CN110680349A - Pulse lie detection method and device based on linear frequency modulation - Google Patents

Pulse lie detection method and device based on linear frequency modulation Download PDF

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CN110680349A
CN110680349A CN201911036322.0A CN201911036322A CN110680349A CN 110680349 A CN110680349 A CN 110680349A CN 201911036322 A CN201911036322 A CN 201911036322A CN 110680349 A CN110680349 A CN 110680349A
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马碧云
元达鹏
刘娇蛟
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South China University of Technology SCUT
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Abstract

The invention discloses a pulse lie detection method and device based on linear frequency modulation. Combining with pre-distortion processing, pulse compression and layered inversion echo algorithm, and obtaining the position (depth) of each reflecting surface through the time delay between each reflecting echo; inverting the amplitude of the transmitting signal and the amplitude of the echo signal in each reflecting layer by using an attenuation function of ultrasonic waves in a body in an iterative mode, and calculating the reflection coefficient of each reflecting surface; the reflection coefficient can determine the tissue composition of each reflection layer, and obtain multi-dimensional pulse information such as depth, frequency, amplitude and the like of the pulse, so that more dimensional references can be provided for judging lie detection results.

Description

Pulse lie detection method and device based on linear frequency modulation
Technical Field
The invention relates to the technical fields of acoustic detection, signal processing and the like, in particular to a pulse lie detection method and device based on linear frequency modulation.
Background
The lie detection technology is a criminal psychological test technology, in the early stage of detection work, detection personnel find a suspected object according to the conditions of preliminary detection and investigation, but no definite evidence is provided to determine whether the object is a criminal, and a method of calling or transmitting is usually adopted to carry out positive examination so as to eliminate or confirm criminal suspicion. But both the perpetrator and the innocent person can be extremely debated from the crime, which provides a temporary difficult investigation or a considerable time and expense for the investigation. At this time, if the lie detection technology is used, a large number of innocent suspects can be rapidly eliminated, key suspects can be screened out, criminals can be directly identified under the condition of good conditions, then inquiries and surveys are carried out around the key suspects, the work can be doubled with half effort, and the case solving efficiency is greatly improved.
Modern science proves that the physiology of people actually changes when lying, and some people can observe a series of unnatural human body actions such as scratching ears, shaking legs and feet and the like by naked eyes. Still other physiological changes are not readily perceptible, such as: respiratory rate and blood volume abnormalities, the appearance of respiratory depression and breath-hold; the pulse is accelerated, the blood pressure is increased, the blood output is increased, and the components are changed, so that the skin on the face and the neck is obviously pale or reddish; increased secretion of the subcutaneous sweat glands leads to sweating of the skin, between the eyes or the upper lip first, and especially pronounced sweating of the fingers and palms; enlarging the pupil of the eye; gastric contraction, abnormal secretion of digestive juice, resulting in dry mouth, tongue, and lip; muscle tension, trembling, resulting in speech loss. These physiological parameters are governed by the autonomic nervous system, and are generally not controlled by human consciousness, but are autonomous in movement, and a series of conditioned reflex phenomena occur under external stimulation. All this escapes without the "eyes" of the lie detector. Lie detection generally measures a person's physiological changes from three aspects, namely pulse, respiration and skin resistance, with pulse being the first place; therefore, if multi-dimensional pulse information can be obtained, the accuracy of judging the lie detection result can be improved.
The current pulse detection device mainly adopts pressure and optical sensors to sense the pulse and is matched with different types of mechanical devices, such as: the pulse simulator comprises a micro motor, an electromagnetic valve, an air pump, a hydraulic pump device and the like, and is used for simulating hands to acquire pulse information. A number of patents disclose pulse detection devices based on pressure and temperature sensing devices, such as: chinese patent, grant no: ZL86107657.3, authorization number: CN102411615, application No.: 301310629076.6, etc. The heart of the method is to sense the pulse information of the patient through a pressure sensor fixed on the hand, and to calibrate the error of the pressure sensor by using a temperature sensor, however, the method still has some defects of a touch type sensor, such as: the precision is not high; the sensor and the wrist joint layer degree have great influence on the result, and a high-precision and high-cost air pump and a hydraulic device are needed to reduce errors.
Ultrasound has long been used to acquire pulse data because of its safety, non-destructive, etc., features, such as: chinese patent, application number: 200610083339.8, obtaining various parameters of the pulse by obtaining the three-dimensional graph of the pulse by a medical array ultrasonic three-dimensional imaging device; however, the method adopts the pulse signal as the detection signal, the pulse signal is generally used for imaging, the pulse signal is used in combination with the array probe, and the operation process is complex.
Disclosure of Invention
The invention aims to realize accurate acquisition of pulse information and provides a pulse lie detection method and device based on linear frequency modulation.
