WO2023045804A1 - 数字全息快速成像方法 - Google Patents

数字全息快速成像方法 Download PDF

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WO2023045804A1
WO2023045804A1 PCT/CN2022/118463 CN2022118463W WO2023045804A1 WO 2023045804 A1 WO2023045804 A1 WO 2023045804A1 CN 2022118463 W CN2022118463 W CN 2022118463W WO 2023045804 A1 WO2023045804 A1 WO 2023045804A1
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imaging
array
image
target
phase
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French (fr)
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张继康
张艺恒
张继龙
俞晓琳
宋雨花
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苏州威陌电子信息科技有限公司
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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
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
    • 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
    • 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
    • G01S13/89—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
    • G01S13/904—SAR modes
    • G01S13/9064—Inverse SAR [ISAR]
    • 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8965—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using acousto-optical or acousto-electronic conversion techniques
    • G01S15/897—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using acousto-optical or acousto-electronic conversion techniques using application of holographic 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8977—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution
    • 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8997—Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques using synthetic aperture 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G01S17/90—Lidar systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0808—Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/14—Fourier, Walsh or analogous domain transformations, e.g. Laplace, Hilbert, Karhunen-Loeve, transforms
    • G06F17/141—Discrete Fourier transforms
    • G06F17/142—Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2222/00—Light sources or light beam properties
    • G03H2222/10—Spectral composition
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H3/00—Holographic processes or apparatus using ultrasonic, sonic or infrasonic waves for obtaining holograms; Processes or apparatus for obtaining an optical image from them

Definitions

  • the present invention relates to the technical fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, and target detection, imaging recognition, and wireless communication based on media such as sound, light, and electricity. applications in various fields.
  • Digital holographic imaging technology evolved from laser holographic imaging technology has high imaging resolution and is currently one of the preferred technologies for millimeter-wave active imaging, and related products have been promoted and applied in different fields at home and abroad.
  • the existing digital holographic imaging technology requires two operations of fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) in sequence (“FFT-phase compensation-IFFT” operation), and the amount of calculation is huge.
  • FFT fast Fourier transform
  • IFFT inverse fast Fourier transform
  • the configuration requirements of the hardware environment and computing resources are high, so the hardware price and operating cost are high.
  • the imaging speed is slow because of the need to perform FFT and IFFT operations twice in sequence.
  • the present invention provides a set of solutions.
  • the holographic data of the target can be obtained, and the image of the target can be obtained by imaging the holographic data.
  • the propagation phase shift introduced when the signal propagates through one-way R1 and R2 is:
  • the parts that are useful for imaging focus are:
  • ⁇ 1 is the propagation phase shift from the scattering source P to the array unit
  • ⁇ 2 is the propagation phase shift from the array unit to the image point Q
  • U is the object distance
  • V is the image distance
  • ( ⁇ , ⁇ ) is the target coordinates
  • (x, y) is the array unit coordinates
  • ( ⁇ , ⁇ ) is the image point coordinates.
  • the antenna array is equivalent to a lens with focal length F, then the effective phase shift of the lens unit is:
  • ⁇ L is the lens phase shift of the array unit
  • F is the focal length
  • the signal is sent from the antenna unit and received by the antenna unit after being reflected by the target.
  • the signal has experienced a two-way transmission with a distance of R1, and the corresponding phase delay is 2 ⁇ 1 .
  • the transceiver antenna unit sequentially transmits detection signals, and after the signal reflected by the target P reaches the transceiver antenna unit, it performs two-way processing in the form of spherical waves. Secondary scattering, then the field strength arriving at the image plane after different transmission paths R 1 , R 2 and two-way phase shift is:
  • Sinc represents the sinc function. It can be seen that there is a good mapping relationship between the image field distribution and the target.
  • the reflection signal received by the array needs to be processed by the following two-way phase shift during imaging:
  • IFFT means two-dimensional inverse fast Fourier transform.
  • the value ranges of ⁇ ⁇ and ⁇ ⁇ corresponding to the IFFT calculation results are: ⁇ ⁇ ⁇ [0,2 ⁇ ], ⁇ ⁇ ⁇ [0,2 ⁇ ], after the fftshift operation, the value ranges of ⁇ ⁇ and ⁇ ⁇ are transformed into: ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], the image at this time is the image that conforms to the actual distribution, and has a good linear mapping relationship with the source field.
  • the present invention provides a digital holographic fast imaging method, which is based on the principle of lens imaging, combined with electromagnetic field theory, according to the target signal received by the antenna array, weighted by the amplitude and phase of the unit signal, using high-efficiency Parallel algorithm to obtain the image field distribution corresponding to the target.
  • an efficient parallel algorithm is used to obtain the image field distribution corresponding to the target.
  • the specific algorithm is as follows:
  • j is the imaginary number unit
  • e Euler's constant
  • e is Euler's constant
  • e is the image field distribution
  • M is the number of array units in the x direction
  • N is the number of array units in the y direction
  • (x m , y n ) is the coordinate of the array unit
  • ( ⁇ , ⁇ ) is the coordinate of the image point
  • V is Image distance, that is, the distance from the imaging plane to the array plane
  • m and n are the serial numbers of the array unit in the x direction and y direction respectively, is the wave number
  • ⁇ is the wavelength
  • symbol ⁇ represents the summation operation.
