure PCTCN2021102923-appb-000022
其中，x表示检测目标采样点的高度，F(x)表示检测目标采样点对应的成像幅宽W s，x 0表示第二微波雷达高度H AB，y 0表示检测目标与第二微波雷达之间的最短间距L AD。
在本实现方式中通过斜距投影，即将雷达视线方向的所述检测目标尺寸长度投影目标实际高度上，因为目标在雷达视线方向是非线性压缩的，需要进行校正处理，得到目标实际高度。传统斜距投影是采用线性拉伸方案，因为其雷达装载在卫星或者飞机上，作用距离远，观测目标的宽度与雷达之间作用距离相比，比值很小，斜距投影中非线性变换可以忽略，采用近似的线性拉伸处理即可；而本方案中，观测目标高度和雷达作用距离之间的比值不小，斜距投影中非线性变换不可以忽略，因此，本实现方式相对于传统拉伸方案更加精确，更能精确描述目标的斜距投影结果，从而提高了成像分辨率。
进一步的，分布式微波雷达成像装置3在得到目标融合图像之后，可以进一步确定检测目标外形信息和结构信息。如图11所示，检测目标的外形尺寸信息包括二维长度和高度信息，或者三维的长度、高度、宽度信息。检测目标的结构信息可以是检测目标的任何常规的结构，包括车轮、车轴等的具体数量以及尺寸等。
在上述实施例的基础上，该方法包括：
对于二维尺寸信息，对两个拼接融合后的图像的两维进行间隔均衡处理，即以侧视目标高度维度采样单元Deltr_R做为基准，将长度维(方位向)的采样单元Deltr_A进行插值或压缩成统一的采样间距。具体插值或者压缩倍数Deltr_times计算如下：
Figure PCTCN2021102923-appb-000023
其中：高度维度采样单元和长度维(方位向)的采样单元分别如下：
Figure PCTCN2021102923-appb-000024
Figure PCTCN2021102923-appb-000025
其中，C为光速，B为雷达发射带宽，PRF为雷达采样频率。
上述操作即得到目标高度和长度两维采样单元相等结果。进一步根据散射点数和采样单元宽度相乘，得到观测目标的长度和高度信息。
图12为检测目标的三维尺寸信息几何示意图，如图12所示，AB为第一微波雷达示意图，检测目标为车辆，右侧图形HCJE为车辆的示意图，虚线部分为车辆的窗户所在位置。第一微波雷达首先照射到检测目标，如车辆的左侧散射区域，通过车窗透射到车辆的另一侧，车辆的另一侧顶端形成了L型角反特性，造成强散射特性。前面实施例所示，已完成了车辆左侧CE段的高度反演，后续为了进一步反演出车辆目标的宽度信息。具体反演如下：第一微波雷达探测到车辆另一侧顶端J点信息，我们已知AJ，JI和AD长度，现在需要求解DI长度，可以根据直角三角形AIJ进行求解：
(AI) 2+(JI) 2＝(AJ) 2
AI＝AD+Bus width
JI＝Bus hight-AB
(AD+Bus width) 2+(Bus hight-AB) 2＝(AJ) 2
通过上述带入求解可知车辆目标的宽度DI。
上述在得到J点的高度和相对车左侧立面的宽度DI信息基础上，可以构造成目标车辆的三维立体成像结果。
并且，本申请实施例的雷达成像方法可以对周围环境中的检测目标进行成像，准确的给出检测目标的尺寸、结构、速度和位置信息。以便后续进行相应的操作，例如，路侧成像装置可以根据检测目标的尺寸和结构对通行车辆进行收费，车载成像装置对车辆进行辅助驾驶操作。
可以理解的是，上述各个实施例中的方法或步骤，可以是由雷达成像装置或雷达成像装置内部的芯片实现的。
图13是本申请实施例的一种分布式微波雷达成像装置的结构示意图。如图13所示，本申请的分布式微波雷达成像装置可以包括：第一获取单元401，获取第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；第二获取单元402，获取第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中，所述第一高度低于所述第二高度；第一成像单元403，基于所述第一回波信号确定检测目标的第一雷达成像结果图像；第二成像单元404，基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像；目标融合单元405，将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像。
在一些实施例中，所述第一成像单元403具体用于：基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像；对所述第一雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像；第二成像单元404具体用于：基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
在一些实施例中，所述第一几何形变矫正包括：基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定检测目标的第一成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系；基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像；其中，所述检测目标的第一成像幅宽为所述第一微波雷达到所述检测目标顶点的距离减去所述最短距离；所述第二几何形变矫正包括：基于第二微波雷达的高度、第 二微波雷达与所述检测目标的最短距离，确定检测目标的成像幅宽与高度之间的第二变化关系，所述第二变化关系为非线性的函数关系；基于所述第二变化关系进行插值处理，确定第二雷达成像结果图像；其中，所述检测目标的第二成像幅宽为所述第二微波雷达与所述检测目标底点的距离减去所述最短距离。
