阅读说明：本技术 一种带有运动补偿的安检成像系统及其使用方法 (Security inspection imaging system with motion compensation and using method thereof ) 是由 任百玲 孙兆阳 朱明� 周利苹 许戎戎 刘昊 于 2020-05-20 设计创作，主要内容包括：本发明提供的一种带有运动补偿的安检成像系统,包括信号收发模块(1)、加速度检测模块(2)、动力模块(3)、悬臂(4)和处理器(5),信号收发模块(1)竖向设置于悬臂(4)下表面,动力模块(3)设置于悬臂(4)上端,加速度检测模块(2)设置于信号收发模块(1)下端,处理器(5)与加速度检测模块(2)、信号收发模块(1)电连接。本发明通过在天线悬臂上安装加速度传感器的方式,通过圆周运动过程中不断的径向加速度测量获得悬臂的实时加速度,再通过加速度获得径向距离偏移,滤掉高频和低频相位误差后,从而获得相位晃动补偿误差项。(The invention provides a security inspection imaging system with motion compensation, which comprises a signal transceiving module (1), an acceleration detection module (2), a power module (3), a cantilever (4) and a processor (5), wherein the signal transceiving module (1) is vertically arranged on the lower surface of the cantilever (4), the power module (3) is arranged at the upper end of the cantilever (4), the acceleration detection module (2) is arranged at the lower end of the signal transceiving module (1), and the processor (5) is electrically connected with the acceleration detection module (2) and the signal transceiving module (1). According to the invention, by mounting the acceleration sensor on the antenna cantilever, the real-time acceleration of the cantilever is obtained through continuous radial acceleration measurement in the circular motion process, then the radial distance offset is obtained through the acceleration, and after high-frequency and low-frequency phase errors are filtered, a phase shake compensation error term is obtained.)

1. A security imaging system with motion compensation, comprising: including signal transceiver module (1), acceleration detection module (2), power module (3), cantilever (4) and treater (5), signal transceiver module (1) vertical set up in cantilever (4) lower surface is used for the transmission and receives the millimeter wave, power module (3) set up in cantilever (4) upper end is used for making cantilever (4) are connected and rotatable with the inside top of the human safety inspection appearance of millimeter wave, acceleration detection module (2) set up in signal transceiver module (1) lower extreme is used for detect the rotatory acceleration of signal transceiver module (1), treater (5) with acceleration detection module (2) signal transceiver module (1) electricity is connected and is used for handling echo signal and deriving three-dimensional imaging result.

2. A security imaging system with motion compensation as claimed in claim 1, wherein: the signal transceiving module (1) comprises a first signal receiving module (11) and a second signal receiving module (12), and the first signal receiving module (11) and the second signal receiving module (12) are arranged at the lower end of the cantilever (4) relatively.

3. A security imaging system with motion compensation as claimed in claim 2, wherein: the acceleration detection module (2) comprises a first acceleration sensor (21) and a second acceleration sensor (22), the first acceleration sensor (21) is arranged at the lower end of the first signal receiving module (11), and the second acceleration sensor (22) is arranged at the lower end of the second signal receiving module (12).

4. A security imaging system with motion compensation as claimed in claim 1, wherein: and the rotating shaft of the power module (3) is vertical to the top end inside the millimeter wave human body security inspection instrument.

5. A security imaging system with motion compensation as claimed in claim 1, wherein: the processor (5) comprises an acceleration shake compensation module (51) and a three-dimensional imaging module (52), wherein the three-dimensional imaging module (52) is connected with the acceleration shake compensation module (51) and the signal transceiving module (1) and is used for processing the echo signals into three-dimensional images; the acceleration shake compensation module (51) is connected with the three-dimensional imaging module (52) and the acceleration detection module (2) and is used for obtaining shake error signals through the acceleration detected by the acceleration detection module (2) and carrying out shake compensation on the three-dimensional image.

6. The use of a security imaging system with motion compensation as claimed in claim 5, wherein: the method comprises the following steps:

s1, the antenna array of the millimeter wave human body security check instrument cantilever (4) rotates through the cantilever (4) to start detection;

s2, the signal transceiving module (1) generates millimeter wave signals for detection;

s3, the first acceleration sensor (21) and the second acceleration sensor (22) work to detect the acceleration a of the rotation_m′；

S4, the first signal receiving module (11) and the second signal receiving module (12) receive the echo signals reflected by the human body;

s5, extracting shake compensation signals by the acceleration shake compensation module (51), and simultaneously carrying out two-dimensional Fourier transform on the echo signals by the three-dimensional imaging module (52);

s6, performing weighted shaking compensation on the echo signal after image enhancement and denoising by using the shaking compensation signal;

and S7, obtaining a three-dimensional imaging result through an azimuth one-dimensional BP imaging algorithm.