  • the digital holographic fast imaging method of the present invention includes the following steps:
  • Step 1 performing amplitude weighting on the array unit signal to reduce the side lobe level
  • Step 2 Carry out scanning phase weighting on the array unit signal to adjust the central viewing angle direction of the imaging system
  • Step 3 Perform focus phase weighting on the array unit signals to achieve imaging focus
  • Step 4 Using an efficient parallel algorithm to perform fast imaging processing on the signal of the array unit;
  • Step 5 Calculate the coordinates of the image field, and perform coordinate inversion on the image field to obtain the position of the real target.
  • the method of amplitude weighting in step 1 of the method of the present invention includes but not limited to uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution and mixed weighting methods.
  • the scanning phase weighting in step 2 of the method of the present invention adjusts the central viewing angle direction of the imaging system, and the phase calculation formula of the scanning phase weighting is:
  • ⁇ x , ⁇ y are the array unit spacing in the x direction and y direction respectively
  • ⁇ ⁇ and ⁇ ⁇ are the scanning angle coordinates in the x and y directions when the central viewing angle direction points to the source coordinates ( ⁇ , ⁇ )
  • the calculation formula They are:
  • U is the object distance, that is, the distance from the plane where the target is located to the array plane.
  • the third step of the method of the present invention includes: using the focus phase weighting method to perform focus phase weighting on the array unit signals to achieve imaging focus, wherein:
  • the focus phase calculation formula for auto focus phase weighting is:
  • the focus phase calculation formula for zoom or fixed focus phase weighting is:
  • F is the focal length
  • F ⁇ U, F ⁇ V is the focal length
  • step 4 of the method of the present invention includes: using an efficient parallel algorithm to perform fast imaging processing on the amplitude and phase weighted signals of the array unit;
  • the efficient parallel algorithm includes but is not limited to two-dimensional or three-dimensional FFT, IFFT, Uniform FFT, sparse FFT, the calculation formula is:
  • symbol represents an efficient parallel algorithm function
  • A is the amplitude weighting coefficient of the array unit
  • ⁇ F is the focusing phase weighting coefficient
  • ⁇ S is the scanning phase weighting coefficient
  • the value ranges of ⁇ ⁇ and ⁇ ⁇ corresponding to the calculation results of the image field are: ⁇ ⁇ ⁇ [0,2 ⁇ ], ⁇ ⁇ ⁇ [0,2 ⁇ ], after the fftshift operation, the value ranges of ⁇ ⁇ and ⁇ ⁇ are transformed into: ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], the image at this time conforms to the image of the actual distribution:
  • step five of the method of the present invention includes: performing coordinate calculation on the image field obtained by the efficient parallel algorithm, and performing coordinate inversion on the image field to obtain the distribution of real targets; wherein:
  • ⁇ x , ⁇ y are the array element spacing in the x direction and y direction, respectively
  • U is the object distance
  • ( ⁇ , ⁇ ) are the source coordinates.
  • the unit spacing of the transceiver antenna is set to avoid image aliasing.
  • the present invention also relates to the application of the above method in the fields of optical imaging, microwave imaging, radar detection, sonar, ultrasonic imaging, sound, light, and electrical target detection, imaging recognition, and wireless communication.
  • the simplified formula applicable to long-distance imaging at this time is:
  • U is the object distance, as image, symbol represents an efficient parallel algorithm function
  • A is the amplitude weighting coefficient of the array unit
  • ⁇ F is the focusing phase weighting coefficient
  • ⁇ S is the scanning phase weighting coefficient
  • j is the imaginary number unit
  • e is Euler’s constant
  • the width can be obtained by one operation The distribution of objects within the viewing angle.
  • the digital holographic fast imaging method of the present invention has the following advantages:
  • the present invention adopts the algorithm framework of "phase compensation-IFFT". Compared with the traditional holographic imaging algorithm, it eliminates the FFT calculation link that requires high hardware resources and slow operation speed, greatly reduces the calculation amount and improves the calculation speed.
  • the phase compensation when imaging at a long distance, the phase compensation is also negligible. At this time, it is equivalent to performing an IFFT operation to realize imaging of a long-distance target.
  • the method of the present invention has a good application prospect and can be widely used in the field of target detection and wireless communication technology using sound, light, electricity, etc. as the medium.
  • the detection medium is electromagnetic waves
  • the technology is applicable to microwave imaging, radar detection, Wireless communication, synthetic aperture radar, and inverse synthetic aperture radar
  • the detection medium is sound waves and ultrasonic waves
  • this technology is applicable to sonar, ultrasonic imaging, and synthetic aperture sonar
  • when the detection medium is light this technology is applicable to optical imaging, synthetic aperture optical imaging.
  • Fig. 1 is the coordinate system of the digital holographic imaging system of the present invention.
  • Fig. 2 is an algorithm block diagram of the digital holographic imaging method of the present invention.
  • Embodiment 1 A digital holographic fast imaging method (see accompanying drawings 1-2), this method is based on the principle of lens imaging, combined with electromagnetic field theory, according to the target signal received by the antenna array, weighted by the amplitude and phase of the unit signal, using Efficient parallel algorithm to obtain the image field distribution corresponding to the target.
