Fast wavenumber domain imaging of molecular apertures based on rectangular boundary MIMO arrays

Abstract

The present invention specifically relates to a rapid wavenumber domain imaging method for molecular apertures based on a rectangular-boundary MIMO array. The method comprises: receiving an echo signal from a target and preprocessing the echo signal to obtain a corresponding intermediate frequency signal; dividing the intermediate frequency signal based on a subaperture partitioning strategy for the antenna array to determine subaperture data corresponding to each subaperture; performing a two-dimensional spatial Fourier transform on the subaperture data to obtain wavenumber domain data corresponding to the subaperture data; performing subaperture imaging on the wavenumber domain data based on a Fourier transform, and generating a three-dimensional image of the target based on the subaperture imaging. This method can reduce imaging time and significantly improve imaging efficiency.

Description

Technical Field

[0001] The present invention relates to the field of image processing technology, and in particular to a fast wavenumber domain imaging method, storage medium, computer program product, and electronic equipment based on a molecular aperture of a rectangular boundary MIMO array. Background Art

[0002] Millimeter wave (MMW) multiple-input-multiple-output (MIMO) antenna arrays are widely used in near-field imaging. Due to their high resolution and penetrating properties, millimeter waves offer unique advantages in security imaging, nondestructive testing, and medical diagnosis. A common MIMO antenna array is the rectangular boundary MIMO array, which is increasingly popular due to its wide coverage and high gain. The imaging algorithm for rectangular boundary MIMO arrays is a key step in imaging.

[0003] Existing imaging algorithms still have certain defects, including low failure rate and high requirements for hardware equipment, such as computing power and storage space. For example, the Back Projection (BP) algorithm is a classic imaging algorithm. Since the BP algorithm does not have approximations, the BP algorithm has the highest imaging quality. This algorithm uses coherent accumulation imaging, which has low timeliness and cannot be effectively applied in practice. The Chirp Scaling (CS) algorithm and the Frequency Scaling (FS) algorithm are far-field algorithms. When introduced into the near field, some of the algorithm's own approximations are still retained, resulting in low imaging quality and failure to meet specific business needs. The Range Migration Algorithm (RMA) is a classic frequency-domain algorithm. MIMO-RMA can be used with MIMO antenna arrays. MIMO-RMA offers high imaging quality and high speed. However, for large-scale antenna arrays like MIMO rectangular boundary arrays, the acquired echo data has four spatial dimensions. The conversion to the frequency domain requires a significant amount of storage space, placing high demands on the hardware computing platform. The SAR-FFT algorithm converts MIMO data into multiple single-input-multiple-output (SIMO) data for processing. When the number of antennas is large, a large number of SIMO data streams must be processed, resulting in low timeliness.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] The present invention provides a fast wavenumber domain imaging method of molecular aperture based on a rectangular boundary MIMO array, a storage medium, a computer program product, and an electronic device, which can greatly shorten the imaging time and reduce the demand for storage space, thereby overcoming the defects of the existing technology to a certain extent.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0007] According to a first aspect of the present invention, there is provided a method for rapid wavenumber domain imaging of a molecular aperture based on a rectangular boundary MIMO array, the method comprising:

[0008] Receive the echo signal of the target and pre-process the echo signal to obtain the corresponding intermediate frequency signal;

[0009] The intermediate frequency signal is divided based on the sub-aperture division strategy of the antenna array, and the sub-aperture data corresponding to each sub-aperture is determined;

[0010] Performing Fourier transform based on the two-dimensional spatial domain on the sub-aperture data to obtain wavenumber domain data corresponding to the sub-aperture data;

[0011] Sub-aperture imaging is performed on the wavenumber domain data based on Fourier transform, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging.

[0012] In some exemplary embodiments, preprocessing the echo signal includes:

[0013] The echo signal is subjected to a mixing operation and a de-skewing operation in sequence.

