A through-wall radar imaging method, device, equipment and system

Abstract

The present invention provides a through-wall radar imaging method, device, equipment and system, the method comprising: obtaining a through-wall radar echo signal set collected by a co-located transmitting and receiving antenna at multiple observation positions; preprocessing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set; inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving to extract the echo signal of the target to be detected; constructing an image of the target to be detected according to the echo signal of the target to be detected. The present invention effectively removes the strong reflection of foreign objects such as pipes or steel bars in the wall, and enhances the through-wall radar image of the target behind the wall, thereby improving the through-wall radar imaging quality.

Description

Technical Field

[0001] The present invention relates to the technical field of through-wall radar imaging, and in particular to a through-wall radar imaging method, device, equipment and system. Background Art

[0002] Through-the-wall radar imaging is a new type of perspective imaging technology, which is widely used in urban warfare, post-disaster rescue and other fields. Common imaging technologies include infrared imaging, thermal imaging, ultrasonic detection, visible light imaging, etc. Electromagnetic waves have good penetrability and can detect and image targets behind non-transparent media.

[0003] In through-wall radar imaging, the strong clutter generated by wall reflection often overwhelms the echo signal from the stationary target behind the wall or in the building. So far, many methods have been developed to eliminate wall clutter, but these wall clutter removal methods are generally based on two assumptions: 1) the wall surface response is much stronger than the target response behind the wall; 2) there is no foreign object reflected echo in the wall. At each antenna scanning position, the wall reflection is a relatively constant signal, while the target reflection is a changing signal.

[0004] However, in practice, for many building structures, there is a layer of steel bars or utility pipes in the wall, which will also generate strong clutter. This strong interference reflection may overwhelmingly cover the echo signal from the target behind the wall. Moreover, this clutter is stronger than the target clutter and weaker than the wall clutter. On the other hand, this type of clutter also changes at each scanning position.

[0005] Therefore, currently, due to the interference of reflected clutter from the wall and foreign objects in the wall, the through-wall radar imaging quality of the target to be measured is relatively poor. Summary of the invention

[0006] Based on this, the purpose of the present invention is to provide a through-wall radar imaging method, device, equipment and system to solve the technical problem of poor quality of existing through-wall radar imaging.

[0007] A through-wall radar imaging method according to an embodiment of the present invention includes:

[0008] Obtaining a set of through-the-wall radar echo signals collected by a co-located transmitting and receiving antenna at multiple observation locations;

[0009] Preprocessing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set, wherein the echo signal of the static background of the fixed wall includes the echo signal of the outer wall surface and the echo signal of the inner wall surface;

[0010] Inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the preprocessed through-wall radar echo signal set;

[0011] An image of the target to be detected is constructed according to the echo signal of the target to be detected.

[0012] In addition, a through-wall radar imaging method according to the above embodiment of the present invention may also have the following additional technical features:

[0013] Furthermore, the step of preprocessing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set includes:

[0014] The through-the-wall radar echo signal set is preprocessed by a two-dimensional high-pass filter to remove the echo signal of the static background of the fixed wall in the through-the-wall radar echo signal set.

[0015] Furthermore, the step of inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the preset low-rank sparse optimization algorithm for solving includes:

[0016] According to the idea of ​​low-rank sparse decomposition, the preprocessed through-wall radar echo signal set is decomposed into a low-rank part and a sparse part, the low-rank part is the echo signal of the foreign object in the wall, and the sparse part is the echo signal of the target to be detected;

[0017] Based on the low-rank part and the sparse part, a low-rank matrix L and a sparse matrix S are constructed respectively;

[0018] The low-rank matrix L, the sparse matrix S and the preset tuning parameter λ are input into the low-rank sparse optimization algorithm for solution.

[0019] Furthermore, the expression of the low-rank sparse optimization algorithm is:

[0020]

[0021] In the formula, ‖L‖ * represents the nuclear norm of the low-rank matrix L, which is the sum of the singular values ​​of the low-rank matrix L, and ‖S‖ 1 l represents the sparse matrix S 1 norm, λ is a preset tuning parameter used to balance the nuclear norm term and l 1 Norm term.

[0022] Furthermore, the step of inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the preset low-rank sparse optimization algorithm for solving includes:

[0023] The preprocessed through-wall radar echo signal set and the preset tuning parameters are input into the low-rank sparse optimization algorithm and solved with the aid of a convex optimization toolbox.