  • the specific algorithm is as follows:
  • j is the imaginary number unit
  • e Euler's constant
  • e is Euler's constant
  • e is the image field distribution
  • M is the number of array units in the x direction
  • N is the number of array units in the y direction
  • (x m , y n ) is the coordinate of the array unit
  • ( ⁇ , ⁇ ) is the coordinate of the image point
  • V is Image distance, that is, the distance from the imaging plane to the array plane
  • m and n are the serial numbers of the array unit in the x direction and y direction respectively, is the wave number
  • ⁇ is the wavelength
  • symbol ⁇ represents the summation operation.
  • this method includes the following steps:
  • Step 1 performing amplitude weighting on the array unit signal to reduce the side lobe level
  • the amplitude weighting methods include uniform distribution, cosine weighting, Hamming window, Taylor distribution, Chebyshev distribution and mixed weighting methods.
  • Step 2 Carry out scanning phase weighting on the array unit signal to adjust the central viewing angle direction of the imaging system
  • the scanning phase weighting adjusts the viewing angle direction of the center of the imaging system
  • the phase calculation formula of the scanning phase weighting is:
  • m and n are the serial numbers of the array elements in the x direction and y direction respectively, Respectively, the phase difference between adjacent elements of the array in the x and y directions, and their calculation formulas are:
  • ⁇ x , ⁇ y are the array element spacing in the x direction and y direction respectively, the symbol sin represents a sine function, ⁇ ⁇ and ⁇ ⁇ are the scans in the x and y directions when the direction of the central viewing angle points to the source coordinates ( ⁇ , ⁇ ) Angular coordinates, the calculation formulas are:
  • U is the object distance, that is, the distance from the target plane to the array plane
  • tan -1 represents the arc tangent function
  • Step 3 Perform focus phase weighting on the array unit signals to achieve imaging focus
  • the focus phase calculation formula for auto focus phase weighting is:
  • the focus phase calculation formula for zoom or fixed focus phase weighting is:
  • F is the focal length
  • F ⁇ U, F ⁇ V is the focal length
  • Step 4 Using an efficient parallel algorithm to perform fast imaging processing on the signal of the array unit;
  • the high-efficiency parallel algorithm includes: adopting a high-efficiency parallel algorithm to perform fast imaging processing on the amplitude and phase weighted signals of the array unit;
  • the high-efficiency parallel algorithm includes two-dimensional or three-dimensional FFT, IFFT, non-uniform FFT, and sparse FFT, and its calculation formula is:
  • symbol represents an efficient parallel algorithm function
  • A is the amplitude weighting coefficient of the array unit
  • ⁇ F is the focusing phase weighting coefficient
  • ⁇ S is the scanning phase weighting coefficient
  • the value ranges of ⁇ ⁇ and ⁇ ⁇ corresponding to the calculation results of the image field are: ⁇ ⁇ ⁇ [0,2 ⁇ ], ⁇ ⁇ ⁇ [0,2 ⁇ ].
  • the value ranges of ⁇ ⁇ and ⁇ ⁇ are transformed into: ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], ⁇ ⁇ ⁇ [- ⁇ , ⁇ ], the image at this time conforms to the image of the actual distribution:
  • Step 5 Calculate the coordinates of the image field, and perform coordinate inversion on the image field to obtain the position of the real target;
  • it includes: coordinate calculation of the image field obtained by the efficient parallel algorithm, and coordinate inversion of the image field to obtain the distribution of real targets; among them:
  • ⁇ x , ⁇ y are the array element spacing in the x direction and y direction, respectively
  • U is the object distance
  • ( ⁇ , ⁇ ) are the source coordinates.
  • the unit spacing of the transceiver antenna is set to avoid image aliasing.
  • the working frequency is 30GHz
  • the spacing between antenna elements is half a wavelength
  • the array size is 32*32.
  • One target is located in the normal direction of the array, and the other target is 20° away from the normal direction.
  • the distance between the target and the plane where the antenna array is located is 1m. Attached Figure 3.
  • the working frequency is 30GHz
  • the spacing between antenna elements is half a wavelength
  • the array size is 32*32.
  • One target is located in the normal direction of the array, and the other target is 20° away from the normal direction.
  • the distance between the target and the plane where the antenna array is located is 1000m. Attached Figure 4.
  • the simplified formula applicable to long-distance imaging is:
  • U is the object distance, as image, symbol represents an efficient parallel algorithm function
  • A is the amplitude weighting coefficient of the array unit
  • ⁇ F is the focusing phase weighting coefficient
  • ⁇ S is the scanning phase weighting coefficient
  • j is the imaginary number unit
  • e is Euler’s constant
  • the width can be obtained by one operation The distribution of objects within the viewing angle.