[0014] In some exemplary embodiments, performing sub-aperture imaging on the wavenumber domain data based on Fourier transform, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging, includes:

[0015] Convolution processing is performed on the wavenumber domain data using a preconfigured phase factor to obtain multi-dimensional data; wherein the data dimensions of the multi-dimensional data include: a two-dimensional wavenumber domain dimension and a time domain dimension;

[0016] Performing Fourier transform on the multi-dimensional data in the time domain to obtain data to be processed that is converted into the frequency domain;

[0017] Corresponding slice data is extracted from the data to be processed, and sub-aperture imaging is generated according to the slice data, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging.

[0018] In some exemplary embodiments, the phase factor includes: a first phase factor, a second phase factor;

[0019] The convolution process is performed on the wavenumber domain data using the preconfigured phase factor to obtain multi-dimensional data, including:

[0020] Performing convolution processing on the wavenumber domain data using the first phase factor to obtain intermediate data;

[0021] The intermediate data is convolved using a second phase factor to obtain the multi-dimensional data.

[0022] In some exemplary embodiments, extracting corresponding data slices from the data to be processed, generating sub-aperture imaging according to the data slices, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging includes:

[0023] Based on a distance division rule preconfigured for an imaging range, slice data extraction is performed on the data to be processed to obtain slice data of a specific distance;

[0024] Perform inverse Fourier transform in the wavenumber domain on the slice data at a specific distance to obtain sub-aperture imaging in the spatial domain;

[0025] The sub-aperture images corresponding to each sub-aperture are combined and processed to obtain the full-aperture image corresponding to a specific distance;

[0026] The imaging range is sliced ​​and tomographically processed based on preconfigured distance division rules to obtain three-dimensional imaging results.

[0027] In some exemplary embodiments, performing slice tomography processing on the imaging range based on a preconfigured distance division rule to obtain a three-dimensional imaging result includes:

[0028] Traversing each specific distance based on a preconfigured distance division rule to obtain full-aperture imaging corresponding to each specific distance;

[0029] The full-aperture images corresponding to each specific distance are combined and processed to obtain a three-dimensional imaging result.

[0030] In some exemplary embodiments, the method further comprises:

[0031] A sub-aperture partitioning strategy is configured according to a task type and / or a target type, and sub-aperture partitioning is performed on the antenna array based on the sub-aperture partitioning strategy.

[0032] According to a second aspect of the present invention, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array is implemented.

[0033] According to a third aspect of the present invention, a computer program product is provided, on which a computer program is stored, and when the computer program is executed by a processor, the computer program implements the above-mentioned fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array.

[0034] According to a fourth aspect of the present invention, there is provided an electronic device, comprising:

[0035] processor; and

[0036] a memory for storing executable instructions of the processor;

[0037] The processor is configured to implement the above-mentioned fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array when executing the executable instructions.

[0038] The fast wavenumber domain imaging method for molecular apertures based on rectangular boundary MIMO arrays provided in an embodiment of the present invention pre-divides the antenna array into sub-apertures. After converting the echo signal into an intermediate frequency signal, the sub-aperture data corresponding to each sub-aperture can be determined. This allows for dimensionality reduction of the echo data, obtaining three-dimensional sub-aperture data corresponding to each sub-aperture, and reducing the amount of data for each sub-aperture. The obtained sub-aperture data can be processed in parallel, reducing imaging time and reducing the storage space requirements of hardware devices. Imaging the echo data of each sub-aperture using a wavenumber domain method can effectively improve imaging efficiency and reduce imaging time.

[0039] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are incorporated into and constitute a part of this specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0041] Figure 1 A schematic diagram schematically illustrates a fast wavenumber domain imaging method for molecular apertures based on a rectangular boundary MIMO array according to an exemplary embodiment of the present invention;

[0042] Figure 2 A schematic diagram schematically illustrates an imaging scene coordinate system of a rectangular boundary array according to an exemplary embodiment of the present invention;

[0043] Figure 3 A schematic diagram schematically illustrates a process flow of a fast wavenumber domain imaging method for molecular apertures based on a rectangular boundary MIMO array according to an exemplary embodiment of the present invention;

[0044] Figure 4 A schematic diagram schematically illustrates a rectangular boundary array antenna arrangement according to an exemplary embodiment of the present invention;

[0045] Figure 5 A schematic diagram schematically illustrates a rectangular boundary array and a target position in space according to an exemplary embodiment of the present invention;