7. The use of a security imaging system with motion compensation as claimed in claim 6, wherein: in step S5, the specific step of extracting the shake compensation signal by the acceleration shake compensation module (51) includes:

s51, acceleration a during rotation measured by the first acceleration sensor (21) and the second acceleration sensor (22)_m′Wherein the value range of M' is 1-M, M is the number of angles for starting and transmitting the system, and the acceleration shaking compensation module (51) can measure the angular speed omega of rotation_m′The formula is as follows:

a_m′＝ω_m′ ²r_m′；

wherein the acceleration a_m′Angular velocity ω_m′，r_m′Is the diameter, preSet the radius of rotation to be r₀；

ΔR＝r_m′-r₀；

Where c is the speed of light, f is the operating frequency, Δ R is the position offset;

s52, setting an intermediate frequency component as a phase generated by the swinging of the cantilever (4) array, setting a signal form corresponding to the phase phi as exp (j phi), filtering the signal form of the phase phi to filter a low-frequency component and a high-frequency component, and obtaining a phase-compensated signal form exp (j phi') after filtering;

obtaining a shake compensation signal due to a position offset from the acceleration,

s″＝exp(jΦ)

where s "is the error phase signal,

and performing middle-pass filtering on the obtained error phase signal, filtering out high-frequency and low-frequency phase terms, and obtaining a filtered shake compensation signal s'.

s″′＝exp(jΦ′)

Where Φ' is the phase after filtering out the high and low frequency signals.

8. The use of a security imaging system with motion compensation as claimed in claim 7, wherein: in step S5, the specific step of performing two-dimensional fourier transform on the echo signal by the three-dimensional imaging module (52) includes:

s53, Fourier transform of the echo signals along the elevation direction: let the position coordinates of the cylindrical antenna array be (r sin theta, y, r cos theta), and the position of the target be (x)_i,y_i,z_i) The form of the target echo signal is as follows:

where r is the scanning radius of the antenna array, k is the wave number,

and Fourier transform is carried out on the echo signals along the elevation direction to obtain:

s54, multiplying the echo signals after Fourier transform along the elevation direction by a matched filter term, wherein the matched filter term is

wherein k is_yWave number in y direction;

and S55, distance interpolation: will be in step S54Interpolate to 2k, get the formula:

s56, performing two-dimensional inverse Fourier transform on the S2 to obtain a YZ dimension slice imaging result:

wherein k is_cThe central wavenumber.

9. The use of a security imaging system with motion compensation as claimed in claim 6, wherein:

the step S6 specifically includes:

s61, obtaining a shake error signal A (h) exp (j phi ') through the shake compensation signal exp (j phi');

wherein A (H) is a compensation coefficient, H belongs to [1, H ];

s62, compensating the shaking error signal for S ', namely multiplying S' by the complex conjugate of the shaking error signal, wherein the formula is as follows:

10. the use of a security imaging system with motion compensation as claimed in claim 6, wherein: the specific method of step S7 is: and obtaining an imaging result formula by passing the echo signal after the shake compensation through a one-dimensional BP (back propagation) method, wherein the formula is as follows:

S″″′＝(z-z_i)(x-x_i)(y-y_i)。

Technical Field

The invention mainly relates to the field of security detection, in particular to a security inspection imaging system with motion compensation and a security inspection imaging method with motion compensation.

Background

The traditional metal detector can only detect metal contraband and has no effect on plastic bombs and ceramic cutters; although the X-ray security inspection equipment can detect all prohibited articles, the X-ray security inspection equipment has certain threat to human health and is not an optimal security inspection means. The existing millimeter wave three-dimensional imaging technology is an effective method for replacing the traditional security inspection means.

The existing millimeter wave human body security inspection instrument adopts a cantilever mode to install an antenna array. The lower end of the cantilever antenna array is not supported, and the cantilever shakes when the antenna array rotates. This shaking tends to cause incoherent motion between the human body and the antenna array, causing blurring of the image.

Disclosure of Invention

The invention provides a security inspection imaging system with motion compensation and a using method thereof, aiming at solving the problem that imaging blurring is caused by the fact that a cantilever shakes when an antenna array rotates in the prior art, the problem is solved by obtaining real-time acceleration of the cantilever through continuous radial acceleration measurement in the circular motion process by installing an acceleration sensor on the antenna cantilever, obtaining radial distance offset through the acceleration, and obtaining a phase shake compensation error term after filtering out high-frequency and low-frequency phase errors.