The first purpose of the invention can be achieved by the following technical scheme:
a pulse lie detection method based on linear frequency modulation comprises the following steps:
s1, signal preprocessing: a non-array probe is adopted to transmit a linear frequency modulation continuous signal, and the linear frequency modulation signal has the characteristics of accuracy, multipath resistance, artifact removal and the like; the bandwidth of the echo signal is not limited to the probe by weighting the impulse response of the probe through the amplitude, so that the axial resolution is improved; finally, using a Lanczos window function as an amplitude reduction function to reduce the side lobe after pulse pressure;
s2, pulse compression: performing pulse compression processing on the received reflection echo to obtain narrow pulse with higher peak power; and reducing the side lobe after pulse compression by adding a Hamming window;
s3, layered inversion: by analyzing the time delay information of each reflection echo after pulse compression, the reflection coefficient of each reflection layer is inverted, the organized reflection coefficient is compared, and the position information of the pulse (blood vessel) is positioned, so that the depth, the frequency, the amplitude and the organization state of the pulse are obtained, and more dimensional references are provided for lie detection.
Further, the signal preprocessing in step S1 specifically includes the following steps:
s1.1, determining a signal form: because the linear signal has good autocorrelation characteristic, the original signal is a linear frequency modulation signal and is obtained by the input of a user
Wherein f is0Is the center frequency of the signal, K is the signal bandwidth, T is the time width of the signal, a is the amplitude of the signal;
s1.2, amplitude weighting, namely preprocessing the linear frequency modulation by amplitude weighting:
xpre(t)＝Mprob(t)Mdecr(t)x(t),0≤t≤T
wherein M isprob(t) is a probe-based amplitude weighting function;
since the impulse response of the ultrasound probe can be approximated as a cosine wave of the gaussian envelope:
wherein, Δ fuIs the bandwidth of the probe, f0Is the center frequency of the probe, μ is a constant; the amplitude weighting function can therefore be expressed as the inverse of a gaussian function:
where D is a weighting coefficient, indicating the degree of amplitude weighting. The smaller the value of D, the greater the degree to which the signal amplitude is weighted; the value of D is related to the impulse response of the probe, the bandwidth and the time width of the signal;
and Mdecr(t) is the Lanczos window function, with the aim of reducing the pulse pressure side lobe amplitude:
Figure BDA0002251600970000034
wherein the content of the first and second substances,
Figure BDA0002251600970000041
m is the amplitude reduction length.
Further, the pulse compression in step S2 specifically includes the following steps:
s2.1, obtaining a matched filtering function: the criterion for maximizing the output signal-to-noise ratio can be given as an expression for the matched filter:
hmatch(t)＝kx*(t0-t)
wherein k is an arbitrary constant, x*Being the conjugate of the chirp signal, t0Is the expected offset;
s2.2, adding a Hamming window function on the basis of the matched filter to obtain an expression of the mismatch filter as follows:
hmismatch(t)＝w(t)hmatch(t)
wherein, the definition of the Hanmming window w (n) is as follows:
Figure BDA0002251600970000042
wherein β is 0.46, and N is the total length of the hamming window;
s2.3, pulse compression: after the reflected echo received by the receiving probe passes through the mismatch filter, the narrow pulse with higher peak power can be obtained:
y(t)＝conv(r(t),F-1(X*(f)Hmismatch(f)))
where r (t) is the reflected echo, F-1For inverse Fourier transform, X*(f) Is the conjugate of the linear frequency-modulated signal after Fourier transform, Hmismatch(f) As a systematic function of the mismatched filter, conv (×) is a convolution operation.
Further, the hierarchical inversion in step S3 specifically includes the following steps:
s3.1, calculating the relative distance of each reflecting layer: the time delay result n corresponding to each narrow pulse peak valueiAccording to the samplingFrequency and speed of sound converted into distance di：
Figure BDA0002251600970000043
Wherein f issIs the system sampling frequency, C is the average sound velocity of the ultrasonic wave in the human tissue; diNamely, the distance of each reflecting surface relative to the skin;
s3.2, attenuation function: the attenuation function of the ultrasonic signal in the human body is as follows:
Figure BDA0002251600970000051
wherein, U0Is the initial amplitude of the signal, f is the frequency of the signal, alphaNThe attenuation coefficient of the Nth layer of tissue in the body, and d is the moving distance of the signal in the body;
s3.3, amplitude X of original transmitting signal0After the transmission of the known initial reflecting layer and the attenuation function U of the human tissue, the amplitude X at the first reflecting layer is obtained1：
Figure BDA0002251600970000052
Wherein R is0Is the reflection coefficient of the known initial reflection layer, alpha1Attenuation coefficient, m, from the initial reflective layer to the first reflective layer1＝d1-d0The distance between the first reflecting layer and the initial reflecting layer;
s3.4, and the echo Y is reflected0Then the amplitude Y at the first reflecting layer is obtained through the attenuation of human tissues and the transmission of the known initial reflecting layer1：
Figure BDA0002251600970000053
S3.5, so the reflection coefficient of the first reflective layer is:
Figure BDA0002251600970000054
wherein, X1Original transmission signal X0Amplitude at the first reflective layer, Y1For reflecting an echo Y0An amplitude at the first reflective layer;
s3.6, and so on, obtaining the amplitude X of the emission signal at the i-th layer reflecting surface through iterationiWith the amplitude Y of the reflected echo signal at the i-th layer reflecting surfacei：
Figure BDA0002251600970000055
Wherein n is the total number of reflecting surfaces, mi＝di-di-1Is the distance between the ith layer and the (i-1) th layer, Ri-1Is the reflection coefficient of the i-1 st layer, alphaiThe attenuation coefficient from the i-1 st layer to the i-th layer is shown;
s3.7, and thus the reflection coefficient of the i-th layer reflective surface:
Figure BDA0002251600970000061
s3.8, after the reflection coefficients of all layers are obtained, the tissue composition of all the reflection layers can be determined by comparing the organized reflection coefficients, so that multi-dimensional information such as pulse depth, frequency, amplitude information and the like is obtained; thereby providing multi-dimensional pulse reference for judging lie detection results.
