CN116381665B - Method and system for positioning trapped person based on four-dimensional biological radar - Google Patents
Method and system for positioning trapped person based on four-dimensional biological radar Download PDFInfo
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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
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
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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
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/46—Indirect determination of position data
- G01S13/48—Indirect determination of position data using multiple beams at emission or reception
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
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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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
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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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- 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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- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Abstract
The invention discloses a method and a system for positioning trapped people based on four-dimensional biological radar. The method comprises the following steps: s1, rearranging echo data acquired by a four-dimensional biological radar to form a three-dimensional complex matrix; s2, obtaining a three-dimensional complex radar image after filtering, and splicing the three-dimensional complex radar image obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence; s3, calculating the energy entropy ratio of the four-dimensional radar image sequence; s4, weighting energy entropy ratio of the four-dimensional radar image sequence along a time dimension; s5, detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence, and clustering, wherein a clustering center is used as the three-dimensional position coordinates of each human body target; s6, respectively extracting vital sign signals corresponding to each human body from voxels at the three-dimensional position coordinates along the time dimension. The invention greatly improves the signal-to-noise ratio after processing, improves the signal-to-noise ratio of the buried human body detection by more than 30dB, and can realize human body detection and three-dimensional positioning of the buried human body with the depth of tens of meters.
Description
Technical Field
The invention relates to the technical field of biological radar signal processing, in particular to a method and a system for positioning trapped personnel based on four-dimensional biological radar.
Background
In the past 20 years, the number of the global earthquake disasters accounts for 8% of the total number of all disasters, and the death number exceeds 10 ten thousand, accounting for more than half of the death number of the disasters. Wherein 90% -95% of the casualties are caused by building damage and collapse. The effective rescue time after an earthquake or building collapse is called golden 72 hours and searching for and rescuing trapped persons in a short time helps minimize casualties.
The use of radar sensors to search and locate living persons behind ruins or walls is an important and urgent technique that can be used for searching and rescue tasks after avalanches, building collapses, earthquakes or other disasters occur. The transmitting antenna of the radar transmits electromagnetic waves to penetrate through barriers such as walls and ruins and then reaches a human body, then scatters back to the receiving antenna of the radar, and micro-motion signals such as respiration and heartbeat of the human body are extracted from radar echoes so as to detect and position the human body, thereby helping rescue workers to make detailed rescue plans and reducing secondary injury.
In penetration detection applications, vital sign signals are submerged in noise due to attenuation of signals by ruins, walls and the like, and micro-motions of trapped people after disaster are weak, so that detection difficulty is further increased. The penetration detection capability of the biological radar is affected by the multiple reflections and attenuations of the reinforced concrete slab or the structural layer. How to detect weak signals from noise is a key difficulty in post-disaster searching and rescuing by using a biological radar. Also, disaster survivors trapped in rubble or under snow need to be rescued in a short time, so the probe positioning method must guarantee accuracy and speed.
At present, a single channel or a smaller number of channels are generally adopted in a life detection radar in the market, and although the existence of a life body and a vital sign signal can be detected, the position of trapped people cannot be effectively positioned, and particularly in a scene where a plurality of trapped people exist, the detection and positioning of a plurality of targets in a three-dimensional space are very difficult.
The four-dimensional biological radar can realize three-dimensional space beam forming and imaging by adopting a multichannel array technology and an ultra-wideband signal processing technology, and distance direction, azimuth direction and height direction information of a living body are obtained, so that accurate three-dimensional positioning and detection can be carried out on a plurality of human targets. In addition, the four-dimensional biological radar can penetrate through barriers such as ruins and the like to extract vital sign information such as respiration, heartbeat and the like of a plurality of trapped people, is a key technology for processing biological radar signals, and is a research hotspot in the field of domestic and foreign biological radars.
