CN114002671A - Through-wall radar imaging method, device, equipment and system - Google Patents
Through-wall radar imaging method, device, equipment and system Download PDFInfo
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
- G01S13/888—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons through wall detection
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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Abstract
The invention provides a through-wall radar imaging method, a device, equipment and a system, wherein the method comprises the following steps: acquiring a through-wall radar echo signal set acquired by a transmitting-receiving co-located antenna at a plurality of observation position points; preprocessing the through-wall radar echo signal set to remove echo signals of a fixed wall static background in the through-wall radar echo signal set; inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving so as to extract an echo signal of a target to be detected; and constructing an image of the target to be detected according to the echo signal of the target to be detected. The invention effectively removes strong reflection of foreign matters such as pipelines or reinforcing steel bars in the wall body, enhances the through-wall radar image of the target behind the wall and improves the imaging quality of the through-wall radar.
Description
Technical Field
The invention relates to the technical field of through-wall radar imaging, in particular to a through-wall radar imaging method, device, equipment and system.
Background
Through-wall radar imaging is a novel perspective imaging technology, and is widely applied to the fields of urban battles, post-disaster rescue and the like, and common imaging technologies comprise infrared imaging, thermal imaging, ultrasonic detection, visible light imaging and the like. The electromagnetic wave has good penetrability, so that the electromagnetic wave can detect and image a target behind a non-transparent medium.
In through-wall radar imaging, strong clutter due to wall reflections tends to overwhelm echo signals from stationary targets behind walls or inside buildings, and many methods have been developed to eliminate wall clutter, but these wall clutter removal methods are generally based on two assumptions: 1) the wall response is far stronger than the target response behind the wall; 2) there is no foreign body reflection echo in the wall, and at each antenna scanning position, the wall reflection is a relatively constant signal, and the target reflection is a varying signal.
However, in practice for many building structures there is a layer of foreign matter such as reinforcing steel or utility pipes within the wall, which also generates strong noise. This strong disturbing reflection may overwhelmingly mask the echo signal from the target under test behind the wall. Moreover, the clutter is stronger than the target clutter and weaker than the wall clutter. On the other hand, such clutter is also variable at each scan position.
Therefore, the through-wall radar imaging quality of the target to be detected is relatively poor due to interference of reflected noise of foreign matters on the wall surface and in the wall at present.
Disclosure of Invention
Based on this, the invention aims to provide a through-wall radar imaging method, a through-wall radar imaging device, through-wall radar imaging equipment and a through-wall radar imaging system, so as to solve the technical problem of poor imaging quality of the existing through-wall radar.
According to the embodiment of the invention, the through-wall radar imaging method comprises the following steps:
acquiring a through-wall radar echo signal set acquired by a transmitting-receiving co-located antenna at a plurality of observation position points;
preprocessing the through-wall radar echo signal set to remove echo signals of a fixed wall static background in the through-wall radar echo signal set, wherein the echo signals of the fixed wall static background comprise echo signals of the surface of an outer wall and echo signals of the surface of an inner wall;
inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving so as to extract an echo signal of a target to be detected from the preprocessed through-wall radar echo signal set;
and constructing an image of the target to be detected according to the echo signal of the target to be detected.
In addition, the through-wall radar imaging method according to the above embodiment of the present invention may further have the following additional technical features:
further, the step of preprocessing the through-wall radar echo signal set to remove an echo signal of a fixed wall static background in the through-wall radar echo signal set includes:
and preprocessing the through-wall radar echo signal set through a two-dimensional high-pass filter so as to remove echo signals of a static background of a fixed wall body in the through-wall radar echo signal set.
Further, the step of inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving comprises:
decomposing the preprocessed through-wall radar echo signal set into a low-rank part and a sparse part according to the idea of low-rank sparse decomposition, wherein the low-rank part is an echo signal of foreign matters in a wall body, and the sparse part is an echo signal of a target to be detected;
respectively constructing a low-rank matrix L and a sparse matrix S based on the low-rank part and the sparse part;
and inputting the low-rank matrix L, the sparse matrix S and the preset tuning parameter lambda into a low-rank sparse optimization algorithm for solving.