[0024] Furthermore, before the step of obtaining a through-wall radar echo signal set collected by a co-located transmitting and receiving antenna at a plurality of observation positions, the method further includes:

[0025] The co-located transmitting and receiving antenna is controlled to evenly step forward from left to right in a direction parallel to the wall, so that the co-located transmitting and receiving antenna collects through-wall radar echo signals at multiple observation positions respectively.

[0026] A through-wall radar imaging device according to an embodiment of the present invention includes:

[0027] A signal acquisition module is used to acquire a set of through-wall radar echo signals collected by a co-located transmitting and receiving antenna at multiple observation locations;

[0028] A signal pre-processing module, used for pre-processing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set, wherein the echo signal of the static background of the fixed wall includes the echo signal of the outer wall surface and the echo signal of the inner wall surface;

[0029] A signal post-processing module, used for inputting the pre-processed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the pre-processed through-wall radar echo signal set;

[0030] The image reconstruction module is used to construct an image of the target to be detected according to the echo signal of the target to be detected.

[0031] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned through-wall radar imaging method is implemented.

[0032] The present invention also proposes a through-wall radar imaging device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned through-wall radar imaging method when executing the program.

[0033] The present invention also provides a through-wall radar imaging system, the system comprising:

[0034] Through-the-wall radar imaging equipment as described above; and

[0035] The co-located transmitting and receiving antenna is connected to the through-wall radar imaging device, and the co-located transmitting and receiving antenna can evenly step forward from left to right in a direction parallel to the wall.

[0036] Compared with the existing technology: by preprocessing the through-wall radar echo signal set, the clutter signal of the static background of the fixed wall is first removed, and then the relevant low-rank features of foreign objects such as steel bars or pipes in the wall and the spatial sparse features of the target to be measured are used to model the clutter suppression of foreign objects in the wall and the signal enhancement of the target behind the wall as a low-rank sparse representation problem, thereby effectively removing the strong reflection of foreign objects such as pipes or steel bars in the wall, and enhancing the through-wall radar image of the target behind the wall, thereby improving the through-wall radar imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of a through-wall radar imaging method in a first embodiment of the present invention;

[0038] Figure 2 A diagram of a radar detection system provided by an embodiment of the present invention;

[0039] Figure 3 A composition diagram of reflected echoes received by a radar detection system provided by an embodiment of the present invention;

[0040] Figure 4 Echo data received by the radar provided in an embodiment of the present invention;

[0041] Figure 5 A cross-sectional diagram of a system scenario provided by an embodiment of the present invention;

[0042] Figure 6 A result diagram of image reconstruction of a target to be detected provided by an embodiment of the present invention;

[0043] Figure 7 is a flow chart of a through-wall radar imaging method in a second embodiment of the present invention;

[0044] Figure 8 is a schematic structural diagram of a through-wall radar imaging device in a third embodiment of the present invention;

[0045] Fig. 9 Schematic diagram of the structure of a through-wall radar imaging device in a fourth embodiment of the present invention.

[0046] The following specific implementations will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0048] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0050] Embodiment 1

[0051] See also Figure 1 , which shows a through-wall radar imaging method in a first embodiment of the present invention, and the method specifically includes steps S01-S04.

[0052] Step S01, obtaining a set of through-wall radar echo signals collected by a co-located transmitting and receiving antenna at multiple observation positions.

[0053] like Figure 2 As shown, in a specific implementation, the co-located transmitting and receiving antennas can be made to evenly step forward from left to right in a direction parallel to the wall, and there are a total of N antenna observation positions in the measurement direction. Figure 3 As shown in the figure, when there are abnormal media such as steel bars or pipes in the wall, the receiving antenna will collect four types of echo signals, namely:

[0054] 1) Echo signal from the exterior wall surface;

[0055] 2) Echo signals from abnormal media such as steel bars or pipes in the wall;

[0056] 3) echo signals from the inner wall surface; and

[0057] 4) Echo signals from the target to be measured. Generally speaking, in the through-wall radar system model, the wall is a horizontally uniform layer, so the echo signals on the outer wall surface and the inner wall surface are both echo signals of the static background of the fixed wall, and abnormal media such as steel bars or pipes in the wall are collectively referred to as foreign objects in the wall.