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Abstract

一种数字全息快速成像方法及其在光学成像、微波成像、雷达探测、无线通信、声呐、超声成像以及基于声、光、电等媒介的目标探测与成像识别技术领域中的应用。数字全息快速成像方法基于透镜成像原理，结合电磁场理论，根据天线阵列接收到的目标信号，通过单元信号的幅度、相位加权，采用高效并行算法，获得目标对应的像场分布。具有运算量小、硬件成本降低、成像速度快、可适用于远距离成像等优点，可广泛应用于光学成像、微波成像、雷达探测、声呐、超声成像以及声、光、电等为媒介的目标探测、成像识别、无线通信领域。

Description

数字全息快速成像方法 技术领域
本发明涉及光学成像、微波成像、雷达探测、声呐、超声成像以及基于声、光、电等媒介的目标探测、成像识别、无线通信技术领域，具体涉及一种数字全息快速成像方法及其在上述各领域中的应用。
背景技术
从激光全息成像技术演变而来的数字全息成像技术，成像分辨率高，是目前毫米波主动成像的首选技术之一，并且国内外已有相关产品在不同领域推广应用。
但传统数字全息成像技术仍具有许多缺陷和不足，主要包括：
1)运算量大，成本高、速度慢
现有数字全息成像技术成像时需要依次进行快速傅里叶变换(FFT)和快速傅里叶逆变换(IFFT)两次运算(“FFT-相位补偿-IFFT”运算)，运算量极大，对硬件环境和计算资源的配置要求高，故而造成硬件价格和运行成本均较高，此外，由于需要依次进行FFT和IFFT两次运算，因此成像速度较慢。
2)无法远距离成像
现有数字全息成像技术中，当目标距离较远时，相位补偿可忽略不计，此时相当于进行“FFT-IFFT”运算，会造成成像失真甚至成像失败。
此外，现有技术“微波阵列快速成像方法”(CN 112612024 A)，但该方法不适用于近距离数字全息成像应用，当成像距离较近时，该方法因成像效果 差、分辨率低而无法获得满意的成像效果。
发明内容
为了克服传统数字全息成像技术存在的上述缺陷和不足，本发明提供了一套解决方案。
如附图1所示，建立成像***的坐标系，其中：P为目标，Q为目标的像，天线阵列位于z＝0的平面上，X表示收发天线单元。依次打开收发天线单元，记录目标的散射信号，当整个天线阵列扫描完毕时，即可获得目标的全息数据，对此全息数据进行成像处理即可获得目标的像。
信号经过单程R1、R2传播时引入的传播相移为：
Figure PCTCN2022118463-appb-000001
其中对成像聚焦有用的部分为：
Figure PCTCN2022118463-appb-000002
其中，φ 1为散射源P到阵列单元的传播相移，φ 2为阵列单元到像点Q的传播相移，
Figure PCTCN2022118463-appb-000003
为波数，U为物距，V为像距；(ζ，ξ)为目标坐标，(x，y)为阵列单元坐标，(δ，σ)为像点坐标。
将天线阵列等效为焦距为F的透镜，则透镜单元的有效相移为：
Figure PCTCN2022118463-appb-000004
其中，φ L为阵列单元的透镜相移，F为焦距。
在全息成像***中，信号从天线单元发出，到目标反射后被天线单元所接收，信号经历了路程为R1的双程传输，对应的相位延迟为2φ 1。在成像处理时， 需要对透镜单元相移、R2传播相移都作双程处理：收发天线单元依次发射探测信号，经过目标P反射后的信号到达收发天线单元后，以球面波的形式进行二次散射，则经过不同的传输路径R 1、R 2和双程相移后到达像平面处的场强为：
Figure PCTCN2022118463-appb-000005
其中，
Figure PCTCN2022118463-appb-000006
为像场分布，
Figure PCTCN2022118463-appb-000007
为目标反射信号。代入φ 1、φ 2、φ L的表达式整理后得：
Figure PCTCN2022118463-appb-000008
其中，
Figure PCTCN2022118463-appb-000009
当满足成像条件时：
Figure PCTCN2022118463-appb-000010
此时有Ψ 1＝0，令
Figure PCTCN2022118463-appb-000011
整理得：
Figure PCTCN2022118463-appb-000012
对于理想矩形透镜阵面：
Figure PCTCN2022118463-appb-000013
代入上式进行定积分得：
Figure PCTCN2022118463-appb-000014
其中Sinc表示辛克函数。可以看出，像场分布与目标之间存在良好的映射关系。
对于实际的全息成像离散阵列***，假设收发天线单元接收到的目标发射信号为E，成像时则需要对阵列接收到的反射信号作如下双程相移处理：
Figure PCTCN2022118463-appb-000015
其中，
Figure PCTCN2022118463-appb-000016
为阵列单元接收到的场，A mn为阵列单元的幅度加权系数。将上式展开并整理后得：
Figure PCTCN2022118463-appb-000017
其中，
Figure PCTCN2022118463-appb-000018
当满足成像条件时：
Figure PCTCN2022118463-appb-000019
此时有ψ 1＝0。
Figure PCTCN2022118463-appb-000020
令x m＝x 0+mΔ x，y n＝y 0+nΔ y，m、n分别为阵列单元x方向与y方向的序号，Δ x、Δ y分别为x方向、y方向的阵列单元间距，(x 0,y 0)为阵列起始单元坐标。带入上式化简整理得：
Figure PCTCN2022118463-appb-000021
其中，
Figure PCTCN2022118463-appb-000022
上式右边的系数满足
Figure PCTCN2022118463-appb-000023