Further, the expression of the low-rank sparse optimization algorithm is as follows:
in the formula, | L |*Representing the kernel norm of the low-rank matrix L, is the sum of the singular values of the low-rank matrix L, and | S | |)1L representing the sparse matrix S1Norm, λ is a preset tuning parameter for balancing the kernel norm term and l1A norm term.
Further, the step of inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving comprises:
and inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the low-rank sparse optimization algorithm, and solving by means of a convex optimization tool box.
Further, before the step of obtaining the through-wall radar echo signal set collected by the transceiving co-located antenna at the plurality of observation location points, the method further comprises:
and controlling the receiving and transmitting co-located antenna to uniformly step forward from left to right along the direction parallel to the wall body so as to enable the receiving and transmitting co-located antenna to respectively collect through-wall radar echo signals at the plurality of observation position points.
According to the embodiment of the invention, the through-wall radar imaging device comprises:
the signal acquisition module is used for acquiring a through-wall radar echo signal set acquired by the transceiving co-located antenna at a plurality of observation position points;
the signal preprocessing module is used for preprocessing the through-wall radar echo signal set to remove echo signals of a fixed wall static background in the through-wall radar echo signal set, wherein the echo signals of the fixed wall static background comprise echo signals of the surface of an outer wall and echo signals of the surface of an inner wall;
the signal post-processing module is used for inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving so as to extract an echo signal of a target to be detected from the preprocessed through-wall radar echo signal set;
and the image reconstruction module is used for constructing an image of the target to be detected according to the echo signal of the target to be detected.
The invention also proposes a computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, implements the above-mentioned through-wall radar imaging method.
The invention also provides a through-wall radar imaging device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor executes the program to realize the through-wall radar imaging method.
The invention also provides a through-wall radar imaging system, which comprises:
the through-wall radar imaging device as described above; and
and the transmitting and receiving co-located antenna is connected with the through-wall radar imaging equipment and can uniformly step forward from left to right along the direction parallel to the wall body.
Compared with the prior art: through preprocessing a through-wall radar echo signal set, clutter signals of a static background of a fixed wall body are removed firstly, then related low-rank characteristics of foreign matters such as reinforcing steel bars or pipelines in the wall body and space sparse characteristics of a target to be detected are utilized, the clutter suppression problem of the foreign matters existing in the wall body and the behind-wall target signal enhancement problem are modeled into a low-rank sparse representation problem, so that strong reflection of the foreign matters such as pipelines or reinforcing steel bars in the wall body is effectively removed, a through-wall radar image of the behind-wall target is enhanced, and the imaging quality of the through-wall radar is improved.
Drawings
FIG. 1 is a flow chart of a through-wall radar imaging method according to a first embodiment of the present invention;
FIG. 2 is a diagram of a radar detection system provided by an embodiment of the present invention;
FIG. 3 is a composition diagram of a reflected echo received by a radar detection system according to an embodiment of the present invention;
FIG. 4 is an echo data received by a radar according to an embodiment of the present invention;
FIG. 5 is a cross-sectional view of a system scenario provided by an embodiment of the invention;
fig. 6 is a result diagram of image reconstruction of an object to be detected according to an embodiment of the present invention;
FIG. 7 is a flowchart of a through-wall radar imaging method according to a second embodiment of the present invention;
fig. 8 is a schematic structural diagram of a through-wall radar imaging device according to a third embodiment of the present invention;
fig. 9 is a schematic structural diagram of a through-wall radar imaging device in a fourth embodiment of the present invention.
The following detailed description will further illustrate the invention in conjunction with the above-described figures.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Several embodiments of the invention are presented in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Example one
Referring to fig. 1, a through-wall radar imaging method according to a first embodiment of the present invention is shown, and the method specifically includes steps S01-S04.
And step S01, acquiring a through-wall radar echo signal set acquired by the transceiving co-located antenna at a plurality of observation position points.
As shown in fig. 2, in the specific implementation, the transmitting and receiving antenna can be made to uniformly step forward from left to right along the direction parallel to the wall, and there are N antenna observation position points in the measurement direction. As shown in fig. 3, under the condition that abnormal media such as steel bars or pipelines exist in the wall, four types of echo signals are collected by the receiving antenna, which are:
1) echo signals from the surface of the outer wall;
2) echo signals from abnormal media such as steel bars or pipelines in the wall;
3) echo signals from the surface of the interior wall; and
4) and echo signals from the target to be measured. Generally, in a through-wall radar system model, a wall is a transverse uniform layer, so that echo signals of an outer wall surface and echo signals of an inner wall surface are echo signals of a fixed wall static background, and abnormal media such as steel bars or pipelines in the wall are collectively called as foreign matters in the wall.