[0058] Based on the above description, the signal collected by the Nth antenna observation position can be modeled as:

[0059] z n (t) = w n(t)+l n (t)+s n (t)

[0060] Among them, w n (t) is the echo signal of the static background of the fixed wall, l n (t) is the echo signal generated by foreign objects such as steel bars or pipes in the wall (a strong clutter signal), which can be regarded as a related background signal. n (t) is the echo signal of the target to be detected. For example, see Figure 4 , which shows the radar system receiving the signal containing w n (t), l n (t) and s n (t) Echo data of three different signals.

[0061] By way of example and not limitation, in this embodiment, there are N=43 antenna positions in the measurement direction. The detection space size of this system is 1m×1m, the wall thickness is 0.12m, the center frequency is 1.5Ghz, the bandwidth is 1Ghz, and the antenna scanning step is 0.02m. The detection target is placed at 0.4m in the range direction and 0.5m in the azimuth direction in the space scene.

[0062] Step S02, preprocessing the through-wall radar echo signal set to remove the echo signal of the fixed wall static background in the through-wall radar echo signal set, wherein the echo signal of the fixed wall static background includes the echo signal of the outer wall surface and the echo signal of the inner wall surface.

[0063] That is, after the preprocessing in step S02, the signal model of the preprocessed through-wall radar echo signal set can be expressed as:

[0064] x n (t) = l n (t)+s n (t)

[0065] Step S03, inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the preprocessed through-wall radar echo signal set.

[0066] Specifically, the radar signal is sampled at each scanning position, and the number of sample collections is M. Then x n (t), l n (t), s n (t) can be expressed as an M×1 vector. After integrating the data of all N scanning positions, the following M×N data matrix can be obtained:

[0067] X=[x1 ,x 2 ,x 3 ,...,x N ]

[0068] L=[l 1 ,l 2 ,l 3 ,...,l N ]

[0069] S=[s 1 ,s 2 ,s 3 ,...,s N ]

[0070] Since L contains relevant background signals, the rank of the L matrix is ​​relatively low. For the target data matrix S, since the target features are spatially sparse, S is a sparse matrix. Therefore, the data matrix X can be represented as the superposition of the sparse matrix S and the low-rank matrix L. Therefore, the optimization problem of low-rank sparse representation can be established:

[0071]

[0072] Among them, ‖L‖ * represents the nuclear norm, which is the sum of the singular values ​​of L, and ‖S‖ 1 Indicates l 1 The tuning parameter λ is used to balance the nuclear norm term and l 1 Norm term.

[0073] By way of example and not limitation, in this system, the number of samples collected is M=637, x n (t), l n (t), s n (t) can be expressed as a 637×1 vector, and X, L, and S are all matrices of 637×43. Through mathematical analysis, it can be obtained that for a matrix of M×N dimensions, the tuning parameters is the best choice. Then the above optimization problem can be expressed as

[0074]

[0075] Therefore, in the present invention, the value of λ is λ=0.0396.

[0076] Step S04: constructing an image of the target to be detected according to the echo signal of the target to be detected.

[0077] That is, by inputting the preprocessed radar echo data X and the tuning parameter λ, the above problem is solved with the help of the convex optimization toolbox, and the matrix S can be extracted to obtain the target detection behind the wall. Figure 5 is a cross-sectional diagram of the system scenario. Figure 6 As the image result after solution, we can obtain the image reconstruction with a target at a position of 0.4m in the range direction and 0.5m in the azimuth direction.

[0078] In summary, the through-wall radar imaging method in the above-mentioned embodiment of the present invention pre-processes the through-wall radar echo signal set to first remove the clutter signal of the static background of the fixed wall, and then uses the relevant low-rank features of foreign objects such as steel bars or pipes in the wall and the spatial sparse features of the target to be measured to model the clutter suppression of foreign objects in the wall and the signal enhancement of the target behind the wall as a low-rank sparse representation problem, thereby effectively removing the strong reflection of foreign objects such as pipes or steel bars in the wall, and enhancing the through-wall radar image of the target behind the wall, thereby improving the through-wall radar imaging quality.

[0079] Embodiment 2

[0080] See also Figure 7 , which shows a through-wall radar imaging method in a second embodiment of the present invention, and the method specifically includes steps S11 to S17.