Disclosure of Invention
The invention aims to provide a method and a system for positioning trapped people based on four-dimensional biological radar, which are used for overcoming the defects in the prior art.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for locating trapped people based on four-dimensional biological radar, comprising the following steps:
s1, rearranging echo data acquired by the four-dimensional biological radar to form a three-dimensional complex matrixWherein (1)>Is complex domain, G is the number of four-dimensional biological radar channels, K is the number of frequency points in the signal spectrum, and Q is the number of echo frames;
s2, performing coherent imaging on the region of interest by using a three-dimensional complex matrix, and performing three-dimensional spatial filtering by using a three-dimensional coherent factor to obtain a filtered three-dimensional complex radar imageSplicing the three-dimensional complex radar images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence +.>Where mxnxl is the number of voxels of the region of interest divided in three-dimensional space, t=q/F ps ，q＝0，1，…，Q-1，F ps R is a three-dimensional space coordinate vector for the corresponding frame rate;
s3, calculating a four-dimensional radar image sequence I t An energy-to-entropy ratio of (r, t);
s4, for four-dimensional radar image sequence I t (r, t) weighting the energy-entropy ratio along the time dimension;
s5, detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence, and clustering, wherein a clustering center is used as the three-dimensional position coordinates of each human body target;
s6, respectively extracting vital sign signals corresponding to each human body from voxels at the three-dimensional position coordinates along the time dimension;
s7, selecting the echo data obtained in the step S1 by adopting a sliding time window, and repeating the steps S2-S6 to obtain vital sign signals of a plurality of vital targets.
Further, the four-dimensional radar image sequence I in step S3 t The calculation formula of the energy entropy ratio of (r, t) is as follows:
wherein X (r, t, ω) i ) Is I t Time-frequency power spectrum, ω, of (r, t) i Is the frequency point corresponding to the time-frequency power spectrum.
Further, in the step S4, the calculation formula of the energy entropy ratio weighting is as follows:
I EER (r，t)＝I(r，t)E h (r，t)。
further, the expression of the vital sign signal in the step S6 is:
in the middle ofPhase (·) represents the Phase calculation function, f k Is the frequency spectrum.
The invention also provides a system for the method for positioning trapped people based on the four-dimensional biological radar, which comprises the following steps:
the arrangement module is used for rearranging echo data acquired by the four-dimensional biological radar to form a three-dimensional complex matrixWherein (1)>Is complex domain, G is the number of four-dimensional biological radar channels, K is the number of frequency points in the signal spectrum, and Q is the number of echo frames;
the splicing module performs coherent imaging on the region of interest by utilizing a three-dimensional complex matrix and performs three-dimensional spatial filtering by utilizing a three-dimensional coherent factor to obtain a filtered three-dimensional complex radar imageSplicing the three-dimensional complex radar images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence +.>Where mxnxl is the number of voxels of the region of interest divided in three-dimensional space, t=q/F ps ，q＝0，1，…，Q-1，F ps R is a three-dimensional space coordinate vector for the corresponding frame rate;
the computing module is used for computing a four-dimensional radar image sequence I t An energy-to-entropy ratio of (r, t);
weighting module for four-dimensional radar image sequence I t (r, t) weighting the energy-entropy ratio along the time dimension;
the detection module is used for detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence and clustering, and the clustering center is used as the three-dimensional position coordinates of each human body target;
the extraction module is used for respectively extracting vital sign signals corresponding to each human body along the time dimension for voxels at the three-dimensional position coordinates;
and the repeating module is used for selecting echo data acquired by the four-dimensional biological radar by adopting the sliding time window, and sequentially executing the splicing module, the calculating module, the weighting module, the detecting module and the extracting module to obtain vital sign signals of a plurality of vital targets.