[0046] Figure 6 A schematic diagram schematically illustrating a front view of a scattered target according to an exemplary embodiment of the present invention;

[0047] Figure 7 A schematic diagram schematically illustrating a left view of a scattered target according to an exemplary embodiment of the present invention;

[0048] Figure 8 A schematic diagram schematically illustrates the projection of scattered point target imaging on the xy plane by an algorithm according to an exemplary embodiment of the present invention;

[0049] Figure 9 A schematic diagram schematically illustrates a three-dimensional image of scattered point targets imaged by an algorithm according to an exemplary embodiment of the present invention;

[0050] Figure 10 The figure schematically shows the composition of an electronic device in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0051] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0052] In addition, the accompanying drawings are merely schematic illustrations of the present invention and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0053] In related technologies, the BP algorithm requires energy accumulation from all transmitting and receiving antennas, resulting in poor real-time performance. The CS algorithm and the FS algorithm are far-field algorithms. When applied in the near field, it is difficult to reduce the approximation of the algorithm itself, resulting in poor imaging effects. The MIMO-RMA algorithm requires zero padding of the data to make the data uniform during Fourier transform. The amount of data after zero padding and Fourier transform is very large, requiring a large amount of running memory, which is difficult to implement on general hardware. In addition, the MIMO-RMA method requires interpolation operations, resulting in reduced timeliness. The SAR-FFT algorithm can convert MIMO data into several SIMO data streams for processing. When there are many transmitting antennas, the amount of SIMO data streams processed will also be relatively large, resulting in imaging that cannot meet real-time requirements.

[0054] In response to the shortcomings and deficiencies of the prior art, a fast wavenumber domain imaging method for molecular aperture based on a rectangular boundary MIMO array is provided in this example embodiment. The five-dimensional echo data of the MIMO rectangular boundary array is subjected to molecular aperture dimensionality reduction and divided into multiple sub-apertures, and the data of each sub-aperture is three-dimensional. The echo data of each sub-aperture is imaged using the wavenumber domain method, and the imaging results of each sub-aperture are accumulated to obtain the total imaging result. The amount of data for each sub-aperture is reduced by molecular aperture operation, and the imaging time is greatly reduced by using a fast wavenumber domain algorithm. The rectangular boundary MIMO array can greatly improve the imaging efficiency when imaging the target by applying the wavenumber domain method of molecular aperture.

[0055] In this example implementation, reference Figure 1 As shown, the rapid wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array may specifically include the following steps:

[0056] Step S11, receiving an echo signal for a target and preprocessing the echo signal to obtain a corresponding intermediate frequency signal;

[0057] Step S12, dividing the intermediate frequency signal based on the sub-aperture division strategy of the antenna array, and determining sub-aperture data corresponding to each sub-aperture;

[0058] Step S13, performing a Fourier transform based on a two-dimensional spatial domain on the sub-aperture data to obtain wavenumber domain data corresponding to the sub-aperture data;

[0059] Step S14: performing sub-aperture imaging on the wavenumber domain data based on Fourier transform, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging.

[0060] Hereinafter, each step of the fast wavenumber domain imaging method of a molecular aperture based on a rectangular boundary MIMO array in this exemplary embodiment will be described in more detail with reference to the accompanying drawings and embodiments.

[0061] In step S11 , an echo signal for a target is received, and the echo signal is pre-processed to obtain a corresponding intermediate frequency signal.

[0062] For example, the above imaging method can be applied to a smart terminal device, which can be connected to a MIMO antenna array to receive and process echo signals received by the antenna array in real time. For example, the smart terminal device can be a mobile phone, tablet computer, or laptop computer, which has sufficient computing power and storage space.

[0063] For example, the MIMO antenna array may be a rectangular boundary MIMO array. Figure 2 As shown, the MIMO array can be a top and bottom row of transmitting antennas and a left and right column of receiving antennas. Let the number of transmitting antennas in each row be M and the number of receiving antennas in each column be N. The position of the transmitting antenna is (x t ,y t ,z a ), the position of the receiving station antenna is (x r ,y r ,z a ), the target's range is D, and the target's position is (x, y, z).