The other purpose of the invention can be achieved by the following technical scheme:
the utility model provides a pulse lie detection device based on linear frequency modulation adopts the mode of data processing end and the separation of data acquisition end, and the concrete principle is as follows:
the pulse lie detection device based on the linear frequency modulation is composed of a data acquisition end 101 and a data processing end 102, and the two parts are related through radio electromagnetic waves. The data acquisition terminal 101 is responsible for receiving and transmitting ultrasonic waves, converting analog signals and digital signals and wirelessly transmitting echo signals; the data processing end 102 is responsible for improving the axial resolution and reducing side lobes through preprocessing of the transmitted signals; meanwhile, the reflected echo signals are subjected to post-processing to obtain multi-dimensional information such as pulse depth, frequency, amplitude and the like, so that more comprehensive reference is provided for judging lie detection results.
The data acquisition end 101 of the pulse lie detection device based on the chirp is responsible for data acquisition, data forwarding and time sequence control of a system process. The ultrasonic probe comprises a transceiving logic unit 201, a wireless transmitting unit 202, a data storage unit 203, an AD/DA conversion unit 204, a power amplification unit 205, a non-array ultrasonic probe unit 206 and a low noise amplification unit 207. The connection relationship of the components is as follows:
the transceiving logic unit 201 is connected to the wireless transmitting unit 202, the data storage unit 203, and the AD/DA conversion unit 204, and is responsible for timing control of transceiving processes, such as interval control of transmitting signals, timing control of external devices (memory, AD/DA chip, wireless module), and the like; the wireless transmitting unit 202 is connected to the AD/DA converting unit 204, and is responsible for sending the digitally quantized ultrasonic reflection echo to the data processing terminal 102 in the form of a wireless electromagnetic wave for analysis and processing; the data storage unit 203 is connected with the AD/DA conversion unit 204 and the transceiving logic unit 201, and is responsible for storing the signal data preprocessed in the data processing terminal 102, and the transceiving logic unit 201 can read the data used therein through a certain flow logic; the AD/DA conversion unit 204 is connected with the power amplification unit 205, the low-noise amplification unit 207, the wireless transmission unit 202 and the data storage unit 203, and is responsible for mutually converting the analog signals converted by the ultrasonic probe and the digital signals which can be identified by the processing chip; the power amplification unit 205 is connected with the non-array ultrasonic probe unit 206 and is responsible for converting the low-voltage signal into a driving signal capable of driving the non-array ultrasonic probe unit 206; the low-noise amplification unit 207 is connected with the non-array ultrasonic probe unit 206 and is responsible for amplifying the electric signals converted by the non-array ultrasonic probe unit 206 through a low-noise amplifier; the non-array ultrasound probe unit 206 is responsible for converting between electrical signals and non-array ultrasound signals, i.e. converting between electrical energy and acoustic energy.
The data processing terminal 102 of the pulse lie detector based on chirp is responsible for analyzing and processing data, and includes a signal preprocessing unit 301, a wireless receiving unit 302, and a signal post-processing unit 303. The connection relationship of the components is as follows:
if the data storage unit 203 has no data to store or needs to update the transmitted signal, the signal preprocessing unit 301 is connected with the data storage unit 203 and is responsible for performing predistortion processing on the signal, so that the axial resolution is improved and side lobes are reduced; the wireless receiving unit 302 is connected with the signal post-processing unit 303 and is responsible for receiving ultrasonic echo data from a data acquisition end; the signal post-processing unit 303 is responsible for post-processing the data of the wireless receiving unit 302 to obtain multi-dimensional information such as pulse depth, frequency, amplitude, and the like, so as to provide a more comprehensive reference for determining the lie detection result.
Compared with the prior art, the invention has the following advantages and effects:
(1) the invention uses the continuous signal of linear frequency modulation as the transmitting signal, obtains various information of pulse by processing the reflected echo, and has the advantages of less probes (non-array probes), high precision and multipath resistance compared with pulse signals for imaging; compared with a pressure sensor, the contact force of the device to a detection point is not required to be considered;
(2) the invention combines pre-distortion treatment, pulse compression and layered inversion echo algorithm, can obtain a better balance in the contradiction of improving axial resolution and reducing side lobe, obtain the time delay information of each reflection echo, thus the reflection coefficient of each reflection layer is obtained, the tissue composition of each reflection layer can be determined by comparing the organized reflection coefficients, thus multi-dimensional information such as pulse depth, frequency, amplitude and the like is obtained, and more references are provided for judging lie detection results;
(3) the invention adopts a wireless data return mode, so that the worn data acquisition end only carries out simple data acquisition, and a complex algorithm is realized and placed at the data processing end, thereby reducing the volume of the data acquisition end and reducing the power consumption;
in conclusion, the invention can measure multidimensional information such as pulse depth, frequency, amplitude and the like, provides more references for judging lie detection results, and has the advantages of high precision, simple device, convenient use and the like; the invention quantifies the pulse information, and after real-time analysis and storage, the pulse information can be used as a sample of big data for cluster analysis, thereby laying a foundation for big data analysis of future lie detection technology.