Compared with the prior art, the invention has the advantages that: according to the invention, the four-dimensional image sequence is obtained by carrying out three-dimensional imaging on echo data received by the four-dimensional biological radar, filtering is carried out in an airspace by adopting a coherence factor, then the spatial-temporal joint processing is carried out by utilizing an energy-entropy ratio, so that the human body target is detected, the three-dimensional positioning of a plurality of trapped people is realized, vital signs such as respiration, heartbeat and the like of each trapped person can be further extracted, and the accurate three-dimensional positioning of trapped people in ruins and collapsed buildings after disaster and the vital sign measurement of the plurality of trapped people are realized. Compared with the prior art, the four-dimensional biological radar can realize detection and positioning of a plurality of targets, and as the coherent processing greatly improves the detection performance of the system, the signal-to-noise ratio is greatly improved after the processing, the signal-to-noise ratio of the buried human body detection under typical parameters is improved by more than 30dB, and the human body detection and three-dimensional positioning of the buried human body with the depth of tens of meters can be realized.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method of locating trapped people based on four-dimensional bioradars of the present invention.
FIG. 2 is an original three-dimensional radar image corresponding to a frame in the first embodiment;
FIG. 3 is a three-dimensional radar image processed by the method of the present invention corresponding to a certain frame in the first embodiment;
FIG. 4 is a single human target detected after clustering in embodiment one;
FIG. 5 is a human target vital sign micro-motion signal extracted in the first embodiment;
FIG. 6 is an original three-dimensional radar image corresponding to a frame in the second embodiment;
FIG. 7 is a three-dimensional radar image processed by the method of the present invention corresponding to a frame in the second embodiment;
FIG. 8 shows two human targets detected after clustering in the second embodiment;
fig. 9 is a vital sign micro-motion signal of two human body targets extracted in the second embodiment.
FIG. 10 is a schematic diagram of a system for locating trapped personnel based on four-dimensional bioradars in accordance with the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making clear and defining the scope of the present invention.
Example 1
The embodiment discloses a method for positioning trapped personnel based on four-dimensional biological radar, wherein the trapped personnel are positioned at a position about 3 meters below simulated building ruins, the building ruins are composed of reinforced concrete, structural plates, broken stones and the like, and the radar is arranged on the surfaces of the ruins. The four-dimensional biological radar in the embodiment adopts a planar antenna array with a 10-transmission and 10-reception MIMO structure, the frequency of the transmitted electromagnetic wave is 1.785 GHz-2.785 GHz, and the frame rate is F ps =10 Hz, i.e. the sampling time interval per frame of image is 0.1 seconds. The process flow of the method of the present embodiment is shown in fig. 1.
Step S1, collecting echo data of 60 seconds by a four-dimensional biological radar, rearranging the echo data of 256 frequency points of 10 transmission channels and 10 reception channels for 600 frames in total to form a three-dimensional complex matrixWherein (1)>Is complex domain, g=100 is four-dimensional biological radar channel number, k=256 is the number of frequency points in signal spectrum, and the spectrum is f k =1.785+ (k-1) ·0.004ghz, k=1, …,256, q=600 is the echo frame number.
S2, carrying out three-dimensional imaging on echo data of each frame of four-dimensional biological radar by using a backward projection algorithm, setting an interested region to be a region with the width of 4 meters, the depth of 1-5 meters and the length of 4 meters under the radar, carrying out coherent imaging on the interested region by using a radar echo data matrix to obtain a three-dimensional radar image of the interested region, and simultaneously carrying out three-dimensional spatial filtering by using three-dimensional coherent factors in the imaging process to obtain a three-dimensional complex radar image after filteringThe number of voxels M x N x L of the region of interest divided in three-dimensional space corresponds to 50 x 50, corresponding to X, Y and Z-axis, respectively. Splicing the three-dimensional images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence>Wherein t=g/10, q=0, 1, …,599, f ps =10 is the corresponding frame rate, r is the three-dimensional space coordinate vector; a frame of three-dimensional radar image of the resulting four-dimensional radar image sequence is shown in fig. 2.
Step S3, calculating a four-dimensional radar image sequence I t The energy entropy ratio of (r, t) is calculated as:
wherein X (r, t, ω) i ) Is I t Time-frequency power spectrum, ω, of (r, t) i Is the frequency point corresponding to the time-frequency power spectrum. The time-frequency power spectrum is calculated by short-time Fourier transform, and the sliding window duration of the short-time Fourier transform is selected to be 20 seconds.
