Rapid wave number domain imaging method of molecular aperture based on rectangular boundary MIMO array

Abstract

The invention particularly relates to a rapid wavenumber domain imaging method for molecular apertures based on a rectangular boundary MIMO array, and the method comprises the steps: receiving an echo signal for a target, and carrying out the preprocessing of the echo signal, so as to obtain a corresponding intermediate frequency signal; dividing the intermediate frequency signal based on a sub-aperture division strategy of the antenna array, and determining sub-aperture data corresponding to each sub-aperture; fourier transform based on a two-dimensional spatial domain is carried out on the sub-aperture data, and wavenumber domain data corresponding to the sub-aperture data are obtained; and performing sub-aperture imaging on the wave number domain data based on Fourier transform, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging. The method can reduce the imaging time and greatly improve the imaging efficiency.

Description

Technical Field

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

[0002] In related technologies, millimeter wave (MMW) multiple-input multiple-output (MIMO) antenna arrays have extensive applications in near-field imaging. Because millimeter waves have the characteristics of high resolution and penetrability, they have unique advantages in security inspection imaging, non-destructive testing, medical diagnosis, etc. A common MIMO antenna array is a rectangular boundary MIMO array. Due to the characteristics of large coverage range and high gain of the rectangular boundary MIMO array, the rectangular boundary array is becoming more and more popular. The imaging algorithm of the rectangular boundary MIMO array is a key step in imaging.

[0003] In existing imaging algorithms, there are still certain defects, including low effectiveness; high requirements for hardware devices, such as computing power and storage device space. For example, the Back Projection (BP) algorithm is a classic imaging algorithm. Since the BP algorithm has no approximation, the imaging quality of the BP algorithm is the highest. This algorithm forms an image through coherent accumulation, and the timeliness is very low, and it cannot be used in efficient practical applications. The Chirp Scaling (CS) algorithm and the Frequency Scaling (FS) algorithm are far-field algorithms. When they are introduced into the near field, some approximations of the algorithms themselves are still retained, so the imaging quality is low and cannot meet specific business requirements. The Range Migration Algorithm (RMA) is a classic frequency domain algorithm. The MIMO-RMA algorithm can be used for MIMO antenna arrays. The MIMO-RMA has the characteristics of good imaging quality and fast speed. However, for a large-scale antenna array such as a MIMO rectangular boundary array, the obtained echo data has 4 dimensions in the spatial dimension. During the conversion to the frequency domain, the storage space required for the echo data is extremely large, and there are high requirements for the hardware computing platform. The SAR-FFT algorithm processes MIMO data by converting it into multiple single-input multiple-output (SIMO) data. When the number of antennas is large, there are a large number of SIMO data streams to be processed, and the timeliness is low.

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

[0005] The present invention provides a fast wavenumber domain imaging method based on a molecular aperture of 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, and thus can overcome the defects existing in the prior art to a certain extent.

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

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

[0008] Receiving an echo signal for a target, and preprocessing the echo signal to obtain a corresponding intermediate frequency signal;

[0009] Dividing the intermediate frequency signal based on a sub-aperture division strategy for an antenna array to determine sub-aperture data corresponding to each sub-aperture;

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

[0011] 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.

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

[0013] Performing a mixing operation and a dechirping operation on the echo signal in sequence.

[0014] In some exemplary embodiments, the 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] Performing convolution processing on the wavenumber domain data using a pre-configured phase factor to obtain multi-dimensional data; wherein, the data dimensions of the multi-dimensional data include: two-dimensional wavenumber domain dimension, time domain dimension;

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

[0017] Extract corresponding slice data from the data to be processed, generate sub-aperture imaging based on the slice data, and generate a three-dimensional imaging result of the target based on the sub-aperture imaging.

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

[0019] The convolution processing of the wavenumber domain data using a pre-configured phase factor to obtain multi-dimensional data includes:

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

[0021] Perform convolution processing on the intermediate data using the second phase factor to obtain the multi-dimensional data.

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

[0023] Based on a pre-configured distance division rule for the imaging range, extract slice data from the data to be processed to obtain slice data at a specific distance;

[0024] Perform an 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] Perform a combination process on the sub-aperture imaging corresponding to each sub-aperture to obtain full-aperture imaging corresponding to a specific distance;

[0026] Perform slice tomography processing on the imaging range based on a pre-configured distance division rule to obtain a three-dimensional imaging result.