The invention provides a security check imaging system with motion compensation, which comprises a signal transceiving module, an acceleration detection module, a power module, a cantilever and a processor, wherein the signal transceiving module is vertically arranged on the lower surface of the cantilever and used for transmitting and receiving millimeter waves, the power module is arranged at the upper end of the cantilever to enable the cantilever to be connected with the top end inside a millimeter wave human body security check instrument and to be rotatable, the acceleration detection module is arranged at the lower end of the signal transceiving module and used for detecting the rotation acceleration of the signal transceiving module, and the processor is electrically connected with the acceleration detection module and the signal transceiving module and used for processing echo signals and obtaining a three-dimensional imaging result.

According to the technical scheme, the real-time acceleration of the cantilever is obtained through continuous radial acceleration measurement in the circumferential motion process in a mode of installing the acceleration sensor on the antenna cantilever, then the radial distance offset is obtained through the acceleration, and after high-frequency and low-frequency phase errors are filtered, a phase shake compensation error term is obtained. The shaking error term is compensated for in subsequent imaging processes. Therefore, imaging blurring caused by incoherent motion between a human body and the antenna array is reduced, and imaging quality of the image is improved. The power device is a servo motor and is driven by the servo motor to do circular motion, and the range of the circular motion is about 100-130 degrees.

As a preferred mode, the signal receiving and transmitting module comprises a first signal receiving module and a second signal receiving module, and the first signal receiving module and the second signal receiving module are oppositely arranged at the lower end of the cantilever.

According to the security inspection imaging system with motion compensation, as a preferable mode, the acceleration detection module comprises a first acceleration sensor and a second acceleration sensor, the first acceleration sensor is arranged at the lower end of the first signal receiving module, and the second acceleration sensor is arranged at the lower end of the second signal receiving module.

As an optimal mode, the rotating shaft of the power module is arranged perpendicular to the top end inside the millimeter wave human body security inspection instrument.

The invention relates to a security check imaging system with motion compensation, as an optimal mode, a processor comprises an acceleration shaking compensation module and a three-dimensional imaging module, wherein the three-dimensional imaging module is connected with the acceleration shaking compensation module and a signal transceiving module and is used for processing echo signals into three-dimensional images; the acceleration shake compensation module is connected with the three-dimensional imaging module and the acceleration detection module and used for obtaining shake error signals through the acceleration detected by the acceleration detection module and carrying out shake compensation on the three-dimensional image.

The invention provides a use method of a security check imaging system with motion compensation, which comprises the following steps:

s1, the millimeter wave human body security check instrument cantilever antenna array starts to detect through cantilever rotation;

s2, generating millimeter wave signals for detection by the signal transceiving module;

s3, the first acceleration sensor and the second acceleration sensor work to measure the acceleration a of the rotation_m′；

S4, the first signal receiving module and the second signal receiving module receive echo signals reflected by the human body;

s5, extracting a shake compensation signal by the acceleration shake compensation module, and simultaneously carrying out two-dimensional Fourier transform on an echo signal by the three-dimensional imaging module;

s6, weighting and shaking compensation are carried out on the echo signals after image enhancement and denoising by using the shaking compensation signals;

and S7, obtaining a three-dimensional imaging result through an azimuth one-dimensional BP imaging algorithm.

The use method of the security inspection imaging system with motion compensation, which is provided by the invention, is a preferable mode, and the specific steps of extracting the shake compensation signal by the acceleration shake compensation module in the step S5 comprise:

s51, acceleration a during rotation measured by the first acceleration sensor and the second acceleration sensor_m′Wherein the value range of M' is 1-M, M is the number of angles for starting and transmitting the system, and the acceleration is realizedThe angular velocity omega of rotation can be measured by the degree shake compensation module_m′The formula is as follows:

a_m′＝ω_m′ ²r_m′；

wherein the acceleration a_m′Angular velocity ω_m′，r_m′Is the diameter, the predetermined radius of rotation is r₀；

ΔR＝r_m′-r₀；

Where c is the speed of light, f is the operating frequency, Δ R is the position offset;

s52, setting the intermediate frequency component as a phase generated by cantilever array shaking, and performing filtering processing on the signal form of the phase phi to filter out a low-frequency component and a high-frequency component, wherein the signal form corresponding to the phase phi is exp (j phi), and the signal form of phase compensation exp (j phi') is obtained after filtering;

a shake compensation signal due to the positional deviation is obtained from the acceleration,

s″＝exp(jΦ)

where s "is the error phase signal,

and performing middle-pass filtering on the obtained error phase signal, filtering high-frequency and low-frequency phase terms, and obtaining a filtered shake compensation signal s'.

s″′＝exp(jΦ′)

Where Φ' is the phase after filtering out the high and low frequency signals.