Drawings
FIG. 1 is a block diagram of a chirp-based pulse lie detection device as disclosed in the present invention;
FIG. 2 is a block diagram of a data processing side disclosed in the present invention;
FIG. 3 is a block diagram of a data acquisition end according to the present disclosure;
FIG. 4 is an exemplary graph of a layered inversion echo disclosed herein.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples
The lie detection technology can rapidly eliminate a large number of innocent suspects through a series of changes generated by the person in physiology when the person lies, screen out key suspects, directly identify criminals under good conditions, and then carry out interrogation and investigation around the key suspects, thereby being capable of achieving double results with half effort and greatly improving the case solving efficiency.
The physiological change during lie is reflected in abnormal respiration rate and blood volume, and respiratory depression and breath holding occur; the rapid pulse, the increase of blood pressure, the increase of blood output and the change of components cause the obvious pale or reddish skin on the face and the neck, etc. Therefore, the multi-dimensional detection of the pulse can provide a more comprehensive reference for judging the lie detection result.
In view of this, the present embodiment provides a pulse lie detection method based on chirp. Based on the physical characteristics of ultrasonic waves, a non-array ultrasonic probe is adopted to transmit a linear frequency modulation continuous signal, and a pre-distortion processing, pulse compression and layered inversion echo algorithm is used on a signal processing method, wherein the method comprises the following steps: 1) the signal transmission counteracts the influence of the impulse response of the transmitting probe on the transmitting signal through a predistortion technology, so that the bandwidth of the echo signal is not limited to the probe, and the axial resolution is improved; increasing an amplitude reduction function to reduce side lobes; 2) the signal receiving adopts pulse compression to recover the axial resolution, thereby obtaining the time delay among all the reflection echoes; 3) the position (depth) of each reflecting surface can be obtained by time delay; the reflection coefficient of each layer of reflecting surface can be calculated iteratively by combining the attenuation function of the ultrasonic wave in the body; through the reflection coefficient, the tissue composition of each reflection layer can be determined, so that multi-dimensional information such as pulse depth, frequency, amplitude and the like can be obtained, and more dimensional references can be provided for judging lie detection results.
The embodiment discloses a pulse lie detection method based on linear frequency modulation, which comprises the following steps:
s1, signal preprocessing: a non-array probe is adopted to transmit a linear frequency modulation continuous signal, and the linear frequency modulation signal has the characteristics of accuracy, multipath resistance, artifact removal and the like; the bandwidth of the echo signal is not limited to the probe by weighting the impulse response of the probe through the amplitude, so that the axial resolution is improved; finally, using a Lanczos window function as an amplitude reduction function to reduce the side lobe after pulse pressure;
the signal preprocessing in step S1 specifically includes the following steps:
s1.1, determining a signal form: because the linear signal has good autocorrelation characteristics, the original signal is a chirp signal, and is obtained by the input of a user:
wherein f is0Is the center frequency of the signal, K is the signal bandwidth, T is the time width of the signal;
s1.2, amplitude weighting: in order to limit the bandwidth of the echo signal to the probe and reduce the side lobe after pulse pressure, amplitude weighting pretreatment needs to be carried out on the linear frequency modulation:
xpre(t)＝Mprob(t)Mdecr(t)x(t),tC[0,T]
wherein M isprob(t) is based on the amplitude weighting function of the probe to counteract the effect of the probe on the chirp signal; since the impulse response of the ultrasound probe can be approximated as a cosine wave of the gaussian envelope:
wherein, Δ fuIs the-6 dB bandwidth, f, of the probe0Is the center frequency of the probe, α is a constant 1.2ln 10; the amplitude weighting function can therefore be expressed as the inverse of a gaussian function:
Figure BDA0002251600970000102
where D is a weighting coefficient, indicating the degree of amplitude weighting. The smaller the value of D, the greater the degree to which the signal amplitude is weighted; the value of D is related to the impulse response of the probe, the bandwidth and the time width of the signal;
and Mdecr(t) is the Lanczos window function, with the aim of reducing the pulse pressure side lobe amplitude:
Figure BDA0002251600970000103
wherein the content of the first and second substances,
Figure BDA0002251600970000104
m is amplitude cutThe length is reduced.