反映了像场的空间波动特性，对成像基本无影响，可忽略。求和运算可用二维IFFT进行快速求解，则像场计算公式为：
Figure PCTCN2022118463-appb-000024
其中，IFFT表示二维快速傅里叶逆变换。IFFT计算结果对应的ω δ、ω σ取值范围为：ω δ∈[0,2π]、ω σ∈[0,2π]，进行fftshift运算后将ω δ、ω σ取值范围变换为：ω δ∈[-π,π]、ω σ∈[-π,π]，此时的像才是符合实际分布的像，并且与源场之间具有良好的线性映射关系。
Figure PCTCN2022118463-appb-000025
结合阵列天线理论，有ω δ＝2kΔ xsinθ δ、ω σ＝2kΔ ysinθ σ，方向图无栅瓣条件为：
Figure PCTCN2022118463-appb-000026
最后，采用阵列天线理论对像点扫描角坐标进行修正：
Figure PCTCN2022118463-appb-000027
在上述认识的基础上，本发明提供了一种数字全息快速成像方法，该方法基于透镜成像原理，结合电磁场理论，根据天线阵列接收到的目标信号，通过 单元信号的幅度、相位加权，采用高效并行算法，获得目标对应的像场分布。
进一步地，该方法中所述通过单元信号的幅度、相位加权，采用高效并行算法，获得目标对应的像场分布，其具体算法如下：
Figure PCTCN2022118463-appb-000028
其中：j为虚数单位，e为欧拉常数，
Figure PCTCN2022118463-appb-000029
为像场分布，
Figure PCTCN2022118463-appb-000030
为阵列单元接收到的目标信号，A mn为阵列单元幅度加权系数，
Figure PCTCN2022118463-appb-000031
为聚焦相位加权系数，
Figure PCTCN2022118463-appb-000032
为扫描相位加权系数，M为x方向的阵列单元数量，N为y方向的阵列单元数量，(x m，y n)为阵列单元的坐标，(δ，σ)为像点的坐标，V为像距，即成像平面到阵列平面的距离，m、n分别为阵列单元x方向与y方向的序号，
Figure PCTCN2022118463-appb-000033
为波数，λ为波长，符号∑代表求和运算。
具体而言，本发明数字全息快速成像方法包括下述步骤：
步骤一：对阵列单元信号进行幅度加权以降低副瓣电平；
步骤二：对阵列单元信号进行扫描相位加权以调整成像***中心视角方向；
步骤三：对阵列单元信号进行聚焦相位加权以实现成像聚焦；
步骤四：采用高效并行算法，对阵列单元的信号进行快速成像处理；
步骤五：解算像场坐标，对像场进行坐标反演获得真实目标的位置。
进一步地，本发明方法步骤一中所述幅度加权的方法包括但不限于均匀分布、余弦加权、汉明窗、Taylor分布、切比雪夫分布及混合加权方法。
进一步地，本发明方法步骤二中所述扫描相位加权调整成像***中心视角方向，其扫描相位加权的相位计算公式为：
Figure PCTCN2022118463-appb-000034
其中：
Figure PCTCN2022118463-appb-000035
分别为x、y方向的阵列相邻单元之间的相位差，其计算公式分别为：
Figure PCTCN2022118463-appb-000036
Figure PCTCN2022118463-appb-000037
其中：Δ x、Δ y分别为x方向、y方向的阵列单元间距，θ ζ、θ ξ为中心视角方向指向源坐标(ζ，ξ)时的x、y方向的扫描角坐标，其计算公式分别为：
Figure PCTCN2022118463-appb-000038
Figure PCTCN2022118463-appb-000039
其中：U为物距，即目标所在平面到阵列平面的距离。
进一步地，本发明方法步骤三中包括：利用聚焦相位加权方法，对阵列单元信号进行聚焦相位加权以实现成像聚焦，其中：
自动对焦相位加权的聚焦相位计算公式为：
Figure PCTCN2022118463-appb-000040
变焦或定焦相位加权的聚焦相位计算公式为：
Figure PCTCN2022118463-appb-000041
其中，F为焦距，且F<U、F<V。
进一步地，本发明方法步骤四中包括：采用高效并行算法，对阵列单元的幅度、相位加权后的信号进行快速成像处理；所述高效并行算法包含但不限于二维或三维FFT、IFFT、非均匀FFT、稀疏FFT，其计算公式为：
Figure PCTCN2022118463-appb-000042
其中：
Figure PCTCN2022118463-appb-000043
为像，符号
Figure PCTCN2022118463-appb-000044
表示高效并行算法函数，
Figure PCTCN2022118463-appb-000045
为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数；
像场计算结果对应的ω δ、ω σ取值范围为：ω δ∈[0,2π]、ω σ∈[0,2π]，进行fftshift 运算后将ω δ、ω σ取值范围变换为：ω δ∈[-π,π]、ω σ∈[-π,π]，此时的像是符合实际分布的像：
Figure PCTCN2022118463-appb-000046
进一步地，本发明方法步骤五中包括：对高效并行算法获得的像场进行坐标解算，并对像场进行坐标反演，获得真实目标的分布情况；其中：
对于IFFT类的高效并行算法，像场扫描角坐标计算公式为：
Figure PCTCN2022118463-appb-000047
Figure PCTCN2022118463-appb-000048
对于FFT类的高效并行算法，像场扫描角坐标计算公式为：
Figure PCTCN2022118463-appb-000049
Figure PCTCN2022118463-appb-000050
像的直角坐标计算公式为：
δ＝V tanθ δ，
σ＝V tanθ σ；
真实目标的坐标反演计算公式为：
Figure PCTCN2022118463-appb-000051