Based on the above description, the signal collected at the nth antenna observation position can be modeled as:
zn(t)＝wn(t)+ln(t)+sn(t)
wherein, wn(t) echo signal of static background of fixed wall,/n(t) is an echo signal (belonging to a strong clutter signal) generated by foreign matters such as steel bars or pipelines in the wall body, and can be regarded as a related background signal snAnd (t) is an echo signal of the target to be detected. For example, referring to FIG. 4, a radar system is shown receiving a signal comprising wn(t)、ln(t) and sn(t) echo data of three different signals.
By way of example and not limitation, in the present embodiment, there are N-43 antenna positions in the measurement direction. The size of a detection space of the system is 1m multiplied by 1m, the thickness of a wall body is 0.12m, the center frequency is 1.5Ghz, the bandwidth is 1Ghz, and the scanning step of an antenna is 0.02 m. The detection target is placed at a position with a distance direction of 0.4m and an azimuth direction of 0.5m in a space scene.
Step S02, preprocessing the through-wall radar echo signal set to remove an echo signal of a fixed wall static background in the through-wall radar echo signal set, where the echo signal of the fixed wall static background includes an echo signal of an outer wall surface and an echo signal of an inner wall surface.
That is, after the preprocessing in step S02, the signal model of the preprocessed through-wall radar echo signal set can be expressed as:
xn(t)＝ln(t)+sn(t)
and step S03, inputting the preprocessed through-wall radar echo signal set and 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.
Specifically, sample collection is carried out on the acquired radar signals at each scanning position, the number of the sample collection is M, and then x is carried outn(t)、ln(t)、sn(t) can all be expressed as an M × 1 vector, and after integrating the data of all N scan positions, the following M × N data matrix can be obtained:
X＝[x1，x2，x3，…，xN]
L＝[l1，l2，l3，...，lN]
S＝[s1，s2，s3，...，sN]
since L contains the relevant background signal, the rank of the L matrix is relatively low, and for the data matrix S of the target, since the target feature has spatial sparsity, S is a sparse matrix, and the data matrix X can be represented as a superposition of the sparse matrix S and the low-rank matrix L. An optimization problem of low rank sparse representation can thus be established:
wherein | L | purple*Representing the kernel norm, is the sum of the L singular values, and | | S | | luminance1Is represented by1And (4) norm. Tuning parameter λ is used to balance the nuclear norm terms and l1A norm term.
By way of example and not limitation, in the present system, the number of sample acquisitions M-637, xn(t)、ln(t)、snBoth (t) can be represented as 637 × 1 vectors and X, L, S as 637 × 43 dimensional matrices. Tuning parameters for a matrix of M N dimensions, as derived by mathematical analysis
Is the optimal choice. The above optimization problem can be expressed as
Therefore, in the present invention, λ is 0.0396.
And step S04, constructing an image of the target to be detected according to the echo signal of the target to be detected.
That is, the preprocessed radar echo data X and tuning parameter λ are input, and the above problem is solved by means of a convex optimization toolbox, so that a matrix S can be extracted, and target detection behind a wall is obtained. Fig. 5 is a cross-sectional view of a system scene, and fig. 6 is a result of the image after the solution, which can obtain the image reconstruction of the object at the position with 0.4m distance and 0.5m azimuth.
In summary, in the through-wall radar imaging method in the above embodiments of the present invention, the through-wall radar echo signal set is preprocessed, the clutter signals of the static background of the fixed wall are removed first, and then the clutter suppression problem of the foreign objects existing in the wall and the behind-wall target signal enhancement problem are modeled as a low-rank sparse representation problem by using the related low-rank characteristics of the foreign objects such as the steel bars or the pipelines in the wall and the spatial sparse characteristics of the target to be detected, so that the strong reflection of the foreign objects such as the pipelines or the steel bars in the wall is effectively removed, the through-wall radar image of the behind-wall target is enhanced, and the through-wall radar imaging quality is improved.