S2, pulse compression: performing pulse compression processing on the received reflection echo to obtain narrow pulse with higher peak power; and reducing the side lobe after pulse compression by adding a Hamming window;
the pulse compression in step S2 specifically includes the following steps:
s2.1, obtaining a matched filtering function: the criterion for maximizing the output signal-to-noise ratio can be given as an expression for the matched filter:
hmatch(t)＝kx*(t0-t)
wherein k is an arbitrary constant, x*Being the conjugate of the chirp signal, t0Is the expected offset;
s2.2, adding a Hamming window function on the basis of the matched filter to obtain an expression of the mismatch filter as follows:
hmismatch(t)＝w(t)hmatch(t)
wherein, the definition of the Hanmming window w (n) is as follows:
Figure BDA0002251600970000111
wherein β is 0.46, and N is the total length of the hamming window;
s2.3, pulse compression: after the reflected echo received by the receiving probe passes through the mismatch filter, the narrow pulse with higher peak power can be obtained:
y(t)＝conv(r(t),F-1(X*(f)Hmismatch(f)))
where r (t) is the reflected echo, F-1For inverse Fourier transform, X*(f) Is the conjugate of the linear frequency-modulated signal after Fourier transform, Hmismatch(f) As a systematic function of the mismatched filter, conv (×) is a convolution operation.
S3, layered inversion: reflecting coefficients of all reflecting layers are inverted by analyzing time delay information of all reflected echoes after pulse compression, and the organized reflecting coefficients are compared to position information of pulse (blood vessel), so that the depth, frequency, amplitude and organization state of the pulse are obtained, and more dimensional references are provided for lie detection;
the hierarchical inversion in step S3 specifically includes the following steps:
s3.1, calculating the relative distance of each reflecting layer: the time delay result n corresponding to each narrow pulse peak valueiConverting into distance d according to sampling frequency and sound velocityi：
Figure BDA0002251600970000112
Wherein f issIs the system sampling frequency, C is the average sound velocity of the ultrasonic wave in the human tissue; diNamely, the distance of each reflecting surface relative to the skin;
s3.2, attenuation function: the attenuation function of the ultrasonic signal in the human body is as follows:
Figure BDA0002251600970000113
wherein, U0Is the initial amplitude of the signal, f is the frequency of the signal, alphaNThe attenuation coefficient of the Nth layer of tissue in the body, and d is the moving distance of the signal in the body;
s3.3, amplitude X of original transmitting signal0After the transmission of the known initial reflecting layer and the attenuation function U of the human tissue, the amplitude X at the first reflecting layer is obtained1：
Figure BDA0002251600970000121
Wherein R is0Is the reflection coefficient of the known initial reflection layer, alpha1Attenuation coefficient, m, from the initial reflective layer to the first reflective layer1＝d1-d0The distance between the first reflecting layer and the initial reflecting layer;
s3.4, and the echo Y is reflected0Then the amplitude Y at the first reflecting layer is obtained through the attenuation of human tissues and the transmission of the known initial reflecting layer1：
Figure BDA0002251600970000122
S3.5, so the reflection coefficient of the first reflective layer is:
Figure BDA0002251600970000123
wherein, X1Original transmission signal X0Amplitude at the first reflective layer, Y1For reflecting an echo Y0An amplitude at the first reflective layer;
s3.6, and so on, obtaining the amplitude X of the emission signal at the i-th layer reflecting surface through iterationiWith the amplitude Y of the reflected echo signal at the i-th layer reflecting surfacei：
Figure BDA0002251600970000125
Wherein n is the total number of reflecting surfaces, mi＝di-di-1Is the distance between the ith layer and the (i-1) th layer, Ri-1Is the reflection coefficient of the i-1 st layer, alphaiThe attenuation coefficient from the i-1 st layer to the i-th layer is shown;
s3.7, and thus the reflection coefficient of the i-th layer reflective surface:
Figure BDA0002251600970000126
s3.8, after the reflection coefficients of all layers are obtained, the tissue composition of all the reflection layers can be determined by comparing the organized reflection coefficients, so that multi-dimensional information such as pulse depth, frequency, amplitude information and the like is obtained; thereby providing multi-dimensional pulse reference for judging lie detection results.
Example two
The embodiment provides a pulse lie detection device based on linear frequency modulation, and the device organically combines technologies such as acoustic detection, power electronics and signal processing together, and has the characteristics of small volume and low cost. And according to the physical characteristics of ultrasonic waves, a non-array ultrasonic probe is adopted to transmit linear frequency modulation continuous signals, and the depth, the frequency, the amplitude and the tissue state of the pulse are finally obtained by combining pre-distortion processing, pulse compression and a layered inversion echo algorithm on a signal processing method. The apparatus is described in further detail below with reference to fig. 1-4.
The pulse lie detector based on chirp in this embodiment is shown in fig. 2, and is composed of a data acquisition end 101 and a data processing end 102, and the two parts are related to each other through radio electromagnetic waves. The data acquisition terminal 101 is responsible for receiving and transmitting ultrasonic waves, converting analog signals and digital signals and wirelessly transmitting echo signals; the data processing end 102 is responsible for improving the axial resolution and reducing side lobes through preprocessing of the transmitted signals; meanwhile, the reflected echo signals are subjected to post-processing to obtain multi-dimensional information such as pulse depth, frequency, amplitude and the like, so that more comprehensive reference is provided for judging lie detection results.