Step S4, for the four-dimensional radar image sequence I t (r, t) edgeThe time dimension performs energy entropy ratio weighting, namely:
I EER (r，t)＝I(r，t)E h (r，t)
an enhanced radar image sequence is obtained, wherein one frame of three-dimensional image is shown in fig. 3.
Step S5, detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence and clustering, and the result is shown in fig. 4. The clustering center is used as the three-dimensional position coordinates of the detected human targets, 1 human target is detected in the embodiment, and the three-dimensional coordinates of the positioning result are (0.51 m,3.38m and-0.56 m).
Step S6, a four-dimensional radar image sequence I is obtained t Extracting corresponding vital sign jog signals along the time dimension from voxels at the three-dimensional position coordinates detected in (r, t):
wherein f c The phase (·) represents a phase calculation function, which is commonly used as an inverse tangent method, a differential cross-correlation method, a singular value decomposition method, etc., and in this embodiment, the phase is calculated by using the differential cross-correlation method, so as to obtain a vital sign micro-motion signal, as shown in fig. 5.
And S7, selecting the echo data obtained in the step S1 by adopting a sliding time window, and repeating the steps S2-S6 to realize real-time and dynamic three-dimensional detection positioning and physiological signal measurement on a plurality of living body targets.
Example two
The embodiment provides a method for positioning a plurality of trapped persons, wherein in the embodiment, two trapped persons are positioned at about 3 meters behind a narrow closed space formed by a simulated collapse building, the collapse building is formed by brick walls, reinforced concrete, structural plates and the like, and a radar is arranged on the outer surface of the closed space. The four-dimensional biological radar in the embodiment adopts a planar antenna array with a 10-transmission and 10-reception MIMO structure, the frequency of the transmitted electromagnetic wave is 1.785 GHz-2.785 GHz, and the frame rate is F ps =10hz, i.e. sampling of each frame of imageThe time interval is 0.1 seconds.
Step S1, collecting echo data of 60 seconds by a four-dimensional biological radar, rearranging the echo data of 256 frequency points of 10 transmission and 10 reception channels of which the total is 600 frames to form a three-dimensional complex matrixWherein (1)>Is complex domain, g=100 is four-dimensional biological radar channel number, k=256 is the number of frequency points in signal spectrum, and the spectrum is f k =1.785+ (k-1) ·0.004ghz, k=1, …,256, q=600 is the echo frame number.
S2, carrying out three-dimensional imaging on echo data of each frame of four-dimensional biological radar by using a backward projection algorithm, setting an interested region to be a region with the width of 4 meters, the depth of 1-5 meters and the length of 4 meters under the radar, carrying out coherent imaging on the interested region by using a radar echo data matrix to obtain a three-dimensional radar image of the interested region, and simultaneously carrying out three-dimensional spatial filtering by using three-dimensional coherent factors in the imaging process to obtain a three-dimensional complex radar image after filteringThe region of interest being divided in three dimensions voxel number m×n×l corresponding to 50 x 50. Splicing the three-dimensional images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence>Where t=q/10, g=0, 1, …,599, f ps =10 is the corresponding frame rate, r is the three-dimensional space coordinate vector; a frame of three-dimensional radar image of the resulting four-dimensional radar image sequence is shown in fig. 6.
Step S3, calculating a four-dimensional radar image sequence I t The energy entropy ratio of (r, t) is calculated as
Wherein X (r, t, f) is I t Time-frequency power spectrum of (r, t), f i Is the frequency point corresponding to the time-frequency power spectrum. The time-frequency power spectrum is calculated by short-time Fourier transform, and the sliding window duration of the short-time Fourier transform is selected to be 20 seconds.
Step S4, for the four-dimensional radar image sequence I t (r, t) weighting energy-entropy ratios along the time dimension, i.e
I EER (r，t)＝I(r，t)E h (r，t)
An enhanced radar image sequence is obtained, wherein one frame of three-dimensional image is shown in fig. 7.