Example two
Referring to fig. 7, a through-wall radar imaging method according to a second embodiment of the present invention is shown, and the method specifically includes steps S11 through S17.
And step S11, controlling the transceiving antenna to uniformly step forward from left to right along the direction parallel to the wall body so as to enable the transceiving antenna to respectively collect through-wall radar echo signals at a plurality of observation position points.
And step S12, acquiring a through-wall radar echo signal set acquired by the transceiving co-located antenna at a plurality of observation position points.
Step S13, preprocessing the through-wall radar echo signal set by a two-dimensional high-pass filter to remove an echo signal of a fixed wall static background in the through-wall radar echo signal set, where the echo signal of the fixed wall static background includes an echo signal of an outer wall surface and an echo signal of an inner wall surface.
And step S14, decomposing the preprocessed through-wall radar echo signal set into a low-rank part and a sparse part according to the idea of low-rank sparse decomposition, wherein the low-rank part is an echo signal of foreign matters in a wall body, and the sparse part is an echo signal of a target to be detected.
And step S15, constructing a low-rank matrix L and a sparse matrix S respectively based on the low-rank part and the sparse part.
And S16, inputting the low-rank matrix L, the sparse matrix S and the preset tuning parameter lambda into a low-rank sparse optimization algorithm, and solving by means of a convex optimization tool box to extract echo signals of the target to be detected from the preprocessed through-wall radar echo signal set.
Wherein, the expression of the low-rank sparse optimization algorithm is as follows:
in the formula, | L |*Representing low rank momentsThe kernel norm of the matrix L is the sum of the singular values of the low rank matrix L, and | S |1L representing the sparse matrix S1Norm, λ is a preset tuning parameter for balancing the kernel norm term and l1A norm term.
That is, in the specific implementation, in the process of solving the optimization problem, the preprocessed through-wall radar echo signal set is automatically decomposed into a low-rank part and a sparse part based on the idea of low-rank sparse decomposition, and since echo signals generated by foreign matters such as reinforcing steel bars or pipelines in a wall body are regarded as related background signals, the signals of the part are low in rank and regarded as low-rank parts, and the echo signals of a target to be detected have spatial sparsity, the signals of the part are regarded as sparse parts; then, a low-rank matrix L and a sparse matrix S are respectively constructed based on the low-rank part and the sparse part, then, optimization solution needs to be carried out by means of a low-rank sparse optimization algorithm, the purpose of the optimization solution is to restrain the low-rank matrix L and reinforce the sparse matrix S, therefore, after the optimization solution, the reinforced sparse matrix S which is slightly interfered by the low-rank matrix L can be extracted, and echo signals of the target to be detected are extracted with high quality.
And step S17, constructing an image of the target to be detected according to the echo signal of the target to be detected.
EXAMPLE III
Another aspect of the present invention further provides a through-wall radar imaging apparatus, referring to fig. 8, which shows a through-wall radar imaging apparatus according to a third embodiment of the present invention, where the through-wall radar imaging apparatus includes:
the signal acquisition module 11 is configured to acquire a through-wall radar echo signal set acquired by the transceiving co-located antenna at a plurality of observation location points;
a signal preprocessing module 12, configured to preprocess the through-wall radar echo signal set to remove an echo signal of a fixed wall static background in the through-wall radar echo signal set, where the echo signal of the fixed wall static background includes an echo signal of an outer wall surface and an echo signal of an inner wall surface;
the signal post-processing module 13 is configured to input the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving, so as to extract an echo signal of a target to be detected from the preprocessed through-wall radar echo signal set;
and the image reconstruction module 14 is configured to construct an image of the target to be detected according to the echo signal of the target to be detected.
Further, in some optional embodiments of the present invention, the signal preprocessing module 12 is further configured to preprocess the through-wall radar echo signal set by using a two-dimensional high-pass filter, so as to remove an echo signal of a fixed wall static background in the through-wall radar echo signal set.
Further, in some optional embodiments of the present invention, the signal post-processing module 13 is further configured to decompose the preprocessed through-wall radar echo signal set into a low-rank portion and a sparse portion according to a low-rank sparse decomposition idea, where the low-rank portion is an echo signal of a foreign object in a wall body, and the sparse portion is an echo signal of a target to be detected; respectively constructing a low-rank matrix L and a sparse matrix S based on the low-rank part and the sparse part; and inputting the low-rank matrix L, the sparse matrix S and the preset tuning parameter lambda into a low-rank sparse optimization algorithm for solving.