[0081] Step S11, controlling the co-located transmitting and receiving antenna to evenly step forward from left to right in a direction parallel to the wall, so that the co-located transmitting and receiving antenna collects through-wall radar echo signals at multiple observation positions respectively.

[0082] Step S12, obtaining a set of through-wall radar echo signals collected by the co-located transmitting and receiving antennas at multiple observation positions.

[0083] Step S13, preprocessing the through-wall radar echo signal set through a two-dimensional high-pass filter to remove the echo signal of the fixed wall static background in the through-wall radar echo signal set, wherein the echo signal of the fixed wall static background includes the echo signal of the outer wall surface and the echo signal of the inner wall surface.

[0084] Step S14, according to the idea of ​​low-rank sparse decomposition, decompose the preprocessed through-wall radar echo signal set into a low-rank part and a sparse part, the low-rank part is the echo signal of the foreign object in the wall, and the sparse part is the echo signal of the target to be detected.

[0085] Step S15, constructing a low-rank matrix L and a sparse matrix S based on the low-rank part and the sparse part respectively.

[0086] Step S16, input the low-rank matrix L and the sparse matrix S and the preset tuning parameter γ into the low-rank sparse optimization algorithm, and solve them with the help of the convex optimization toolbox to extract the echo signal of the target to be detected from the preprocessed through-wall radar echo signal set.

[0087] Among them, the expression of the low-rank sparse optimization algorithm is:

[0088]

[0089] In the formula, ‖L‖ * represents the nuclear norm of the low-rank matrix L, which is the sum of the singular values ​​of the low-rank matrix L, and ‖S‖ 1 l represents the sparse matrix S 1 norm, λ is a preset tuning parameter used to balance the nuclear norm term and l 1 Norm term.

[0090] That is, in the specific implementation, in the process of solving the optimization problem, based on the idea of ​​low-rank sparse decomposition, the pre-processed through-wall radar echo signal set will be automatically decomposed into a low-rank part and a sparse part. Since the echo signals generated by foreign objects such as steel bars or pipes in the wall are regarded as related background signals, the rank of this part of the signal is relatively low and is regarded as a low-rank part, and the echo signals of the target to be detected are spatially sparse, so this part of the signal is regarded as a sparse part; then, based on the low-rank part and the sparse part, a low-rank matrix L and a sparse matrix S are constructed respectively. Next, a low-rank sparse optimization algorithm is needed to perform optimization solution. The purpose of the optimization solution is to suppress the low-rank matrix L and enhance the sparse matrix S, so that after the optimization solution, the enhanced sparse matrix S with less interference from the low-rank matrix L can be extracted, so as to extract the echo signal of the target to be detected with high quality.

[0091] Step S17: constructing an image of the target to be detected according to the echo signal of the target to be detected.

[0092] Embodiment 3

[0093] Another aspect of the present invention is to provide a through-wall radar imaging device. Figure 8 , which shows a through-wall radar imaging device in a third embodiment of the present invention, and the through-wall radar imaging device comprises:

[0094] The signal acquisition module 11 is used to acquire a set of through-wall radar echo signals collected by a co-located transmitting and receiving antenna at multiple observation positions;

[0095] A signal pre-processing module 12 is used to pre-process the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set, wherein the echo signal of the static background of the fixed wall includes the echo signal of the outer wall surface and the echo signal of the inner wall surface;

[0096] A signal post-processing module 13 is used to input the pre-processed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the pre-processed through-wall radar echo signal set;

[0097] The image reconstruction module 14 is used to construct an image of the target to be detected according to the echo signal of the target to be detected.

[0098] Furthermore, in some optional embodiments of the present invention, the signal pre-processing module 12 is also used to pre-process the through-wall radar echo signal set through a two-dimensional high-pass filter to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set.

[0099] Furthermore, in some optional embodiments of the present invention, the signal post-processing module 13 is also used to decompose the pre-processed through-wall radar echo signal set into a low-rank part and a sparse part according to the idea of ​​low-rank sparse decomposition, the low-rank part being the echo signal of foreign objects in the wall, and the sparse part being the echo signal of the target to be detected; constructing a low-rank matrix L and a sparse matrix S based on the low-rank part and the sparse part respectively; inputting the low-rank matrix L, the sparse matrix S and the preset tuning parameter λ into the low-rank sparse optimization algorithm for solution.