[0064] Exemplarily, the preprocessing of the echo signal includes: performing a mixing operation and a de-skewing operation on the echo signal in sequence.

[0065] For example, the above-mentioned target can be an object in the environment when performing recognition tasks or classification tasks. The radio frequency signal transmitted by the MIMO array can be a linear frequency modulated continuous wave (LFMCW) signal; the receiving antenna of the MIMO array can receive the echo signal of the target. The received echo signal can be mixed and de-skewed to obtain the echo data of the corresponding intermediate frequency signal. The corresponding formula can be expressed as:

[0066] s(x t ,y t,x r ,y r ,k)=∫∫∫ D o(x,y,z)·exp(jkR t )·exp(jkR r )dxdydz(1)

[0067] Where o(x, y, z) is the reflection coefficient of the target at (x, y, z); k is the signal wave number, k = 2π(f0 + Kt) / c, f0 is the starting frequency, K is the frequency modulation slope, t is the fast time, and c is the speed of light; R t is the distance from the transmitting antenna to the target, R r is the distance from the receiving antenna to the target.

[0068] Specifically, R t and R r The expressions include:

[0069]

[0070] In step S12, the intermediate frequency signal is divided based on the sub-aperture division strategy of the antenna array, and sub-aperture data corresponding to each sub-aperture is determined.

[0071] Exemplarily, the method further includes: configuring a sub-aperture division strategy according to the task type and / or target type, and performing sub-aperture division on the antenna array based on the sub-aperture division strategy.

[0072] Specifically, the antenna array can be pre-divided into sub-apertures, for example, into 4, 6, or 8 sub-apertures. Alternatively, the sub-aperture division can be performed before transmitting the RF signal based on the type of task currently being performed by the antenna device, the type of environment, the imaging timeliness requirements, and / or the type of current hardware device.

[0073] For example, you can Figure 2 The antenna array shown can be symmetrically divided into four sub-apertures. For example, the first row of transmitting antennas (T1) and the first column of receiving antennas (R1) are taken as a sub-aperture. The corresponding sub-aperture echo data can be expressed as s(x t ,y t,1 ,x t,1 ,y r ,k), which is simply expressed as s(x t ,y r ,k) (1,1) The formula for the echo data of the sub-aperture (1, 1) can be expressed as:

[0074]

[0075] Among them, yt,1 Represents the y-axis coordinate of the first row of transmitting antennas, x r,1 represents the x-axis coordinate of the first column of receiving antennas. For this sub-aperture, y t,1 and x r,1 are all constants.

[0076] According to the mathematical relationship, the back reflection coefficient of the target point (x, y, z) can be expressed as:

[0077]

[0078] For example, when divided into 4 sub-apertures, the imaging results corresponding to each sub-aperture can be expressed as:

[0079]

[0080] In step S13, a Fourier transform based on a two-dimensional space domain is performed on the sub-aperture data to obtain wavenumber domain data corresponding to the sub-aperture data.

[0081] For example, For example, since |y t,1 -y| is the distance from the target to the transmitting antenna in the y direction, |x r,1 -x| is the distance from the target to the receiving antenna in the x direction. Using the paraxial approximation, |y t,1 -y|<<|z a -z|,|x r,1 -x|<<|z a -z|. Formula (4) can be written as follows after approximation and recombination:

[0082]

[0083] in, is a convolution operation. Since the coordinates of the transmitting and receiving antennas (x t ,y r ) and the target coordinates (x, y) are in the same Cartesian coordinate system, so the coordinate representations can be converted to each other, and formula (6) can be written as:

[0084]

[0085] in, Represents the convolution symbol, and in formula (7) r The integral of y r In the form of convolution, formula (7) can be expressed as:

[0086]

[0087] For simplicity, let:

[0088]

[0089] In formula (9), the phase term can be expressed as:

[0090]

[0091] Since the convolution in the spatial domain is equal to the product in the wavenumber domain, the data in the spatial domain can be converted to the wavenumber domain through Fourier transform.

[0092] In step S14, sub-aperture imaging is performed on the wavenumber domain data based on Fourier transform, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging.