Further, in some optional embodiments of the present invention, the expression of the low rank sparse optimization algorithm is:
in the formula, | L |*Representing the kernel norm of the low-rank matrix L, is the sum of the singular values of the low-rank matrix L, and | S | |)1L representing the sparse matrix S1Norm, λ is a preset tuning parameter for balancing the kernel norm term and l1A norm term.
Further, in some optional embodiments of the present invention, the signal post-processing module 13 is further configured to input the preprocessed through-wall radar echo signal set and the preset tuning parameter into the low-rank sparse optimization algorithm, and perform solution by using a convex optimization tool box.
Further, in some optional embodiments of the present invention, the through-wall radar imaging apparatus further includes:
and the antenna control module is used for controlling the transceiving antenna to uniformly step forward from left to right along the direction parallel to the wall body so as to enable the transceiving antenna to respectively collect through-wall radar echo signals at the plurality of observation position points.
The functions or operation steps of the modules and units when executed are substantially the same as those of the method embodiments, and are not described herein again.
In summary, in the through-wall radar imaging device in the above embodiments of the present invention, the echo signal set of the through-wall radar is preprocessed, the clutter signals of the static background of the fixed wall are removed first, and then the clutter suppression problem of the foreign objects existing in the wall and the behind-wall target signal enhancement problem are modeled as a low-rank sparse representation problem by using the related low-rank characteristics of the foreign objects such as the steel bars or the pipelines in the wall and the spatial sparse characteristics of the target to be detected, so that the strong reflection of the foreign objects such as the pipelines or the steel bars in the wall is effectively removed, the through-wall radar image of the behind-wall target is enhanced, and the imaging quality of the through-wall radar is improved.
Example four
Referring to fig. 9, a through-wall radar imaging apparatus according to a fourth embodiment of the present invention is shown, which includes a memory 20, a processor 10, and a computer program 30 stored in the memory and executable on the processor, where the processor 10 executes the computer program 30 to implement the through-wall radar imaging method as described above.
The processor 10 may be a Central Processing Unit (CPU), a controller, a microcontroller, a microprocessor or other data Processing chip in some embodiments, and is used to execute program codes stored in the memory 20 or process data, such as executing an access restriction program.
The memory 20 includes at least one type of readable storage medium, which includes a flash memory, a hard disk, a multimedia card, a card type memory (e.g., SD or DX memory, etc.), a magnetic memory, a magnetic disk, an optical disk, and the like. The memory 20 may 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 may also be an external storage device of the through-wall radar imaging apparatus in other embodiments, such as a plug-in hard disk provided on the through-wall radar imaging apparatus, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like. Further, the memory 20 may also include both an internal storage unit and an external storage device of the through-wall radar imaging apparatus. The memory 20 may be used not only to store application software installed in the through-wall radar imaging apparatus and various types of data, but also to temporarily store data that has been output or is to be output.
It should be noted that the configuration shown in fig. 9 does not constitute a limitation of the through-wall radar imaging device, and in other embodiments, the through-wall radar imaging device may include fewer or more components than those shown, or some components may be combined, or a different arrangement of components.
In summary, in the through-wall radar imaging device in the above embodiments of the present invention, the clutter signals of the static background of the fixed wall are removed first by preprocessing the echo signal set of the through-wall radar, and then the clutter suppression problem of the foreign objects existing in the wall and the behind-wall target signal enhancement problem are modeled as a low-rank sparse representation problem by using the related low-rank characteristics of the foreign objects such as the steel bars or the pipelines in the wall and the spatial sparse characteristics of the target to be detected, so that the strong reflection of the foreign objects such as the pipelines or the steel bars in the wall is effectively removed, the through-wall radar image of the behind-wall target is enhanced, and the imaging quality of the through-wall radar is improved.
EXAMPLE five
A fifth embodiment of the present invention provides a through-wall radar imaging system, including:
the through-wall radar imaging device of the fourth embodiment; and
and the transmitting and receiving co-located antenna is connected with the through-wall radar imaging equipment and can uniformly step forward from left to right along the direction parallel to the wall body.