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

[0028] Traverse each specific distance based on a pre-configured distance division rule to obtain full-aperture imaging corresponding to each specific distance;

[0029] Perform a combination process on the full-aperture imaging corresponding to each specific distance to obtain a three-dimensional imaging result.

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

[0031] Configure a sub-aperture division strategy according to the task type and / or target type, and perform sub-aperture division on the antenna array based on the sub-aperture division strategy.

[0032] According to a second aspect of the present invention, there is provided a storage medium having stored thereon a computer program which, when executed by a processor, implements the above-mentioned fast wavenumber domain imaging method based on a rectangular boundary MIMO array with a molecular aperture.

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

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

[0035] a processor; and

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

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

[0038] The fast wavenumber domain imaging method based on a rectangular boundary MIMO array with a molecular aperture provided by the embodiments of the present invention can, by pre-dividing the antenna array into sub-apertures, determine the sub-aperture data corresponding to each sub-aperture after converting the echo signal into an intermediate frequency signal, thereby realizing dimensionality reduction of the echo data, obtaining the three-dimensional sub-aperture data corresponding to each sub-aperture, reducing the data volume of each sub-aperture, enabling parallel processing of the sub-aperture data, reducing the imaging time, and reducing the storage space requirement for hardware devices. By imaging the echo data of each sub-aperture using the wavenumber domain method, the imaging efficiency can be effectively improved and the imaging time can be reduced.

[0039] It should be understood that the above general description and the following detailed description are only exemplary and explanatory and should not limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0041] Figure 1 Schematic diagram schematically showing a fast wavenumber domain imaging method based on a rectangular boundary MIMO array with a molecular aperture according to an exemplary embodiment of the present invention;

[0042] Figure 2 Schematic diagram showing the imaging scene coordinate system of a rectangular boundary array in an exemplary embodiment of the present invention;

[0043] Figure 3 Schematic diagram showing the flowchart of a fast wavenumber domain imaging method for the molecular aperture based on a rectangular boundary MIMO array in an exemplary embodiment of the present invention;

[0044] Figure 4 Schematic diagram showing the arrangement of an antenna array with a rectangular boundary in an exemplary embodiment of the present invention;

[0045] Figure 5 Schematic diagram showing the spatial positions of a rectangular boundary array and a target in an exemplary embodiment of the present invention;

[0046] Figure 6 Schematic diagram showing the front view of a scatter target in an exemplary embodiment of the present invention;

[0047] Figure 7 Schematic diagram showing the left view of a scatter target in an exemplary embodiment of the present invention;

[0048] Figure 8 Schematic diagram showing the projection of the imaging of a scatter target on the x - y plane by the algorithm in an exemplary embodiment of the present invention;

[0049] Figure 9 Schematic diagram showing the three - dimensional image of the imaging of a scatter target by the algorithm in an exemplary embodiment of the present invention;

[0050] Figure 10 Schematic diagram showing the composition of an electronic device in an exemplary embodiment of the present invention. Detailed implementation manners

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

[0052] In addition, the attached drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0053] In the related art, the BP algorithm requires the energy accumulation of all transceiver antennas, resulting in poor real-time performance. The CS algorithm and the FS algorithm are far-field algorithms, and it is difficult to reduce the approximations inherent in the algorithms when applied in the near field, resulting in poor imaging effects. Since the MIMO-RMA algorithm needs to zero-pad the data to make the data uniform for Fourier transform, the amount of data after zero-padding and Fourier transform is very large, requiring extremely large operating memory and being difficult to implement on general hardware. Moreover, the method of MIMO-RMA requires interpolation operations, resulting in reduced timeliness. The SAR-FFT algorithm can transform MIMO data into several SIMO data streams for processing. When there are many transmitting antennas, the amount of SIMO data streams to be processed is also relatively large, resulting in imaging that cannot meet the real-time requirement.

[0054] In view of the disadvantages and deficiencies of the prior art, a fast wavenumber domain imaging method based on the molecular aperture of a rectangular boundary MIMO array is provided in the present exemplary embodiment. By reducing the dimension of the five-dimensional echo data of the MIMO rectangular boundary array into multiple sub-apertures through molecular aperture, the data of each sub-aperture is three-dimensional. The echo data of each sub-aperture is imaged by the wavenumber domain method, and the imaging results of each sub-aperture are accumulated to obtain the total imaging result. By the molecular aperture operation, the amount of data of each sub-aperture is reduced, and by using the fast wavenumber domain algorithm, the imaging time is greatly reduced. When the rectangular boundary MIMO array applies the wavenumber domain method of the molecular aperture to image the target, the imaging efficiency can be greatly improved.