[0100] Furthermore, in some optional embodiments of the present invention, the expression of the low-rank sparse optimization algorithm is:

[0101]

[0102] In the formula, ‖L‖ * represents the nuclear norm of the low-rank matrix L, which is the sum of the singular values ​​of the low-rank matrix L, and ‖S‖ 1 l represents the sparse matrix S 1 norm, λ is a preset tuning parameter used to balance the nuclear norm term and l 1 Norm term.

[0103] Furthermore, in some optional embodiments of the present invention, the signal post-processing module 13 is also used to input the pre-processed through-wall radar echo signal set and the preset tuning parameters into the low-rank sparse optimization algorithm, and solve them with the help of a convex optimization toolbox.

[0104] Furthermore, in some optional embodiments of the present invention, the through-wall radar imaging device further includes:

[0105] The antenna control module is used to control the co-located transmitting and receiving antenna to evenly step forward from left to right in a direction parallel to the wall, so that the co-located transmitting and receiving antenna can respectively collect through-wall radar echo signals at multiple observation positions.

[0106] The functions or operation steps implemented when the above modules and units are executed are generally the same as those in the above method embodiments, and will not be repeated here.

[0107] In summary, the through-wall radar imaging device in the above-mentioned embodiment of the present invention pre-processes the through-wall radar echo signal set to first remove the clutter signal of the static background of the fixed wall, and then uses the relevant low-rank features of foreign objects such as steel bars or pipes in the wall and the spatial sparse features of the target to be measured to model the clutter suppression of foreign objects in the wall and the signal enhancement of the target behind the wall as a low-rank sparse representation problem, thereby effectively removing the strong reflection of foreign objects such as pipes or steel bars in the wall, and enhancing the through-wall radar image of the target behind the wall, thereby improving the through-wall radar imaging quality.

[0108] Embodiment 4

[0109] Another aspect of the present invention is to provide a through-wall radar imaging device, see Fig. 9 , shown is a through-wall radar imaging device according to a fourth embodiment of the present invention, comprising a memory 20, a processor 10, and a computer program 30 stored in the memory and executable on the processor, wherein the processor 10 implements the through-wall radar imaging method as described above when executing the computer program 30.

[0110] In some embodiments, the processor 10 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor or other data processing chip, used to run program codes or process data stored in the memory 20, such as executing access restriction programs.

[0111] Among them, the memory 20 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. The memory 20 can be an internal storage unit of the through-wall radar imaging device in some embodiments, such as a hard disk of the through-wall radar imaging device. The memory 20 can also be an external storage device of the through-wall radar imaging device in other embodiments, such as a plug-in hard disk equipped on the through-wall radar imaging device, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. Further, the memory 20 can also include both an internal storage unit and an external storage device of the through-wall radar imaging device. The memory 20 can be used not only to store application software and various types of data installed in the through-wall radar imaging device, but also to temporarily store data that has been output or is to be output.

[0112] It should be pointed out that Fig. 9 The structure shown does not constitute a limitation on the through-the-wall radar imaging device. In other embodiments, the through-the-wall radar imaging device may include fewer or more components than those shown in the figure, or may combine certain components, or arrange the components differently.

[0113] In summary, the through-wall radar imaging device in the above-mentioned embodiment of the present invention pre-processes the through-wall radar echo signal set to first remove the clutter signal of the static background of the fixed wall, and then uses the relevant low-rank features of foreign objects such as steel bars or pipes in the wall and the spatial sparse features of the target to be measured to model the clutter suppression of foreign objects in the wall and the signal enhancement of the target behind the wall as a low-rank sparse representation problem, thereby effectively removing the strong reflection of foreign objects such as pipes or steel bars in the wall, and enhancing the through-wall radar image of the target behind the wall, thereby improving the through-wall radar imaging quality.

[0114] Embodiment 5

[0115] A fifth embodiment of the present invention provides a through-wall radar imaging system, the system comprising:

[0116] The through-wall radar imaging device described in the fourth embodiment above; and

[0117] The co-located transmitting and receiving antenna is connected to the through-wall radar imaging device, and the co-located transmitting and receiving antenna can evenly step forward from left to right in a direction parallel to the wall.

[0118] The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the through-wall radar imaging method as described above is implemented.