Figure PCTCN2022118463-appb-000052
其中，Δ x、Δ y分别为x方向、y方向的阵列单元间距，U为物距，(ζ，ξ)为源坐标。
进一步地，本发明方法中设置收发天线的单元间距
Figure PCTCN2022118463-appb-000053
以避免出现成像混叠现象。
同时，本发明还涉及上述方法在光学成像、微波成像、雷达探测、声呐、超声成像以及声、光、电目标探测、成像识别、无线通信领域中的应用。
此外，本发明还提供了一种数字全息快速成像方法，所述快速成像方法用于远距离成像，包括：采用上述高效并行算法计算像场，通过选取U＝∞，则有φ F＝0，此时适用于远距离成像的简化公式为：
Figure PCTCN2022118463-appb-000054
其中，U为物距，
Figure PCTCN2022118463-appb-000055
为像，符号
Figure PCTCN2022118463-appb-000056
表示高效并行算法函数，
Figure PCTCN2022118463-appb-000057
为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数，j为虚数单位，e为欧拉常数，通过一次运算获得宽视角范围内的目标分布情况。
综上，本发明数字全息快速成像方法具有以下优点：
1)运算量小，硬件成本低，成像速度快
本发明采用“相位补偿-IFFT”的算法架构，相比传统全息成像算法，去掉了对硬件资源要求高、运行速度慢的FFT运算环节，大幅减少了运算量，提高了运算速度。
2)可适用于远距离成像
本发明中，当远距离成像时，相位补偿同样可忽略不计，此时相当于进行IFFT运算，可实现对远距离目标的成像。
另外，本发明方法具有良好的应用前景，可广泛应用于以声、光、电等为媒介的目标探测及无线通信技术领域，当探测媒介为电磁波时，本技术适用于微波成像、雷达探测、无线通信、合成孔径雷达、逆合成孔径雷达；当探测媒介为声波、超声波时，本技术适用于声呐、超声成像、合成孔径声呐；当探测媒介为光时，本技术适用于光学成像、合成孔径光学成像。
附图说明
为了更清楚地说明现有技术和本发明实施例的技术方案，下面将对现有技术和本发明实施例描述中所需要使用的附图作简要介绍，显而易见地，以下附 图仅仅是本发明中记载的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明数字全息成像***坐标系。
图2为本发明数字全息成像方法的算法框图。
图3为传统全息成像与本发明全息成像近距离成像结果对比(U＝1m)，其中：(a)为传统全息成像，(b)为本发明全息成像。
图4为传统全息成像与本发明全息成像远距离成像结果对比(U＝1000m)，其中：(a)为传统全息成像，(b)为本发明全息成像。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚，下面将结合具体实施例及相应的附图对本发明的技术方案进行清楚、完整地描述。显然，所描述的实施例仅是本发明一部分实施例，而不是全部的实施例，本发明还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本发明的精神下进行各种修饰或改变。
同时，应理解，本发明的保护范围并不局限于下述特定的具体实施方案；还应当理解，本发明实施例中使用的术语是为了描述特定的具体实施方案，而不是为了限制本发明的保护范围。
实施例1：一种数字全息快速成像方法(参见附图1-2)，本方法基于透镜成像原理，结合电磁场理论，根据天线阵列接收到的目标信号，通过单元信号的幅度、相位加权，采用高效并行算法，获得目标对应的像场分布，其具体算法如下：
Figure PCTCN2022118463-appb-000058
其中：j为虚数单位，e为欧拉常数，
Figure PCTCN2022118463-appb-000059
为像场分布，
Figure PCTCN2022118463-appb-000060
为阵列单元接 收到的目标信号，A mn为阵列单元幅度加权系数，
Figure PCTCN2022118463-appb-000061
为聚焦相位加权系数，
Figure PCTCN2022118463-appb-000062
为扫描相位加权系数，M为x方向的阵列单元数量，N为y方向的阵列单元数量，(x m，y n)为阵列单元的坐标，(δ，σ)为像点的坐标，V为像距，即成像平面到阵列平面的距离，m、n分别为阵列单元x方向与y方向的序号，
Figure PCTCN2022118463-appb-000063
为波数，λ为波长，符号∑代表求和运算。
具体而言，本方法包括下述步骤：
步骤一：对阵列单元信号进行幅度加权以降低副瓣电平；
其中，所述幅度加权的方法包括均匀分布、余弦加权、汉明窗、Taylor分布、切比雪夫分布及混合加权方法。
步骤二：对阵列单元信号进行扫描相位加权以调整成像***中心视角方向；
其中，所述扫描相位加权调整成像***中心视角方向，其扫描相位加权的相位计算公式为：
Figure PCTCN2022118463-appb-000064
其中：m、n分别阵列单元x方向与y方向的序号，
Figure PCTCN2022118463-appb-000065
分别为x、y方向的阵列相邻单元之间的相位差，其计算公式分别为：
Figure PCTCN2022118463-appb-000066
Figure PCTCN2022118463-appb-000067
其中：Δ x、Δ y分别为x方向、y方向的阵列单元间距，符号sin代表正弦函数，θ ζ、θ ξ为中心视角方向指向源坐标(ζ，ξ)时的x、y方向的扫描角坐标，其计算公式分别为：
Figure PCTCN2022118463-appb-000068
Figure PCTCN2022118463-appb-000069
其中：U为物距，即目标所在平面到阵列平面的距离，符号tan -1代表反正切函数。
步骤三：对阵列单元信号进行聚焦相位加权以实现成像聚焦；