[0055] In the present exemplary embodiment, referring to Figure 1 as shown, the fast wavenumber domain imaging method based on the molecular aperture of a rectangular boundary MIMO array may specifically include the following steps:

[0056] Step S11: Receive the echo signal for the target and preprocess the echo signal to obtain the corresponding intermediate frequency signal;

[0057] Step S12: Divide the intermediate frequency signal based on the sub-aperture division strategy of the antenna array to determine the sub-aperture data corresponding to each sub-aperture;

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

[0059] Step S14: 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.

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

[0061] In step S11, receive the echo signal for the target, and preprocess the echo signal to obtain the corresponding intermediate frequency signal.

[0062] Exemplarily, the above imaging method can be applied to intelligent terminal devices. The intelligent terminal device can be connected to the MIMO antenna array to receive and process the echo signal received by the antenna array in real time. For example, the intelligent terminal device can be a mobile phone, a tablet computer, or a notebook computer, etc., which are intelligent terminals with certain computing power and storage space.

[0063] Exemplarily, the MIMO antenna array can be a rectangular boundary MIMO array. Referring Figure 2 as shown, the MIMO array can have two rows of transmitting antennas on the top and bottom, and two columns of receiving antennas on the left and right. 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 antenna is (x r , y r , z a ), the range of the target is D, and the position of the target is (x, y, z).

[0064] Exemplarily, the preprocessing of the echo signal includes: successively performing a mixing operation and a dechirping operation on the echo signal.

[0065] For example, the above target can be an object in the environment when performing recognition tasks and classification tasks. The radio frequency signal transmitted by the MIMO array can be a Linear Frequency Modulation Continuous Wave (LFMCW) signal; the receiving antennas of the MIMO array can receive the echo signal of the target. The received echo signal can be subjected to mixing processing and dechirping operation 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] Wherein, o(x, y, z) is the reflection coefficient of the target at (x, y, z); k is the signal wave number, k = 2π(f 0 + Kt) / c, f 0 is the starting frequency, K is the frequency modulation slope, t is the fast time, 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, the expressions of R t and R r include:

[0069]

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

[0071] Exemplarily, the method further includes: configuring the 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, divided into 4, 6, or 8 sub-apertures. Or, it can also be based on the type of task currently executed by the antenna device, the environmental type, the imaging timeliness requirement, and / or the type of current hardware device, and perform sub-aperture division before transmitting the radio frequency signal.

[0073] For example, for Figure 2 the shown antenna array, it can be symmetrically divided into 4 sub-apertures; for example, the first row of transmitting antennas (T1) and the first column of receiving antennas (R1) are used as a sub-aperture. Correspondingly, the echo data of the sub-aperture can be expressed as s(x t , y t,1 , x t,1 , y r , k), simply denoted as s(x t , y r , k) (1,1) . Among them, the formula for the echo data of sub-aperture (1, 1) can be expressed as:

[0074]

[0075] Among them, y t,1 represents the y-axis coordinate of the first row of transmitting antennas, and 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 both constants.

[0076] According to the mathematical relationship, the backscattering coefficient of the (x, y, z) target point 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, perform a two-dimensional spatial domain Fourier transform on the sub-aperture data to obtain the wavenumber domain data corresponding to the sub-aperture data.

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

[0082]

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

[0084]

[0085] Among them, represents the convolution symbol. The integral of y r in formula (7) is also in the form of a convolution of y r , and formula (7) can be expressed as:

[0086]

[0087] For simplicity of representation, let:

[0088]

[0089] In Equation (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 transformed 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, the 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] Performing convolution processing on the wavenumber domain data using a pre-configured phase factor to obtain multi-dimensional data; wherein, the data dimensions of the multi-dimensional data include: two-dimensional wavenumber domain dimensions and a time domain dimension;

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

[0096] Extracting corresponding slice data from the data to be processed, and generating sub-aperture imaging based on the slice data, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging.