[0119] Those skilled in the art will appreciate that the logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable storage medium for use by an instruction execution system, device, or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device, or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices, or apparatuses. For purposes of this specification, a "computer-readable storage medium" may be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system, device, or apparatus, or in conjunction with such instruction execution systems, devices, or apparatuses.

[0120] More specific examples of computer-readable storage media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or processing in another suitable manner as necessary, and then stored in a computer memory.

[0121] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0122] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0123] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A through-wall radar imaging method, characterized in that: The method comprises: Obtain a set of through-the-wall radar echo signals collected at multiple observation positions by a co-located transmitting and receiving antenna that uniformly steps forward in a direction parallel to the wall, wherein the through-the-wall radar echo signals include echo signals from the outer wall surface, echo signals from abnormal media such as steel bars or pipes in the wall, echo signals from the inner wall surface, and echo signals from the target to be measured; Preprocessing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set, wherein the echo signal of the static background of the fixed wall includes the echo signal of the outer wall surface and the echo signal of the inner wall surface; Inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the preprocessed through-wall radar echo signal set; constructing an image of the target to be detected according to the echo signal of the target to be detected; The steps of inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the preset low-rank sparse optimization algorithm for solving include: According to the idea of ​​low-rank sparse decomposition, the preprocessed through-wall radar echo signal set is decomposed into a low-rank part and a sparse part, the low-rank part is the echo signal of the foreign object in the wall, and the sparse part is the echo signal of the target to be detected; Construct low-rank matrices based on the low-rank part and the sparse part respectively L and sparse matrices S； The low-rank matrix L and sparse matrices S and preset tuning parameters Input into the low-rank sparse optimization algorithm for solution.

2. The through-wall radar imaging method according to claim 1, characterized in that: The step of preprocessing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set includes: The through-the-wall radar echo signal set is preprocessed by a two-dimensional high-pass filter to remove the echo signal of the static background of the fixed wall in the through-the-wall radar echo signal set.

3. The through-wall radar imaging method according to claim 1, characterized in that: The expression of the low-rank sparse optimization algorithm is: ； In the formula, X represents the preprocessed through-wall radar echo data matrix, Represents a low-rank matrix L The nuclear norm of is a low-rank matrix L The sum of the singular values, and Represents a sparse matrix S of norm, λ is the preset tuning parameter used to balance the nuclear norm term and Norm term.

4. The through-wall radar imaging method according to claim 1, characterized in that: The steps of inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the preset low-rank sparse optimization algorithm for solving include: The preprocessed through-wall radar echo signal set and the preset tuning parameters are input into the low-rank sparse optimization algorithm and solved with the aid of a convex optimization toolbox.

5. The through-wall radar imaging method according to any one of claims 1 to 4, characterized in that: Before the step of obtaining a through-wall radar echo signal set collected by a co-located transmitting and receiving antenna at multiple observation positions, the step further includes: The co-located transmitting and receiving antenna is controlled to evenly step forward from left to right in a direction parallel to the wall, so that the co-located transmitting and receiving antenna collects through-wall radar echo signals at multiple observation positions respectively.

6. A through-wall radar imaging device, characterized in that: Used to implement the through-wall radar imaging method according to any one of claims 1 to 5, the device comprises: A signal acquisition module is used to acquire a set of through-wall radar echo signals collected by a co-located transmitting and receiving antenna at multiple observation locations; A signal pre-processing module, used for pre-processing the through-wall radar echo signal set to remove the echo signal of the static background of the fixed wall in the through-wall radar echo signal set, wherein the echo signal of the static background of the fixed wall includes the echo signal of the outer wall surface and the echo signal of the inner wall surface; A signal post-processing module, used for inputting the pre-processed through-wall radar echo signal set and the preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract the echo signal of the target to be detected from the pre-processed through-wall radar echo signal set; The image reconstruction module is used to construct an image of the target to be detected according to the echo signal of the target to be detected.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the through-wall radar imaging method as described in any one of claims 1 to 5 is implemented.

8. A through-wall radar imaging device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the through-wall radar imaging method according to any one of claims 1 to 5 is implemented.

9. A through-wall radar imaging system, characterized in that: The system comprises: The through-wall radar imaging device as claimed in claim 8; and The co-located transmitting and receiving antenna is connected to the through-wall radar imaging device, and the co-located transmitting and receiving antenna can evenly step forward from left to right in a direction parallel to the wall.

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