[0093] Exemplarily, performing sub-aperture imaging on the wavenumber domain data based on Fourier transform, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging, includes:

[0094] Convolution processing is performed on the wavenumber domain data using a preconfigured phase factor to obtain multi-dimensional data; wherein the data dimensions of the multi-dimensional data include: a two-dimensional wavenumber domain dimension and a time domain dimension;

[0095] Performing Fourier transform on the multi-dimensional data in the time domain to obtain data to be processed that is converted into the frequency domain;

[0096] Corresponding slice data is extracted from the data to be processed, and sub-aperture imaging is generated according to the slice data, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging.

[0097] Exemplarily, the phase factor includes: a first phase factor and a second phase factor;

[0098] The convolution process is performed on the wavenumber domain data using the preconfigured phase factor to obtain multi-dimensional data, including:

[0099] Performing convolution processing on the wavenumber domain data using the first phase factor to obtain intermediate data;

[0100] The intermediate data is convolved using a second phase factor to obtain the multi-dimensional data.

[0101] Specifically, after acquiring wavenumber domain data for each subaperture, the wavenumber domain data can be convolved using phase factors G1 and G2 to generate multidimensional data. This multidimensional data can include three dimensions, namely, two wavenumber domain dimensions, and a time domain dimension. Subsequently, a Fourier transform can be performed on the multidimensional data in the time domain to obtain processed data converted from the time domain to the frequency domain. This processed data can then be used to generate slice data, and subaperture imaging can be generated based on the slice data, thereby generating a 3D imaging result using subaperture imaging.

[0102] Exemplarily, extracting corresponding data slices from the data to be processed, generating sub-aperture imaging according to the data slices, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging includes:

[0103] Based on a distance division rule preconfigured for an imaging range, slice data extraction is performed on the data to be processed to obtain slice data of a specific distance;

[0104] Perform inverse Fourier transform in the wavenumber domain on the slice data at a specific distance to obtain sub-aperture imaging in the spatial domain;

[0105] The sub-aperture images corresponding to each sub-aperture are combined and processed to obtain the full-aperture image corresponding to a specific distance;

[0106] The imaging range is sliced ​​and tomographically processed based on preconfigured distance division rules to obtain three-dimensional imaging results.

[0107] Exemplarily, performing slice tomography processing on the imaging range based on a preconfigured distance division rule to obtain a three-dimensional imaging result includes:

[0108] Traversing each specific distance based on a preconfigured distance division rule to obtain full-aperture imaging corresponding to each specific distance;

[0109] The full-aperture images corresponding to each specific distance are combined and processed to obtain a three-dimensional imaging result.

[0110] Specifically, the imaging range can be divided into distances in advance using distance division rules, so that slice data at different distances can be obtained. For example, for a sub-aperture, it can be divided into multiple distances; for a specific distance, the slice data corresponding to the specific distance is transformed to obtain the sub-aperture imaging corresponding to the sub-aperture at the specific distance. Taking the above-mentioned four sub-apertures as an example, the slice data of each sub-aperture at the current specific distance can obtain four corresponding sub-aperture imaging, and the four sub-aperture imaging are combined to obtain the full-aperture imaging at the current specific distance. For each specific distance, the corresponding full-aperture imaging can be obtained respectively, and then the full-aperture imaging of each specific distance is combined to obtain a three-dimensional imaging result.

[0111] Specifically, assuming that z s For target imaging at , the Fourier transform of each term in formula (8), formula (9) and formula (10) is:

[0112] O(k x ,k y ,z s ) (1,1) =FT x,y (o(x,y,z s )(1,1) )

[0113] S′(k x ,k y ,k) (1,1) =FT x,y (s′(x,y,k) (1,1) )

[0114] S(k x ,k y ,k) (1,1) =FT x,y (s(x,y,k) (1,1) )

[0115] G1(k x ,z s )=FT x (g1(x,z s ))

[0116] G2(k y ,z s )=FT y (g2(y,z s )) (11)

[0117] Among them, k x is the component of wave number k in the x dimension, k y is the component of wave number k in the y dimension.