The data acquisition end 101 of the pulse lie detector based on chirp is shown in fig. 3, and is responsible for data acquisition, data forwarding, and time sequence control of a system process. The ultrasonic probe comprises a transceiving logic unit 201, a wireless transmitting unit 202, a data storage unit 203, an AD/DA conversion unit 204, a power amplification unit 205, a non-array ultrasonic probe unit 206 and a low noise amplification unit 207. The connection relationship of the components is as follows:
the transceiving logic unit 201 is connected to the wireless transmitting unit 202, the data storage unit 203, and the AD/DA conversion unit 204, and is responsible for timing control of transceiving processes, such as interval control of transmitting signals, timing control of external devices (memory, AD/DA chip, wireless module), and the like; the wireless transmitting unit 202 is connected to the AD/DA converting unit 204, and is responsible for sending the digitally quantized ultrasonic reflection echo to the data processing terminal 102 in the form of a wireless electromagnetic wave for analysis and processing; the data storage unit 203 is connected with the AD/DA conversion unit 204 and the transceiving logic unit 201, and is responsible for storing the signal data preprocessed in the data processing terminal 102, and the transceiving logic unit 201 can read the data used therein through a certain flow logic; the AD/DA conversion unit 204 is connected with the power amplification unit 205, the low-noise amplification unit 207, the wireless transmission unit 202 and the data storage unit 203, and is responsible for mutually converting the analog signals converted by the ultrasonic probe and the digital signals which can be identified by the processing chip; the power amplification unit 205 is connected with the non-array ultrasonic probe unit 206 and is responsible for converting the low-voltage signal into a driving signal capable of driving the non-array ultrasonic probe unit 206; the low-noise amplification unit 207 is connected with the non-array ultrasonic probe unit 206 and is responsible for amplifying the electric signals converted by the non-array ultrasonic probe unit 206 through a low-noise amplifier; the non-array ultrasound probe unit 206 is responsible for converting between electrical signals and non-array ultrasound signals, i.e. converting between electrical energy and acoustic energy.
The data processing terminal 102 of the pulse lie detector based on chirp is shown in fig. 4, and is responsible for analyzing and processing data, and includes a signal preprocessing unit 301, a wireless receiving unit 302, and a signal post-processing unit 303. The connection relationship of the components is as follows:
if the data storage unit 203 has no data to store or needs to update the transmitted signal, the signal preprocessing unit 301 is connected with the data storage unit 203 and is responsible for performing predistortion processing on the signal, so that the axial resolution is improved and side lobes are reduced; the wireless receiving unit 302 is connected with the signal post-processing unit 303 and is responsible for receiving ultrasonic echo data from a data acquisition end; the signal post-processing unit 303 is responsible for post-processing the data of the wireless receiving unit 302 to obtain multi-dimensional information such as pulse depth, frequency, amplitude, and the like, so as to provide a more comprehensive reference for determining the lie detection result.
In summary, the above embodiments disclose a pulse lie detection method and apparatus based on chirp, where the sensor uses a non-array ultrasound probe to transmit a chirp continuous signal, and the chirp signal has the advantages of accuracy, multipath resistance, and artifact removal. Combining with pre-distortion processing, pulse compression and layered inversion echo algorithm, and obtaining the position (depth) of each reflecting surface through the time delay between each reflecting echo; inverting the amplitude of the transmitting signal and the amplitude of the echo signal in each reflecting layer by using an attenuation function of ultrasonic waves in a body in an iterative mode, and calculating the reflection coefficient of each reflecting surface; the reflection coefficient can determine the tissue composition of each reflection layer, and obtain multi-dimensional pulse information such as depth, frequency, amplitude and the like of the pulse, so that more dimensional references can be provided for judging lie detection results.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (8)

1. A pulse lie detection method based on linear frequency modulation is characterized by comprising the following steps:
s1, signal preprocessing: adopting a non-array probe to transmit a linear frequency modulation continuous signal, weighting the pulse response of the probe through the amplitude, and finally using a Lanczos window function as an amplitude reduction function to reduce the side lobe after pulse pressure;
s2, pulse compression: performing pulse compression processing on the received reflection echo to obtain narrow pulse with higher peak power; and reducing the side lobe after pulse compression by adding a Hamming window;
s3, layered inversion: by analyzing the time delay information of each reflection echo after pulse compression, reflection coefficients of each reflection layer are inverted, organized reflection coefficients are compared, the position information of the pulse is located, the depth, the frequency, the amplitude and the organization state of the pulse are obtained, and then multi-dimensional lie detection reference information is obtained.
2. The chirp-based pulse lie detection method according to claim 1, wherein the signal preprocessing in step S1 is as follows:
s1.1, determining a signal form, and obtaining an input signal by the input of a user according to the condition that an original signal is a linear frequency modulation signal as follows:
Figure FDA0002251600960000011
wherein f is0Is the center frequency of the signal, K is the signal bandwidth, T is the time width of the signal, a is the amplitude of the signal;
s1.2, amplitude weighting, namely preprocessing the linear frequency modulation by amplitude weighting:
xpre(t)＝Mprob(t)Mdecr(t)x(t),0≤t≤T
wherein M isprob(t) is a probe-based amplitude weighting function;
since the impulse response of the ultrasound probe can be approximated as a cosine wave of the gaussian envelope:
Figure FDA0002251600960000012
wherein, Δ fuIs the bandwidth of the probe, f0Is the center frequency of the probe, μ is a constant; the amplitude weighting function can therefore be expressed as the inverse of a gaussian function:
Figure FDA0002251600960000021
wherein D is a weighting coefficient representing the degree of amplitude weighting;
Mdecr(t) is a Lanczos window function, expressed as follows:
Figure FDA0002251600960000022
wherein the content of the first and second substances,m is the amplitude reduction length.