An acceleration sensor mounted under the antenna cantilever for measuring the acceleration a during rotation_m′Wherein the value range of M' is 1-M, and M is the number of angles for starting and transmitting the system. The angular speed omega of the rotation can be measured by an encoder_m′. Low-frequency component is system installation error, high-frequency component is noise, medium-frequency component is phase position produced by cantilever array shaking, signal form corresponding to phase position phi is exp (j phi), filtering processing is carried out on the signal form to filter low-frequency component and high-frequency component, and the filtering wave form can be FIR filtering, Fourier transformOne of transform filtering and polynomial filtering. After filtering, the phase compensated signal form exp (j Φ') is obtained.

The use method of the security check imaging system with motion compensation, which is provided by the invention, is taken as an optimal mode, and the specific steps of performing two-dimensional Fourier transform on an echo signal by a three-dimensional imaging module in the step S5 comprise:

s53, Fourier transform is carried out on the echo signals along the elevation direction: let the position coordinates of the cylindrical antenna array be (rsin theta, y, r cos theta) and the position of the target be (x)_i,y_i,z_i) The form of the target echo signal is:

where r is the scanning radius of the antenna array, k is the wave number,

f is the working frequency of the system, and c is the speed of light;

performing elevation direction Fourier transform on the echo signals to obtain:

s54, multiplying the echo signals after Fourier transform along the elevation direction by a matched filter termThe following formula is obtained:

wherein k is_yWave number in y direction;

and S55, distance interpolation: will be in step S54Interpolate to 2k, get the formula:

s56, performing two-dimensional inverse Fourier transform on the S2 to obtain a YZ dimension slice imaging result:

wherein k is_cThe central wavenumber.

The imaging algorithm in the processor adopts an algorithm combining Fourier transform (FFT), BP algorithm and wave number domain algorithm.

As a preferred mode, the step S6 of using the security imaging system with motion compensation of the present invention specifically includes:

s61, obtaining a shake error signal A (h) exp (j phi ') through the shake compensation signal exp (j phi');

wherein A (H) is a compensation coefficient, H belongs to [1, H ];

s62, compensating the shaking error signal for S ', namely multiplying S' by the complex conjugate of the shaking error signal, wherein the formula is as follows:

the compensation phase extracted by the antenna array unit at the lowest end is gradually reduced due to the compensation coefficient from bottom to top, so that the compensation phase is multiplied by the corresponding compensation coefficient A (h)

The use method of the security check imaging system with motion compensation in the invention is a preferable mode, and the specific method of the step S7 is as follows: and (3) obtaining an imaging result formula by passing the echo signal after the shake compensation through the one-dimensional BP, wherein the imaging result formula is as follows:

S″″′＝(z-z_i)(x-x_i)(y-y_i)

firstly, Fourier transform is carried out on echo signals along the elevation direction; then multiplying the signals subjected to Fourier transform in the elevation direction by a matched filtering function to obtain echo signals subjected to matched filtering; interpolating the matched and filtered signals in the distance direction; fourier transform is carried out on the signals after interpolation in two dimensions in the distance direction, and echo signals after two-dimensional Fourier transform are obtained; multiplying the echo signal after the two-dimensional Fourier transform by the complex conjugate of the shaking error signal A (h) exp (j phi') with weighting coefficients; and finally, obtaining a three-dimensional imaging result through the orientation dimension BP.

The invention has the following beneficial effects:

(1) by adding a shaking phase compensation step in the algorithm flow, the problem of image blurring caused by shaking is solved;

(2) the real-time acceleration of the cantilever is obtained through continuous radial acceleration measurement in the circular motion process, then the radial distance offset is obtained through the acceleration, and after high-frequency and low-frequency phase errors are filtered out, a phase shake compensation error term is obtained, and the shake error term is compensated in the subsequent imaging process. Therefore, imaging blurring caused by incoherent motion between a human body and the antenna array is reduced, and imaging quality of the image is improved.

Drawings

FIG. 1 is a schematic diagram of a security imaging system with motion compensation;

FIG. 2 is a schematic diagram of a signal transceiver module of a security imaging system with motion compensation;

FIG. 3 is a schematic diagram of an acceleration detection module of a security imaging system with motion compensation;

FIG. 4 is a schematic diagram of a security imaging system processor with motion compensation;

fig. 5 is a flow chart of a method of using a security imaging system with motion compensation.

Reference numerals:

1. a signal transceiving module; 11. a first signal receiving module; 12. a second signal receiving module; 2. an acceleration detection module; 21. a first acceleration sensor; 22. a second acceleration sensor; 3. a power module; 4. a cantilever; 5. a processor; 51. an acceleration shake compensation module; 52. a three-dimensional imaging module.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.