具体包括：利用聚焦相位加权方法，对阵列单元信号进行聚焦相位加权以实现成像聚焦，其中：
自动对焦相位加权的聚焦相位计算公式为：
Figure PCTCN2022118463-appb-000070
变焦或定焦相位加权的聚焦相位计算公式为：
Figure PCTCN2022118463-appb-000071
其中，F为焦距，且F<U、F<V。
步骤四：采用高效并行算法，对阵列单元的信号进行快速成像处理；
具体包括：采用高效并行算法，对阵列单元的幅度、相位加权后的信号进行快速成像处理；所述高效并行算法包含二维或三维FFT、IFFT、非均匀FFT、稀疏FFT，其计算公式为：
Figure PCTCN2022118463-appb-000072
其中：
Figure PCTCN2022118463-appb-000073
为像，符号
Figure PCTCN2022118463-appb-000074
表示高效并行算法函数，
Figure PCTCN2022118463-appb-000075
为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数；
像场计算结果对应的ω δ、ω σ取值范围为：ω δ∈[0,2π]、ω σ∈[0,2π]，进行fftshift运算后将ω δ、ω σ取值范围变换为：ω δ∈[-π,π]、ω σ∈[-π,π]，此时的像是符合实际分布的像：
Figure PCTCN2022118463-appb-000076
步骤五：解算像场坐标，对像场进行坐标反演获得真实目标的位置；
具体包括：对高效并行算法获得的像场进行坐标解算，并对像场进行坐标反演，获得真实目标的分布情况；其中：
对于IFFT类的高效并行算法，像场扫描角坐标计算公式为：
Figure PCTCN2022118463-appb-000077
Figure PCTCN2022118463-appb-000078
对于FFT类的高效并行算法，像场扫描角坐标计算公式为：
Figure PCTCN2022118463-appb-000079
Figure PCTCN2022118463-appb-000080
像的直角坐标计算公式为：
δ＝V tanθ δ，
σ＝V tanθ σ；
真实目标的坐标反演计算公式为：
Figure PCTCN2022118463-appb-000081
Figure PCTCN2022118463-appb-000082
其中，Δ x、Δ y分别为x方向、y方向的阵列单元间距，U为物距，(ζ，ξ)为源坐标。
此外，本发明方法中设置收发天线的单元间距
Figure PCTCN2022118463-appb-000083
以避免出现成像混叠现象。
实施例2：本发明数字全息快速成像(实施例1方法)与传统全息成像的近距离成像结果对比(U＝1m)，包括：
工作频率30GHz，天线单元间距为半波长，阵列规模32*32，一个目标位 于阵列法线方向，另一个目标偏离法线方向20°，目标距离天线阵列所在平面距离均为1m，成像结果对比见附图3。
实施例3：本发明数字全息快速成像(实施例1方法)与传统全息成像的远距离成像结果对比(U＝1000m)，包括：
工作频率30GHz，天线单元间距为半波长，阵列规模32*32，一个目标位于阵列法线方向，另一个目标偏离法线方向20°，目标距离天线阵列所在平面距离均为1000m，成像结果对比见附图4。
实施例4：一种数字全息快速成像方法，该方法用于远距离成像，包括：采用实施例1所述的高效并行算法计算像场，通过选取U＝∞，则有φ F＝0，此时适用于远距离成像的简化公式为：
Figure PCTCN2022118463-appb-000084
其中，U为物距，
Figure PCTCN2022118463-appb-000085
为像，符号
Figure PCTCN2022118463-appb-000086
表示高效并行算法函数，
Figure PCTCN2022118463-appb-000087
为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数，j为虚数单位，e为欧拉常数，通过一次运算获得宽视角范围内的目标分布情况。
本发明中的各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似的部分互相参见即可。
以上所述仅为本发明的实施例而已，并不用于限制本发明。对于本领域技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原理之内所作的任何修改、替换等，均应包含在本发明的权利要求保护范围之内。

Claims (10)

  1. 一种数字全息快速成像方法，其特征在于，所述方法基于透镜成像原理，结合电磁场理论，根据天线阵列接收到的目标信号，通过单元信号的幅度、相位加权，采用高效并行算法，获得目标对应的像场分布，其具体算法如下：
    Figure PCTCN2022118463-appb-100001
    其中：j为虚数单位，e为欧拉常数，
    Figure PCTCN2022118463-appb-100002
    为像场分布，
    Figure PCTCN2022118463-appb-100003
    为阵列单元接收到的目标信号，A mn为阵列单元幅度加权系数，
    Figure PCTCN2022118463-appb-100004
    为聚焦相位加权系数，
    Figure PCTCN2022118463-appb-100005
    为扫描相位加权系数，M为x方向的阵列单元数量，N为y方向的阵列单元数量，(x m，y n)为阵列单元的坐标，(δ，σ)为像点的坐标，V为像距，即成像平面到阵列平面的距离，m、n分别为阵列单元x方向与y方向的序号，
    Figure PCTCN2022118463-appb-100006
    为波数，λ为波长，符号∑代表求和运算。
  2. 根据权利要求1所述的方法，其特征在于，所述方法包括下述步骤：