Step S5, detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence and clustering, and the result is shown in fig. 8. The clustering center was used as the three-dimensional position coordinates of the detected human targets, 2 human targets were detected in this example, and the three-dimensional coordinates of the positioning results were (-0.46 m,3.22m, -0.89 m) and (0.91 m,2.92m, -0.15 m), respectively.
Step S6, a four-dimensional radar image sequence I is obtained t Respectively extracting corresponding vital sign inching signals from voxels at three-dimensional position coordinates corresponding to the two detected human targets in (r, t) along the time dimension
Wherein f c The = 2.285GHz, the angle represents an angle phase calculation function, and common phase calculation functions include an inverse tangent method, a differential cross-phase method, a singular value decomposition method, and the like, and in this embodiment, the phase is calculated by using the differential cross-phase method, so as to obtain vital sign micro-motion signals of two human targets, as shown in fig. 9.
And S7, selecting the echo data obtained in the step S1 by adopting a sliding time window, and repeating the steps S2 to S6 to realize real-time dynamic three-dimensional detection positioning and physiological signal measurement on a plurality of living body targets.
Example III
Referring to fig. 10, the present embodiment provides a system for implementing the methods of the first and second embodiments, including: the arrangement module 1 is used for rearranging echo data acquired by the four-dimensional biological radar to form a three-dimensional complex matrixWherein (1)>Is complex domain, G is the number of four-dimensional biological radar channels, K is the number of frequency points in the signal spectrum, and Q is the number of echo frames; the splicing module 2 performs coherent imaging on the region of interest by utilizing a three-dimensional complex matrix and performs three-dimensional spatial filtering by utilizing a three-dimensional coherent factor to obtain a filtered three-dimensional complex radar image +.>Splicing the three-dimensional complex radar images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence +.>Where mxnxl is the number of voxels of the region of interest divided in three-dimensional space, t=q/F ps ，q＝0，1，…，Q-1，F ps R is a three-dimensional space coordinate vector for the corresponding frame rate; a calculation module 3 for calculating a four-dimensional radar image sequence I t An energy-to-entropy ratio of (r, t); weighting module 4 for a four-dimensional radar image sequence I t (r, t) weighting the energy-entropy ratio along the time dimension; the detection module 5 is used for detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence and clustering, and the clustering center is used as the three-dimensional position coordinates of each human body target; the extraction module 6 is used for respectively extracting vital sign signals corresponding to each human body along the time dimension for voxels at the three-dimensional position coordinates; the repeating module 7 is configured to select echo data acquired by the four-dimensional biological radar by using a sliding time window, and sequentially execute the stitching module 2, the calculating module 3, the weighting module 4, the detecting module 5, and the extracting module 6 to obtain a plurality of living body targetsIs a vital sign signal of (a).
According to the invention, the four-dimensional image sequence is obtained by carrying out three-dimensional imaging on echo data received by the four-dimensional biological radar, filtering is carried out in an airspace by adopting a coherence factor, then the spatial-temporal joint processing is carried out by utilizing an energy-entropy ratio, so that the human body target is detected, the three-dimensional positioning of a plurality of trapped people is realized, vital signs such as respiration, heartbeat and the like of each trapped person can be further extracted, and the accurate three-dimensional positioning of trapped people in ruins and collapsed buildings after disaster and the vital sign measurement of the plurality of trapped people are realized. Compared with the prior art, the four-dimensional biological radar can realize detection and positioning of a plurality of targets, and as the coherent processing greatly improves the detection performance of the system, the signal-to-noise ratio is greatly improved after the processing, the signal-to-noise ratio of the buried human body detection under typical parameters is improved by more than 30dB, and the human body detection and three-dimensional positioning of the buried human body with the depth of tens of meters can be realized.