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

[0098] The performing convolution processing on the wavenumber domain data using a pre-configured phase factor to obtain multi-dimensional data includes:

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

[0100] Performing convolution processing on the intermediate data using the second phase factor to obtain the multi-dimensional data.

[0101] Specifically, after obtaining the wavenumber domain data of each sub-aperture, the wavenumber domain data can be first convolved with phase factors G1 and G2 to obtain multi-dimensional data. The multi-dimensional data can include three-dimensional data dimensions, namely two-dimensional wavenumber domain dimensions and a time domain dimension. Then, the multi-dimensional data can be Fourier-transformed in the time domain to obtain the data to be processed transformed from the time domain to the frequency domain. The data to be processed is then used to generate slice data, and sub-aperture imaging is generated based on the slice data, so that three-dimensional imaging results can be generated using the sub-aperture imaging.

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

[0103] Based on a pre-configured distance division rule for the imaging range, data slices are extracted from the data to be processed to obtain slice data at a specific distance;

[0104] The slice data at the specific distance is subjected to an inverse Fourier transform in the wavenumber domain to obtain sub-aperture imaging in the spatial domain;

[0105] The sub-aperture imaging corresponding to each sub-aperture is combined to obtain full-aperture imaging corresponding to the specific distance;

[0106] Based on the pre-configured distance division rule, slice tomography processing is performed on the imaging range to obtain three-dimensional imaging results.

[0107] Exemplarily, based on the pre-configured distance division rule, slice tomography processing is performed on the imaging range to obtain three-dimensional imaging results, including:

[0108] Based on the pre-configured distance division rule, each specific distance is traversed to obtain full-aperture imaging corresponding to each specific distance;

[0109] The full-aperture imaging corresponding to each specific distance is combined to obtain three-dimensional imaging results.

[0110] Specifically, the imaging range can be pre-divided using a distance division rule to obtain slice data at different distances. For example, for a sub-aperture, it can be divided into multiple distances; for a specific distance, based on the slice data corresponding to the specific distance, a transformation is performed to obtain the sub-aperture imaging corresponding to the sub-aperture at the specific distance. Taking the above 4 sub-apertures as an example, the slice data of each sub-aperture at the current specific distance can obtain 4 corresponding sub-aperture imagings, and the 4 sub-aperture imagings 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 imagings at each specific distance are combined to obtain three-dimensional imaging results.

[0111] Specifically, assume the target imaging at z s , the Fourier transforms of each term in formulas (8), (9), and (10) are as follows:

[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] G 1 (k x , z s ) = FT x (g 1 (x, z s ))

[0116] G 2 (k y , z s ) = FT y (g 2 (y, z s )) (11)

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

[0118] Taking the Fourier transform of both sides of formula (9) and substituting formula (11), we get:

[0119] S′(k x , k y , k) (1,1) = S(k x , k y , k) (1,1) ·G 1 (k x , z x )·G 2 (ky , z x ) (12)

[0120] Taking the Fourier transform of both sides of Equation (8) and substituting Equation (12), we get:

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

[0122] To eliminate subsequent calculation operations and integrals, we can take the Fourier transform of the fast-time component t of the wave number k in S'(k x , k y , k) (1,1) on the right side of Equation (13) and extract the slice at the z s position. The equation 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] where the frequency corresponding to the slice at the z s position is ΔR is the range resolution and Δf is the frequency resolution.

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

[0126]

[0127] Taking the inverse Fourier transform of both sides of Equation (15) in the two-dimensional wave number domain gives:

[0128]

[0129] For example, taking the above division into 4 sub-apertures as an example, for 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 separately, 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] Accumulate the data of all sub-apertures corresponding to the sub-aperture imaging results 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] Synchronous, the imaging range can be sliced and tomographically processed to obtain the full-aperture imaging corresponding to each distance, and the full-aperture images are combined to obtain the final three-dimensional imaging result. The corresponding formula can be expressed as:

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

[0134] Exemplarily, referring to the rectangular boundary array shown in Figure 4 , the upper and lower rows are transmitting antennas, and the left and right columns are receiving antennas. Each row and each column has 64 antenna elements. The spacing between the antenna elements is 0.7λ, where λ is the wavelength of the radio frequency signal. The target is set as a spatial scatter target, and the positions of the target and the rectangular boundary array in space are as shown in 5. The front view and left view of the spatial position relationship of the scatter target are as shown in Figure 6 and Figure 7 . The imaging time for uniformly taking 31 slices in the range from 45 cm to 75 cm by this method is 0.8928 s, the imaging time of the BP algorithm is 18498.9642 s, and the imaging time of the SAR-FFT algorithm is 443.0301 s. The operation time of the imaging algorithm proposed by the present invention is much less than that of the BP algorithm and the SAR-FFT algorithm. The projection of the imaging result of the algorithm proposed by the present invention on the x-y plane is as shown in Figure 8 , and the three-dimensional view of the imaging result is as shown in Figure 9 .