在一些实施例中，目标融合单元具体405用于：将第一雷达成像矫正图像中对应所述检测目标的上部分成像区域与第二成像矫正图像中对应的检测目标的下部分成像区域进行拼接融合，得到目标融合图像。所述上部分成像区域的下边界和所述下部分成像区域的上边界对应于所述检测目标的基准线。
在一些实施例中，分布式微波雷达成像装置还包括目标外形确定单406，具体用于：基于目标融合图像确定所述检测目标的外形信息。所述外形信息包括所述检测目标的二维尺寸或三维立体尺寸。
本实施例以上所述的分布式微波雷达成像装置，可以用于执行上述方法实施例的技术方案，其实现原理和技术效果类似，其中各个模块的功能可以参考方法实施例中相应的描述，此处不再赘述。
本申请实施例还提供一种分布式微波雷达成像系统，包括第一微波雷达1、第二微波雷达2以及分布式微波雷达成像装置3。
本实施例的分布式微波雷达成像系统，可以用于执行上述各方法实施例的技术方案，其实现原理和技术效果类似，其中各个器件的功能可以参考方法实施例中相应的描述，此处不再赘述。
本实施例还提供一种路侧微波雷达成像系统，包括第一微波雷达1、第二微波雷达2以及分布式微波雷达成像装置3，其中所述第一微波雷达1、第二微波雷达2设置在路侧，所述检测目标为车辆。
本实施例的路侧微波雷达成像系统，可以用于执行上述各方法实施例的技术方案，其实现原理和技术效果类似，其中各个器件的功能可以参考方法实施例中相应的描述，此处不再赘述。
本实施例还提供一种车辆，该车辆包括第一微波雷达1、第二微波雷达2以及分布式微波雷达成像装置3，其中所述第一微波雷达1和第二微波雷达2设置在所述车辆上。
本实施例的车辆，可以用于执行上述各方法实施例的技术方案，其实现原理和技术效果类似，其中各个器件的功能可以参考方法实施例中相应的描述，此处不再赘述。
需要说明的是，本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。在本申请的实施例中的各功能模块可以集成在一个处理模块中，也可以是各个模块单独物理存在，也可以两个或两个以上模块集成在一个模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。
所述集成的模块如果以软件功能模块的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储接种中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器(processor)执行本申请各个实施例所述方法的全部或者部分步骤。而前述的存储介质包括：U盘、移动硬盘、ROM、RAM、磁碟或者光盘等各种可以存储程序的介质。
在上述实施例中，可以全部或者部分地通过软件、硬件、固件或者其任意组合来实现。 当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或者数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用戒指或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘solid State Disk(SSD)等。
所述程序指令可以以软件功能单元的形式实现并能够作为独立的产品销售或使用，所述存储器可以是任意形式的计算机可读取存储介质。基于这样的理解，本申请的技术方案全部或部分可以以软件产品的形式体现出来，包括若干指令用以使得亿台计算机设备，具体可以是处理器，来执行本申请各个实施例中目标检测装置的全部或部分步骤。而前述的计算机可读存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存储存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序的介质。
本实施例以上所述的电子设备，可以用于执行上述各方法实施例的技术方案，其实现原理和技术效果类似，其中各个器件的功能可以参考实施例中相应的描述，此处不再赘述。
最后应说明的是：以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (19)

  1. 一种分布式微波雷达成像方法，其特征在于，所述方法包括：
    获取第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；
    获取第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中，所述第一高度低于所述第二高度；
    基于所述第一回波信号确定检测目标的第一雷达成像结果图像；
    基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像；
    将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像。
  2. 根据权利要求1所述的方法，其特征在于，所述基于所述第一回波信号确定检测目标的第一雷达成像结果图像包括：
    基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像；对所述第一雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像；
    所述基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像包括：
    基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
  3. 根据权利要求2所述的方法，其特征在于，所述第一几何形变矫正包括：