3. The chirp-based pulse lie detection method according to claim 1, wherein the pulse compression in step S2 is as follows:
s2.1, obtaining an expression of the matched filter according to a criterion of maximizing an output signal-to-noise ratio as follows:
hmatch(t)＝kx*(t0-t)
wherein k is an arbitrary constant, x*Being the conjugate of the chirp signal, t0Is the expected offset;
s2.2, adding a Hamming window function on the basis of the matched filter to obtain an expression of the mismatch filter as follows:
hmismatch(t)＝w(t)hmatch(t)
wherein, the definition of the Hanmming window w (n) is as follows:
Figure FDA0002251600960000024
wherein β is 0.46, and N is the total length of the hamming window;
s2.3, after the reflected echo received by the receiving probe is subjected to pulse compression through a mismatched filter, narrow pulses with higher peak power are obtained:
y(t)＝conv(r(t),F-1(X*(f)Hmismatch(f)))
where r (t) is the reflected echo, F-1For inverse Fourier transform, X*(f) Is the conjugate of the linear frequency-modulated signal after Fourier transform, Hmismatch(f) As a systematic function of the mismatched filter, conv (×) is a convolution operation.
4. The chirp-based pulse lie detection method according to claim 1, wherein the hierarchical inversion in step S3 is as follows:
s3.1, calculating the relative distance of each reflecting layer, and obtaining a time delay result n corresponding to each narrow pulse peak valueiConverting into distance d according to sampling frequency and sound velocityi：
Figure FDA0002251600960000031
Wherein f issIs the system sampling frequency, C is the average speed of sound of the ultrasound in the human tissue, diNamely, the distance of each reflecting surface relative to the skin;
s3.2, obtaining an attenuation function of the ultrasonic signal in the human body by the following formula:
Figure FDA0002251600960000032
wherein, U0Is the initial amplitude of the signal, f is the frequency of the signal, alphaNThe attenuation coefficient of the Nth layer of tissue in the body, and d is the moving distance of the signal in the body;
s3.3, amplitude X of original transmitting signal0Obtaining the amplitude X of the first reflecting layer through the transmission of the known initial reflecting layer and the attenuation function U of the human tissue1：
Figure FDA0002251600960000033
Wherein R is0Is the reflection coefficient of the known initial reflection layer, alpha1Attenuation coefficient, m, from the initial reflective layer to the first reflective layer1＝d1-d0The distance between the first reflecting layer and the initial reflecting layer;
s3.4, reflection echo Y0After attenuation of human tissue and transmission of the known initial reflecting layer, the amplitude Y of the first reflecting layer is obtained1：
Figure FDA0002251600960000034
S3.5, calculating the reflection coefficient of the first layer of reflection layer as follows:
Figure FDA0002251600960000035
wherein, X1Original transmission signal X0Amplitude at the first reflective layer, Y1For reflecting an echo Y0An amplitude at the first reflective layer;
s3.6, and so on, obtaining the amplitude X of the emission signal at the i-th layer reflecting surface through iterationiWith the amplitude Y of the reflected echo signal at the i-th layer reflecting surfacei：
Figure FDA0002251600960000042
Wherein n is the total number of reflecting surfaces, mi＝di-di-1Is the distance between the ith layer and the (i-1) th layer, Ri-1Is the reflection coefficient of the i-1 st layer, alphaiThe attenuation coefficient from the i-1 st layer to the i-th layer is shown;
s3.7, calculating the reflection coefficient of the i-th layer reflection surface as follows:
Figure FDA0002251600960000043
and S3.8, after the reflection coefficients of all layers are obtained, determining the tissue composition of all the reflection layers by comparing the organized reflection coefficients to obtain multi-dimensional information including pulse depth, frequency and amplitude information, thereby providing multi-dimensional pulse reference for judging lie detection results.
5. The chirp-based pulse lie detection method according to claim 2, wherein the value of D is related to the impulse response of the probe, the bandwidth and the time width of the signal.
6. A pulse lie detection device based on linear frequency modulation is characterized by comprising a data acquisition end and a data processing end, wherein the data acquisition end and the data processing end perform information interaction through wireless electromagnetic waves, and the data acquisition end is responsible for receiving and transmitting ultrasonic waves, converting analog signals and digital signals and wirelessly transmitting echo signals; the data processing end is responsible for improving the axial resolution and reducing side lobes through preprocessing of the transmitted signals; and meanwhile, the reflected echo signals are post-processed to obtain multi-dimensional information including pulse depth, frequency and amplitude, so as to provide reference for judging lie detection results.