The invention has high three-dimensional positioning precision, and high resolution penetration imaging realizes accurate three-dimensional positioning of trapped personnel; the multi-target detection capability of the invention is strong, the detection of a plurality of human targets is realized by three-dimensional space perception, and the multi-target detection capability of the biological radar is expanded; the invention has strong noise suppression capability, and the signal-to-noise ratio is greatly improved under the complex environment of the obstacle by combining space-time treatment, thereby greatly suppressing the interference of noise waves such as ruins, walls and the like on weak physiological micro-motion signals.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, the patentees may make various modifications or alterations within the scope of the appended claims, and are intended to be within the scope of the invention as described in the claims.
Claims (2)
1. A method for locating trapped people based on four-dimensional biological radar, comprising the steps of:
s1, rearranging echo data acquired by the four-dimensional biological radar to form a three-dimensional complex matrixWherein,is complex domain, G is the number of four-dimensional biological radar channels, K is the number of frequency points in the signal spectrum, and Q is the number of echo frames;
s2, performing coherent imaging on the region of interest by using a three-dimensional complex matrix, and performing three-dimensional spatial filtering by using a three-dimensional coherent factor to obtain a filtered three-dimensional complex radar imageSplicing the three-dimensional complex radar images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence +.>Where mxnxl is the number of voxels of the region of interest divided in three-dimensional space, t=q/F ps ，g＝0，1，…，Q-1，F ps R is a three-dimensional space coordinate vector for the corresponding frame rate;
s3, calculating a four-dimensional radar image sequence I t An energy-to-entropy ratio of (r, t);
s4, for four-dimensional radar image sequence I t (r, t) weighting the energy-entropy ratio along the time dimension;
s5, detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence, and clustering, wherein a clustering center is used as the three-dimensional position coordinates of each human body target;
s6, respectively extracting vital sign signals corresponding to each human body from voxels at the three-dimensional position coordinates along the time dimension;
s7, selecting the echo data obtained in the step S1 by adopting a sliding time window, and repeating the steps S2-S6 to obtain vital sign signals of a plurality of vital targets;
the four-dimensional radar image sequence I in the step S3 t The calculation formula of the energy entropy ratio of (r, t) is as follows:
wherein X (r, t, w) i ) Is I t Time-frequency power spectrum, ω, of (r, t) i Frequency points corresponding to the time-frequency power spectrum;
the calculation formula of the energy entropy ratio weighting in the step S4 is as follows:
I EER (r，t)＝I(r，t)E h (r，t)；
the expression of the vital sign signal in the step S6 is:
wherein f c Is the center frequency of the radar transmit signal.
2. A system of the four-dimensional bioradar-based method of locating trapped people of claim 1, comprising:
the arrangement module is used for rearranging echo data acquired by the four-dimensional biological radar to form a three-dimensional complex matrixWherein (1)>Is complex domain, G is the number of four-dimensional biological radar channels, K is the number of frequency points in the signal spectrum, and Q is the number of echo frames;
the splicing module performs coherent imaging on the region of interest by utilizing a three-dimensional complex matrix and performs three-dimensional spatial filtering by utilizing a three-dimensional coherent factor to obtain a filtered three-dimensional complex radar imageSplicing the three-dimensional complex radar images obtained by continuous measurement into a four-dimensional radar image sequence according to time sequence +.>Where mxnxl is the number of voxels of the region of interest divided in three-dimensional space, t=q/F ps ，g＝0，1，…，Q-1，F ps R is a three-dimensional space coordinate vector for the corresponding frame rate;
the computing module is used for computing a four-dimensional radar image sequence I t An energy-to-entropy ratio of (r, t);
weighting module for four-dimensional radar image sequence I t (r, t) weighting the energy-entropy ratio along the time dimension;
the detection module is used for detecting a plurality of targets in each frame of three-dimensional image of the four-dimensional radar image sequence and clustering, and the clustering center is used as the three-dimensional position coordinates of each human body target;
the extraction module is used for respectively extracting vital sign signals corresponding to each human body along the time dimension for voxels at the three-dimensional position coordinates;
and the repeating module is used for selecting echo data acquired by the four-dimensional biological radar by adopting the sliding time window, and sequentially executing the splicing module, the calculating module, the weighting module, the detecting module and the extracting module to obtain vital sign signals of a plurality of vital targets.
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