    基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定所述检测目标的成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系；
    基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像；
    其中，所述检测目标的第一成像幅宽为所述第一微波雷达与所述检测目标顶点的距离减去所述最短距离；
    所述第二几何形变矫正包括：
    基于第二微波雷达的高度、第二微波雷达与所述检测目标的最短距离，确定所述检测目标的成像幅宽与高度之间的第二变化关系，所述第二变化关系为非线性的函数关系；
    基于所述第二变化关系进行插值处理，确定第二雷达成像结果图像；
    其中，所述检测目标的第二成像幅宽为所述第二微波雷达到所述检测目标底点的距离减去所述最短距离。
  4. 根据权利要求1-3中任一项所述的方法，其特征在于，将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像，包括：
    将第一雷达成像结果图像中对应所述检测目标的上部分成像区域与第二成像结果图像中对应所述检测目标的下部分成像区域进行拼接融合，得到目标融合图像。
  5. 根据权利要求4所述的方法，其特征在于，所述上部分成像区域的下边界和所述下部分成像区域的上边界对应于所述检测目标的基准线。
  6. 根据权利要求1-5中任一项所述的方法，其特征在于，在执行将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像之后，还包括：
    基于目标融合图像确定所述检测目标的外形信息或结构信息。
  7. 根据权利要求6所述的方法，其特征在于，所述外形信息包括所述检测目标的二维尺寸或三维立体尺寸。
  8. 一种分布式微波雷达成像装置，其特征在于，所述装置包括：
    第一获取单元，获取第一微波雷达接收的第一回波信号，所述第一微波雷达设置在第一高度；
    第二获取单元，获取第二微波雷达接收的第二回波信号，所述第二微波雷达设置在第二高度，其中，所述第一高度低于所述第二高度；
    第一成像单元，基于所述第一回波信号确定检测目标的第一雷达成像结果图像；
    第二成像单元，基于所述第二回波信号确定所述检测目标的第二雷达成像结果图像；
    目标融合单元，将第一雷达成像结果图像和第二雷达成像结果图像进行融合，得到目标融合图像。
  9. 根据权利要求8所述的装置，其特征在于，所述第一成像单元具体用于：
    基于所述第一回波信号确定所述检测目标的第一雷达成像初始图像；对所述第一雷达成像初始图像进行第一几何形变矫正得到第一雷达成像结果图像；
    第二成像单元具体用于：
    基于所述第二回波信号确定所述检测目标的第二雷达成像初始图像；对所述第二雷达成像初始图像进行第二几何形变矫正得到第二雷达成像结果图像。
  10. 根据权利要求11所述的装置，其特征在于，所述第一几何形变矫正包括：
    基于第一微波雷达的高度、第一微波雷达与所述检测目标的最短距离，确定所述检测目标的第一成像幅宽与高度之间的第一变化关系，所述第一变化关系为非线性的函数关系；
    基于所述第一变化关系进行插值处理，确定第一雷达成像结果图像；
    其中，所述检测目标的第一成像幅宽为所述第一微波雷达到所述检测目标顶点的距离减去所述最短距离；
    所述第二几何形变矫正包括：
    基于第二微波雷达的高度、第二微波雷达与所述检测目标的最短距离，确定检测目标的成像幅宽与高度之间的第二变化关系，所述第二变化关系为非线性的函数关系；
    基于所述第二变化关系进行插值处理，确定第二雷达成像结果图像；
    其中，所述检测目标的第二成像幅宽为所述第二微波雷达与所述检测目标底点的距离减去所述最短距离。
  11. 根据权利要求8-10中任一项所述的装置，其特征在于，目标融合单元具体用于：
    将第一雷达成像矫正图像中对应所述检测目标的上部分成像区域与第二成像矫正图像中对应所述检测目标的下部分成像区域进行拼接融合，得到目标融合图像。
  12. 根据权利要求11所述的装置，其特征在于，所述上部分成像区域的下边界和所述下部分成像区域的上边界对应于所述检测目标的基准线。
  13. 根据权利要求9-12中任一项所述的装置，其特征在于，还包括目标外形确定单元，所述目标外形确定单元具体用于：
    基于目标融合图像确定所述检测目标的外形信息或结构信息。
  14. 根据权利要求13所述的装置，其特征在于，所述外形信息包括所述检测目标的二维尺寸或三维立体尺寸。
  15. 一种分布式微波雷达成像系统，其特征在于，包括第一微波雷达、第二微波雷达以及权利要求8-14中任一项所述的装置。
  16. 一种路侧微波雷达成像系统，其特征在于，包括第一微波雷达、第二微波雷达以及权利要求8-14中任一项所述的装置，其中所述第一微波雷达、第二微波雷达设置在路侧，所述检测目标为车辆。
  17. 一种车辆，其特征在于，包括第一微波雷达、第二微波雷达以及权利要求8-14中任一项所述的装置，其中所述第一微波雷达和第二微波雷达设置在所述车辆上。
  18. 一种计算机可读存储介质，其特征在于，所述存储介质存储有计算机程序，所述计算机程序用于执行上述权利要求1-7任一所述的成像方法。
  19. 一种电子设备，其特征在于，所述电子设备包括：
    处理器；
    用于存储所述处理器可执行指令的存储器；
    所述处理器，用于执行上述权利要求1-7中任一所述的成像方法。
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