[0135] The imaging method provided by the present invention, referring to Figure 3As shown in the figure, the echo data received by the antenna array can be divided into sub-aperture data corresponding to four sub-apertures. For the sub-aperture data corresponding to one sub-aperture, the wavenumber domain conversion can be performed first to obtain the wavenumber domain data, and the convolution operation is carried out using the phase factors G1 and G2; the Fourier transform of the wavenumber domain data is performed in the time domain to transfer the time domain data to the frequency domain to obtain the slice data at a specific distance; then the two-dimensional inverse Fourier transform of the wavenumber domain is converted to the spatial domain to obtain the sub-aperture imaging; the sub-aperture imaging corresponding to the four sub-apertures is accumulated to obtain the full-aperture imaging result. By combining all the distance slices, tomographic slicing is performed on the full-aperture imaging to obtain the three-dimensional imaging result. For each sub-aperture data and each specific distance, the calculation process of the sub-aperture imaging and the calculation process of the full-aperture imaging can be processed in parallel, thereby improving the data processing efficiency, shortening the imaging time, meeting the real-time requirements; and reducing the space requirement for the operating memory of the electronic device. Moreover, the calculation time of the imaging method of the present invention is much less than that of the BP algorithm and the SAR-FFT algorithm, and the calculation storage occupied is much less than that of the MIMO-RMA algorithm.

[0136] The method of the present invention proposes the idea of dividing the molecular apertures of the rectangular boundary array. Considering that the rectangular boundary MIMO array is a commonly used MIMO antenna array, since the transmitting and receiving antennas are distributed in a two-dimensional plane, the dimension of the received echo data is high and the calculation is complex. The rectangular boundary MIMO array is divided into 4 sub-apertures according to rows and columns to reduce the dimension of the received echo data. Imaging calculations are performed on each sub-aperture, which can greatly reduce the operation complexity. By reducing the dimension of the data through the molecular apertures, the operation complexity is effectively reduced, thereby reducing the data operation time.

[0137] Imaging of the sub-aperture data is performed through a fast wavenumber domain algorithm. The imaging results of the sub-apertures are accumulated to obtain the imaging result of the full-aperture, and tomographic slicing is performed on the distance dimension to obtain the three-dimensional imaging result of the target. The method of molecular apertures reduces the complexity of data processing, and the wavenumber domain method in the present invention can efficiently obtain the imaging result.

[0138] It should be noted that the above-mentioned drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present invention, rather than for limiting purposes. It is easy to understand that the processes shown in the above-mentioned drawings do not indicate or limit the time sequence of these processes. Additionally, it is also easy to understand that these processes can be executed, for example, synchronously or asynchronously in multiple modules.

[0139] Furthermore, in the embodiment of the present example, a fast wavenumber domain imaging system based on the molecular apertures of a rectangular boundary MIMO array is also provided, including: an antenna array and an intelligent terminal that are interconnected.

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

[0141] The intelligent terminal may include:

[0142] A signal receiving module, configured to receive an echo signal for a target and preprocess the echo signal to obtain a corresponding intermediate frequency signal;

[0143] A sub-aperture data processing module, configured to divide the intermediate frequency signal based on a sub-aperture division strategy for an antenna array to determine sub-aperture data corresponding to each sub-aperture;

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

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

[0146] The functions of the modules in the imaging system have been elaborated 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 a device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present invention, the features and functions of the two or more modules or units described above may be embodied in one module or unit. Conversely, the features and functions of one module or unit described above may be further divided and embodied by multiple modules or units.

[0148] Figure 10 The schematic diagram of an electronic device suitable for implementing the embodiments of the present invention is shown, and the electronic device is used to execute the above imaging method.