[0118] Perform Fourier transform on both sides of formula (9) and substitute formula (11) into it to obtain:

[0119] S′(k x ,k y ,k) (1,1) =S(k x ,k y ,k) (1,1) ·G1(k x ,z x )·G2(k y ,z x ) (12)

[0120] Perform Fourier transform on both sides of formula (8) and substitute formula (12) to obtain:

[0121] O(k x ,k y ,z x ) (1,1) =∫S′(k x ,k y ,k) (1,1) dk (13)

[0122] In order to save the subsequent calculation operations and integration, the right side of formula (13) can be changed to S'(k x ,k y ,k) (1,1) The fast time component t of the medium wave number k is Fourier transformed to extract z s The slice at position. The formula can be expressed as:

[0123] S′(k x ,k y ,f) (1,1) =FT t (S′(k x ,k y ,k) (1,1) )…(14)

[0124] Among them, z s The frequency corresponding to the slice at position is ΔR is the distance resolution, and Δf is the frequency resolution.

[0125] After extracting the distance slice, formula (13) can be expressed as:

[0126]

[0127] Performing inverse Fourier transform on both sides of formula (15) in the two-dimensional wavenumber domain yields:

[0128]

[0129] For example, taking the above division into 4 sub-apertures as an example, for the other sub-aperture data s(x, y, k) (1,2) , s(x,y,k) (2,1) and s(x,y,k) (2,2) , using the above method to perform sub-aperture imaging respectively, the corresponding sub-aperture imaging can be obtained and expressed as: o(x, y, z s ) (1,2) ,o(x,y,z s ) (2,1) and o(x,y,z s ) (2,2) .

[0130] The data of all sub-apertures corresponding to the sub-aperture imaging results are accumulated to obtain the total full-aperture imaging result. The formula can be expressed as:

[0131] o(x,y,z s )=o(x,y,z s ) (1,1) +o(x,y,z s ) (1,2) +o(x,y,z s )(2,1) +o(x,y,z s ) (2,2) …(17)

[0132] Synchronously, the imaging range can be sliced ​​and tomographically processed to obtain full-aperture images corresponding to each distance, and the full-aperture images can be combined to obtain the most useful three-dimensional imaging results. The corresponding formula can be expressed as:

[0133] o(x,y,z)=∫ D o(x,y,z s )dz s …(18)

[0134] Exemplary, reference Figure 4 The rectangular boundary array shown in Figure 5 has two rows of transmitting antennas and two columns of receiving antennas. Each row and column has 64 antenna elements. The spacing between the antenna elements is 0.7λ, where λ is the wavelength of the RF signal. The target is set as a spatial scattered target. The position of the target and the rectangular boundary array in space is shown in Figure 5. The front view and left view of the spatial position relationship of the scattered target are shown in Figure 5. Figure 6 and Figure 7 As shown. The imaging time of this method is 0.8928s when 31 slices are uniformly taken from 45cm to 75cm. The imaging time of the BP algorithm is 18498.9642s, and the imaging time of the SAR-FFT algorithm is 443.0301s. The operation time of the imaging algorithm proposed in the present invention is much shorter than that of the BP algorithm and the SAR-FFT algorithm. The projection of the imaging result of the algorithm proposed in the present invention on the xy plane is shown as follows Figure 8 As shown, the three-dimensional view of the imaging result is as follows Figure 9 shown.

[0135] The imaging method provided by the present invention refers to Figure 3As shown, the echo data received by the antenna array can be divided into sub-aperture data corresponding to four sub-apertures. For each sub-aperture, the sub-aperture data can first be converted to the wavenumber domain to obtain wavenumber domain data, and then convolved using phase factors G1 and G2. The wavenumber domain data is then Fourier transformed in the time domain to convert the time domain data to the frequency domain, obtaining slice data at a specific distance. The two-dimensional wavenumber domain inverse Fourier transform is then converted to the spatial domain to obtain sub-aperture imaging. The sub-aperture images corresponding to the four sub-apertures are accumulated to obtain the full-aperture imaging result. All range slices are combined to perform slice tomography on the full-aperture imaging to obtain a three-dimensional imaging result. For each sub-aperture data and each specific distance, the sub-aperture imaging calculation process and the full-aperture imaging calculation process can be processed in parallel, improving data processing efficiency, shortening imaging time, meeting real-time requirements, and reducing the memory space required for electronic equipment. Furthermore, the calculation time of the imaging method of the present invention is much shorter than that of the BP algorithm and the SAR-FFT algorithm, and the calculation storage occupied is much smaller than that of the MIMO-RMA algorithm.