7. The pulse lie detection device based on chirp according to claim 6, wherein the data acquisition end realizes data acquisition, data forwarding, and time sequence control of a system process, and comprises a transceiving logic unit, a wireless transmitting unit, a data storage unit, an AD/DA conversion unit, a power amplification unit, a non-array ultrasound probe unit, and a low noise amplification unit, and the connection relationship of the components is as follows:
the receiving and transmitting logic unit is respectively connected with the wireless transmitting unit, the data storage unit and the AD/DA conversion unit and is responsible for interval control of transmitted signals and time sequence control of external equipment; the wireless transmitting unit is connected with the AD/DA conversion unit and is responsible for sending the ultrasonic reflection echo after digital quantization to a data processing end in a wireless electromagnetic wave form for analysis and processing; the data storage unit is respectively connected with the AD/DA conversion unit and the transceiving logic unit and is responsible for storing the signal data preprocessed in the data processing end, and the transceiving logic unit reads the data used in the data processing end through the appointed flow logic; the AD/DA conversion unit is respectively connected with the power amplification unit, the low-noise amplification unit, the wireless transmitting unit and the data storage unit and is responsible for mutually converting the analog signals converted by the ultrasonic probe and the digital signals which can be identified by the processing chip; the power amplification unit is connected with the non-array ultrasonic probe unit and is responsible for converting the low-voltage signal into a driving signal for driving the non-array ultrasonic probe unit; the low-noise amplification unit is connected with the non-array ultrasonic probe unit and is responsible for amplifying the electric signals converted by the non-array ultrasonic probe unit through the low-noise amplifier; the non-array ultrasonic probe unit is responsible for realizing the conversion between an electric signal and a non-array ultrasonic signal, namely the conversion between electric energy and acoustic energy.
8. The pulse lie detection device based on chirp according to claim 6, wherein the data processing terminal is responsible for analyzing and processing data, and comprises a signal preprocessing unit, a wireless receiving unit, and a signal post-processing unit, and the connection relationship is as follows:
if the data storage unit does not have data storage or the transmitted signal needs to be updated, the signal preprocessing unit is connected with the data storage unit and is responsible for carrying out predistortion processing on the signal, improving the axial resolution and reducing side lobes; the wireless receiving unit is connected with the signal post-processing unit and is responsible for receiving ultrasonic echo data from the data acquisition end; the signal post-processing unit is responsible for post-processing the data of the wireless receiving unit to obtain multi-dimensional information including pulse depth, frequency and amplitude so as to provide reference for judging lie detection results.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114305225A (en) * 2021-12-31 2022-04-12 福建汉特云智能科技有限公司 Garbage capacity detection method and system for garbage can of sweeping robot

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0240573A1 (en) * 1985-09-27 1987-10-14 Yokogawa Medical Systems, Ltd Ultrasonic wave pulse doppler apparatus
CN101474079A (en) * 2009-01-06 2009-07-08 华南理工大学 Method and device for measuring acoustic impedance of living body based on ultrasound steady state reflection wave
CN204336935U (en) * 2014-12-24 2015-05-20 重庆大学 A kind of multi-path physiology psychological tester based on pulse, breathing and skin resistance
CN105105739A (en) * 2015-04-01 2015-12-02 上海兆观信息科技有限公司 Short-distance wireless heart rate and heart rate variability detection method
CN105338908A (en) * 2013-05-09 2016-02-17 爱飞纽医疗机械贸易有限公司 Ultrasound optimization method and ultrasonic medical device therefor
CN106908768A (en) * 2017-02-24 2017-06-30 四川九洲空管科技有限责任公司 A kind of impulse compression method of ULTRA-LOW SIDE LOBES
CN109106383A (en) * 2017-06-22 2019-01-01 罗杰谊 mood sensing system and method

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0240573A1 (en) * 1985-09-27 1987-10-14 Yokogawa Medical Systems, Ltd Ultrasonic wave pulse doppler apparatus
CN101474079A (en) * 2009-01-06 2009-07-08 华南理工大学 Method and device for measuring acoustic impedance of living body based on ultrasound steady state reflection wave
CN105338908A (en) * 2013-05-09 2016-02-17 爱飞纽医疗机械贸易有限公司 Ultrasound optimization method and ultrasonic medical device therefor
CN204336935U (en) * 2014-12-24 2015-05-20 重庆大学 A kind of multi-path physiology psychological tester based on pulse, breathing and skin resistance
CN105105739A (en) * 2015-04-01 2015-12-02 上海兆观信息科技有限公司 Short-distance wireless heart rate and heart rate variability detection method
CN106908768A (en) * 2017-02-24 2017-06-30 四川九洲空管科技有限责任公司 A kind of impulse compression method of ULTRA-LOW SIDE LOBES
CN109106383A (en) * 2017-06-22 2019-01-01 罗杰谊 mood sensing system and method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114305225A (en) * 2021-12-31 2022-04-12 福建汉特云智能科技有限公司 Garbage capacity detection method and system for garbage can of sweeping robot
CN114305225B (en) * 2021-12-31 2023-02-28 福建汉特云智能科技有限公司 Garbage capacity detection method and system for garbage can of sweeping robot

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