    步骤一：对阵列单元信号进行幅度加权以降低副瓣电平；
    步骤二：对阵列单元信号进行扫描相位加权以调整成像***中心视角方向；
    步骤三：对阵列单元信号进行聚焦相位加权以实现成像聚焦；
    步骤四：采用高效并行算法，对阵列单元的信号进行快速成像处理；
    步骤五：解算像场坐标，对像场进行坐标反演获得真实目标的位置。
  3. 根据权利要求2所述的方法，其特征在于，步骤一中所述幅度加权的方法包括均匀分布、余弦加权、汉明窗、Taylor分布、切比雪夫分布及混合加权方法。
  4. 根据权利要求2所述的方法，其特征在于，步骤二中所述扫描相位加权调整成像***中心视角方向，其扫描相位加权的相位计算公式为：
    Figure PCTCN2022118463-appb-100007
    其中：
    Figure PCTCN2022118463-appb-100008
    分别为x、y方向的阵列相邻单元之间的相位差，其计算公式分别为：
    Figure PCTCN2022118463-appb-100009
    Figure PCTCN2022118463-appb-100010
    其中：Δ x、Δ y分别为x方向、y方向的阵列单元间距，符号sin表示正弦函数，θ ζ、θ ξ为中心视角方向指向源坐标(ζ，ξ)时的x、y方向的扫描角坐标，其计算公式分别为：
    Figure PCTCN2022118463-appb-100011
    Figure PCTCN2022118463-appb-100012
    其中：U为物距，即目标所在平面到阵列平面的距离，符号tan -1代表反正切函数。
  5. 根据权利要求4所述的方法，其特征在于，步骤三中包括：利用聚焦相位加权方法，对阵列单元信号进行聚焦相位加权以实现成像聚焦，其中：
    自动对焦相位加权的聚焦相位计算公式为：
    Figure PCTCN2022118463-appb-100013
    变焦或定焦相位加权的聚焦相位计算公式为：
    Figure PCTCN2022118463-appb-100014
    其中，F为焦距，且F<U、F<V。
  6. 根据权利要求4所述的方法，其特征在于，步骤四中包括：采用高效并行算法，对阵列单元的幅度、相位加权后的信号进行快速成像处理；所述高效并行算法包含二维或三维FFT、IFFT、非均匀FFT、稀疏FFT，其计算公式为：
    Figure PCTCN2022118463-appb-100015
    其中：
    Figure PCTCN2022118463-appb-100016
    为像，符号
    Figure PCTCN2022118463-appb-100017
    表示高效并行算法函数，
    Figure PCTCN2022118463-appb-100018
    为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数；
    像场计算结果对应的ω δ、ω σ取值范围为：ω δ∈[0,2π]、ω σ∈[0,2π]，进行fftshift运算后将ω δ、ω σ取值范围变换为：ω δ∈[-π,π]、ω σ∈[-π,π]，此时的像是符合实际分布的像：
    Figure PCTCN2022118463-appb-100019
  7. 根据权利要求4所述的方法，其特征在于，步骤五中包括：对高效并行算法获得的像场进行坐标解算，并对像场进行坐标反演，获得真实目标的分布情况；其中：
    对于IFFT类的高效并行算法，像场扫描角坐标计算公式为：
    Figure PCTCN2022118463-appb-100020
    Figure PCTCN2022118463-appb-100021
    对于FFT类的高效并行算法，像场扫描角坐标计算公式为：
    Figure PCTCN2022118463-appb-100022
    Figure PCTCN2022118463-appb-100023
    像的直角坐标计算公式为：
    δ＝V tanθ δ，
    σ＝V tanθ σ；
    真实目标的坐标反演计算公式为：
    Figure PCTCN2022118463-appb-100024
    Figure PCTCN2022118463-appb-100025
    其中，Δ x、Δ y分别为x方向、y方向的阵列单元间距，U为物距，(ζ，ξ)为源坐标。
  8. 根据权利要求4所述的方法，其特征在于，设置收发天线的单元间距
    Figure PCTCN2022118463-appb-100026
    Figure PCTCN2022118463-appb-100027
    以避免出现成像混叠现象。
  9. 根据权利要求1-8任一项所述的方法，其特征在于，该方法应用在光学成像、微波成像、雷达探测、声呐、超声成像以及声、光、电目标探测、成像识别、无线通信领域中。
  10. 一种数字全息快速成像方法，其特征在于，所述快速成像方法用于远距离成像，包括：
    采用如权利要求6所述的高效并行算法计算像场，通过选取U＝∞，则有φ F＝0，此时适用于远距离成像的简化公式为：
    Figure PCTCN2022118463-appb-100028
    其中，U为物距，
    Figure PCTCN2022118463-appb-100029
    为像，符号
    Figure PCTCN2022118463-appb-100030
    表示高效并行算法函数，
    Figure PCTCN2022118463-appb-100031
    为阵列单元接收到的目标散射场，A为阵列单元幅度加权系数，φ F为聚焦相位加权系数，φ S为扫描相位加权系数，j为虚数单位，e为欧拉常数，通过一次运算获得宽视角范围内的目标分布情况。
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