[0136] The method of the present invention proposes the concept of molecular aperture for rectangular boundary arrays. Considering that rectangular boundary MIMO arrays are commonly used MIMO antenna arrays, since the transmitting and receiving antennas are distributed in a two-dimensional plane, the dimensionality of the received echo data is high and the calculation is complex. The rectangular boundary MIMO array is divided into four sub-apertures according to rows and columns, and the received echo data is reduced in dimensionality. Performing imaging calculations on each sub-aperture can greatly reduce the computational complexity. Reducing the data dimensionality through molecular apertures effectively reduces the computational complexity, thereby reducing data calculation time.

[0137] Subaperture data are imaged using a fast wavenumber-domain algorithm. The subaperture imaging results are accumulated to generate the full-aperture imaging result, which is then sliced ​​in the distance dimension to produce a three-dimensional image of the target. While the molecular aperture method reduces data processing complexity, the wavenumber-domain method employed in this invention efficiently produces imaging results.

[0138] It should be noted that the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention and are not intended to be limiting. It is readily understood that the processes illustrated in the above figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0139] Furthermore, the embodiment of this example also provides a fast wavenumber domain imaging system of a molecular aperture based on a rectangular boundary MIMO array, comprising: an antenna array and an intelligent terminal connected to each other.

[0140] The antenna array can be used to transmit radio frequency signals and receive echo signals.

[0141] Smart terminals may include:

[0142] The signal receiving module is used to receive the echo signal of the target and pre-process the echo signal to obtain the corresponding intermediate frequency signal;

[0143] A sub-aperture data processing module is used to divide the intermediate frequency signal based on the sub-aperture division strategy of the antenna array and determine the sub-aperture data corresponding to each sub-aperture;

[0144] A wavenumber domain conversion module is used to perform Fourier transform based on the two-dimensional spatial domain on the sub-aperture data to obtain wavenumber domain data corresponding to the sub-aperture data;

[0145] The imaging processing module is used to perform sub-aperture imaging on the wavenumber domain data based on Fourier transform, and generate a three-dimensional imaging result of the target based on the sub-aperture imaging.

[0146] The functional implementation of each module in the imaging system has been explained in detail in the corresponding method embodiments and will not be repeated here.

[0147] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules or units described above can be concretized in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0148] Figure 10 A schematic diagram of an electronic device suitable for implementing an embodiment of the present invention is shown, where the electronic device is used to perform the above-mentioned imaging method.

[0149] It should be noted that Figure 10 The electronic device 1000 shown is only an example and should not limit the functions and scope of use of the embodiments of the present invention.

[0150] like Figure 10As shown, electronic device 1000 includes a central processing unit (CPU) 1001, which can perform various appropriate actions and processes according to the program stored in read-only memory (ROM) 1002 or the program loaded from storage portion 1008 into random access memory (RAM) 1003. Various programs and data required for system operation are also stored in RAM 1003. CPU 1001, ROM 1002 and RAM 1003 are connected to each other via bus 1004. Input / output (I / O) interface 1005 is also connected to bus 1004.

[0151] The following components are connected to the I / O interface 1005: an input section 1006 including a keyboard, a mouse, and the like; an output section 1007 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 1008 including a hard disk and the like; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card or a modem. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. Removable media 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 1010 as needed, so that computer programs read therefrom can be installed into the storage section 1008 as needed.

[0152] In particular, according to an embodiment of the present invention, the process described below with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product that includes a computer program carried on a storage medium, the computer program containing program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 1009 and / or installed from a removable medium 1011. When the computer program is executed by the central processing unit (CPU) 1001, the various functions defined in the system of the present application are performed.

[0153] Specifically, the electronic device may be an onboard electronic device, or may be a smart wearable device that cooperates with a helmet display.