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

[0150] Such as Figure 10As shown, the electronic device 1000 includes a Central Processing Unit (CPU) 1001, which can perform various appropriate actions and processes according to the program stored in the Read-Only Memory (ROM) 1002 or the program loaded from the storage section 1008 into the Random Access Memory (RAM) 1003. In the RAM 1003, various programs and data required for system operation are also stored. The CPU 1001, ROM 1002, and RAM 1003 are connected to each other via a bus 1004. An Input / Output (I / O) interface 1005 is also connected to the bus 1004.

[0151] The following components are connected to the I / O interface 1005: an input section 1006 including a keyboard, a mouse, etc.; an output section 1007 including such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), etc. and a speaker, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. 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 required. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as required so that a computer program read from it can be installed into the storage section 1008 as required.

[0152] Specifically, 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, which includes a computer program carried on a storage medium, and the computer program includes program codes for performing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication section 1009, and / or installed from the removable medium 1011. When the computer program is executed by the Central Processing Unit (CPU) 1001, various functions defined in the system of the present application are executed.

[0153] Specifically, the above-mentioned electronic device can be an airborne electronic device. Alternatively, the above-mentioned electronic device can also be a smart wearable device that cooperates with a head-mounted 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, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of a computer-readable storage medium 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, and this program can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, in which computer-readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any storage medium other than a computer-readable storage medium, and this storage medium can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the storage medium can be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0155] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or 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 blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0156] The units involved in the embodiments of the present invention can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not constitute a limitation to the units themselves in some cases.

[0157] It should be noted that, on the other hand, the present application also provides a storage medium, which can be included in an electronic device; or can exist alone without being assembled into 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 is caused to implement the methods described in the following embodiments. For example, the electronic device can implement the respective steps of the method as Figure 1 shown.

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

[0159] In addition, the above drawings are only schematic illustrations of the processes included in the methods according to the exemplary embodiments of the present invention, rather than for limiting purposes. It is easy to understand that the processes shown in the above drawings do not indicate or limit the chronological order of these processes. Additionally, it is also easy to understand that these processes can be executed synchronously or asynchronously in, for example, multiple modules.

[0160] Those skilled in the art will readily think of other embodiments of the present invention after considering the specification and practicing the invention herein. The present application aims to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present invention are pointed out by the claims.

[0161] It should be understood that the present invention is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only defined 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 for 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 two-dimensional space domain on the sub-aperture data to obtain wave number domain data corresponding to the sub-aperture data; Sub-aperture imaging is performed on the wave number domain data based on Fourier transform, 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 preprocessing 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 Performing sub-aperture imaging on the wave number domain data based on Fourier transform, and generating a three-dimensional imaging result of the target based on the sub-aperture imaging, including: The wave number domain data is convolved using a pre-configured phase factor to obtain multi-dimensional data; wherein the data dimensions of the multi-dimensional data include: a two-dimensional wave number domain dimension and a time domain dimension; Performing Fourier transform on the multi-dimensional data in the time domain to obtain the data to be processed converted into 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.

4. The method according to claim 3, characterized in that The phase factor includes: a first phase factor and a second phase factor; The method of performing convolution processing on the wave number domain data using the preconfigured phase factor to obtain multi-dimensional data includes: Using the first phase factor to perform convolution processing on the wave number domain data to obtain intermediate data; The intermediate data is convolved using a second phase factor to obtain the multi-dimensional data.

5. The method according to claim 3, characterized in that: 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 the distance division rule preconfigured for the 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 imaging corresponding to each sub-aperture is combined and processed to obtain the full-aperture imaging corresponding to a specific distance; The imaging range is sliced ​​and layered based on the preconfigured distance division rules to obtain three-dimensional imaging results.

6. The method according to claim 5, characterized in that Based on the pre-configured distance division rules, the imaging range is sliced ​​and sliced ​​tomographically processed 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 imaging corresponding to each specific distance is combined and processed to obtain a three-dimensional imaging result.

7. The method according to claim 1, characterized in that The method further comprises: A sub-aperture division strategy is configured according to a task type and / or a target type, and sub-aperture division is performed on the antenna array based on the sub-aperture division strategy.

8. 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 according to any one of claims 1 to 7 is implemented.

9. 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 7 is implemented.

10. An electronic device, characterized in that: include: processor; as well as A memory, configured to store executable instructions of the processor; The processor is configured to perform the fast wavenumber domain imaging method of molecular aperture based on rectangular boundary MIMO array according to any one of claims 1 to 7 by executing the executable instructions.

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