An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the through-wall radar imaging method as described above.
Those of skill in the art will understand that the logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be viewed as implementing logical functions, can be embodied in any computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable storage medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable storage medium may even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A through-wall radar imaging method, the method comprising:
acquiring a through-wall radar echo signal set acquired by a transmitting-receiving co-located antenna at a plurality of observation position points;
preprocessing the through-wall radar echo signal set to remove echo signals of a fixed wall static background in the through-wall radar echo signal set, wherein the echo signals of the fixed wall static background comprise echo signals of the surface of an outer wall and echo signals of the surface of an inner wall;
inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving so as to extract an echo signal of a target to be detected from the preprocessed through-wall radar echo signal set;
and constructing an image of the target to be detected according to the echo signal of the target to be detected.
2. The through-wall radar imaging method according to claim 1, wherein the step of preprocessing the through-wall radar echo signal set to remove echo signals of a stationary wall static background in the through-wall radar echo signal set comprises:
and preprocessing the through-wall radar echo signal set through a two-dimensional high-pass filter so as to remove echo signals of a static background of a fixed wall body in the through-wall radar echo signal set.
3. The through-the-wall radar imaging method according to claim 1, wherein the step of inputting the preprocessed through-the-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving comprises:
decomposing the preprocessed through-wall radar echo signal set into a low-rank part and a sparse part according to the idea of low-rank sparse decomposition, wherein the low-rank part is an echo signal of foreign matters in a wall body, and the sparse part is an echo signal of a target to be detected;
respectively constructing a low-rank matrix L and a sparse matrix S based on the low-rank part and the sparse part;
and inputting the low-rank matrix L, the sparse matrix S and the preset tuning parameter lambda into a low-rank sparse optimization algorithm for solving.
4. The through-the-wall radar imaging method according to claim 3, wherein the expression of the low-rank sparse optimization algorithm is as follows:
in the formula, | L |*Representing the kernel norm of the low-rank matrix L, is the sum of the singular values of the low-rank matrix L, and | S | |)1L representing the sparse matrix S1Norm, λ is a preset tuning parameter for balancing the kernel norm term and l1A norm term.
5. The through-the-wall radar imaging method according to claim 1, wherein the step of inputting the preprocessed through-the-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving comprises:
and inputting the preprocessed through-wall radar echo signal set and the preset tuning parameters into the low-rank sparse optimization algorithm, and solving by means of a convex optimization tool box.
6. The through-the-wall radar imaging method according to any one of claims 1 to 5, wherein before the step of obtaining through-the-wall radar echo signal sets collected by the co-located transmitting and receiving antenna at a plurality of observation location points, the method further comprises:
and controlling the receiving and transmitting co-located antenna to uniformly step forward from left to right along the direction parallel to the wall body so as to enable the receiving and transmitting co-located antenna to respectively collect through-wall radar echo signals at the plurality of observation position points.
7. A through-wall radar imaging apparatus, the apparatus comprising:
the signal acquisition module is used for acquiring a through-wall radar echo signal set acquired by the transceiving co-located antenna at a plurality of observation position points;
the signal preprocessing module is used for preprocessing the through-wall radar echo signal set to remove echo signals of a fixed wall static background in the through-wall radar echo signal set, wherein the echo signals of the fixed wall static background comprise echo signals of the surface of an outer wall and echo signals of the surface of an inner wall;
the signal post-processing module is used for inputting the preprocessed through-wall radar echo signal set and preset tuning parameters into a preset low-rank sparse optimization algorithm for solving so as to extract an echo signal of a target to be detected from the preprocessed through-wall radar echo signal set;
and the image reconstruction module is used for constructing an image of the target to be detected according to the echo signal of the target to be detected.
8. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the through-wall radar imaging method according to any one of claims 1 to 6.
9. A through-wall radar imaging device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the through-wall radar imaging method as claimed in any one of claims 1 to 6 when executing the program.
10. A through-wall radar imaging system, the system comprising:
the through-the-wall radar imaging device of claim 9; and
and the transmitting and receiving co-located antenna is connected with the through-wall radar imaging equipment and can uniformly step forward from left to right along the direction parallel to the wall body.
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