[0154] It should be noted that the storage medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any storage medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code contained on the storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0155] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0156] The units involved in the embodiments of the present invention may be implemented in software or hardware, and the units described may also be provided in a processor. In some cases, the names of these units do not limit the units themselves.

[0157] It should be noted that, as another aspect, the present application also provides a storage medium, which can be included in an electronic device; or it can exist independently without being installed in the electronic device. The above storage medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements the method described in the following embodiments. For example, the electronic device can implement the following Figure 1 The individual steps of the method are shown.

[0158] In one embodiment, the present application provides a computer program product, including a computer program, which implements the steps in the above-mentioned method embodiments when executed by a processor.

[0159] Furthermore, the figures above are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention and are not intended to be limiting. It is readily understood that the processes illustrated in the figures above do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0160] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the claims.

[0161] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings and that various modifications and variations can be made without departing from the scope thereof, which is limited only by the appended claims.

Claims

1. A fast wavenumber domain imaging method for molecular apertures based on rectangular boundary MIMO arrays, characterized in that: The method comprises: Receive the echo signal of the target and pre-process the echo signal to obtain the corresponding intermediate frequency signal; The intermediate frequency signal is divided based on the sub-aperture division strategy of the antenna array, and the sub-aperture data corresponding to each sub-aperture is determined; Performing Fourier transform based on the two-dimensional spatial domain on the sub-aperture data to obtain wavenumber domain data corresponding to the sub-aperture data; Sub-aperture imaging is performed on the wavenumber domain data based on Fourier transform, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging, including: performing convolution processing on the wavenumber domain data using a preconfigured phase factor to obtain multi-dimensional data; wherein the data dimensions of the multi-dimensional data include: two-dimensional wavenumber domain dimensions and time domain dimensions; Fourier transform is performed on the multi-dimensional data in the time domain to obtain data to be processed converted to the frequency domain; corresponding slice data is extracted from the data to be processed, and sub-aperture imaging is generated according to the slice data, and a three-dimensional imaging result of the target is generated based on the sub-aperture imaging.

2. The method according to claim 1, characterized in that The pre-processing of the echo signal comprises: The echo signal is subjected to a mixing operation and a de-skewing operation in sequence.

3. The method according to claim 1, characterized in that The phase factors include: a first phase factor and a second phase factor; The convolution process is performed on the wavenumber domain data using the preconfigured phase factor to obtain multi-dimensional data, including: Performing convolution processing on the wavenumber domain data using the first phase factor to obtain intermediate data; The intermediate data is convolved using a second phase factor to obtain the multi-dimensional data.

4. The method according to claim 1, wherein Extracting corresponding data slices from the data to be processed, generating sub-aperture imaging according to the data slices, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging, including: Based on a distance division rule preconfigured for an imaging range, slice data extraction is performed on the data to be processed to obtain slice data of a specific distance; Perform inverse Fourier transform in the wavenumber domain on the slice data at a specific distance to obtain sub-aperture imaging in the spatial domain; The sub-aperture images corresponding to each sub-aperture are combined and processed to obtain the full-aperture image corresponding to a specific distance; The imaging range is sliced ​​and tomographically processed based on preconfigured distance division rules to obtain three-dimensional imaging results.

5. The method according to claim 4, characterized in that Perform slice tomography on the imaging range based on pre-configured distance division rules to obtain 3D imaging results, including: Traversing each specific distance based on a preconfigured distance division rule to obtain full-aperture imaging corresponding to each specific distance; The full-aperture images corresponding to each specific distance are combined and processed to obtain a three-dimensional imaging result.

6. The method according to claim 1, wherein The method further comprises: A sub-aperture partitioning strategy is configured according to a task type and / or a target type, and sub-aperture partitioning is performed on the antenna array based on the sub-aperture partitioning strategy.

7. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array is implemented as claimed in any one of claims 1 to 6.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array according to any one of claims 1 to 6 is implemented.

9. An electronic device, characterized in that: include: processor; as well as a memory for storing executable instructions of the processor; The processor is configured to execute the fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array according to any one of claims 1 to 6 by executing the executable instructions.

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