A method for reducing the influence of wave-transmitting materials on millimeter wave imaging

Abstract

The present invention provides a method for reducing the impact of wave-transmitting materials on millimeter-wave imaging, comprising the following steps: S1, acquiring air-sampled data using millimeter-wave equipment; S2, pulse compressing the echo data; S3, determining the influence factor of the wave-transmitting material on the millimeter-wave imaging area; S4, performing pulse cancellation; and S5, performing millimeter-wave imaging. The method for reducing the impact of wave-transmitting materials on millimeter-wave imaging described in the present invention can reduce the impact of factors such as the material properties of the wave-transmitting material and vibration of the wave-transmitting material caused by equipment during security inspections on image quality, thereby improving millimeter-wave image quality, increasing the accuracy of intelligent millimeter-wave image recognition, reducing the false detection rate, and effectively enhancing the stability and reliability of security inspections.

Description

Technical Field

[0001] The present invention relates to the field of imaging technology, and in particular to a method for reducing the influence of wave-transmitting materials on millimeter wave imaging. Background Art

[0002] Millimeter-wave imaging technology is currently widely used in the field of human security inspections. Millimeter-wave equipment used for human security inspections is primarily categorized by scanning method: mechanical scanning and electronic scanning. Regardless of the scanning method used, the person being inspected must remain stationary within the device until the scan is complete. From a safety perspective, during mechanical scanning, the millimeter-wave antenna, driven by a servo mechanism, moves at high speed. To prevent accidental injury to the human body during antenna movement, a wave-transparent material such as acrylic or PVC must be installed between the antenna and the body to isolate the person being inspected from the antenna. From a psychological perspective, the person being inspected must be unable to look directly at the millimeter-wave array antenna to reduce their resistance to inspection. From a structural perspective, a support structure is required to house a diagram of the person being inspected, guiding them through the inspection process. However, the introduction of wave-transparent materials can negatively impact millimeter-wave imaging, reducing image quality. Summary of the Invention

[0003] The present invention aims to overcome the technical problem in the prior art that transparent materials can reduce the imaging quality during millimeter wave imaging, and provides a method for reducing the influence of transparent materials on millimeter wave imaging. The method can reduce the influence of factors such as the material properties of the transparent materials themselves and the vibration of the transparent materials caused by the equipment during security inspection on the image quality, improve the quality of millimeter wave images, increase the accuracy of intelligent recognition of millimeter wave images, reduce the false detection rate, and effectively improve the stability and reliability of security inspections.

[0004] The present invention provides a method for reducing the influence of wave-transmitting materials on millimeter wave imaging, comprising the following steps:

[0005] S1. Millimeter wave equipment acquires empty data: The millimeter wave equipment collects data when there are no people being inspected inside, obtaining the original millimeter wave echo data of security inspection imaging;

[0006] S2. Echo data pulse compression: Pulse compression is performed on the original echo data to obtain the range and phase information of the original echo data;

[0007] S3. Determine the influence factor of the wave-transmitting material on the millimeter-wave imaging area: determine the distance range between the wave-transmitting material area and the imaging area, establish a matrix relationship between the wave-transmitting material area and the imaging area, and transform the matrix relationship to reduce the matrix dimension to obtain the influence factor;

[0008] S4. Pulse cancellation: Remove the coupling effect of the wave-transmitting material on the imaging area by cancellation to obtain the distance phase information of the imaging area;

[0009] S5. Millimeter wave imaging: Perform millimeter wave imaging on the distance and phase information of the imaging area.

[0010] In the method for reducing the influence of wave-transmitting materials on millimeter wave imaging described in the present invention, as a preferred embodiment, step S3 further includes the following steps:

[0011] S31, determine the distance phase range between the wave-transmitting material area and the imaging area, and determine the distance phase range of the wave-transmitting material area to be 5≤L by the distance between the wave-transmitting material and the imaging area and the millimeter wave antenna. B <5+n, total n points; the imaging area is 20≤L from the phase area point A <20+m, total m points;

[0012] S32. Introduce all the scan amount information in the entire rotation scanning cycle and establish a matrix relationship A=αB between the wave-transmitting material area and the imaging area, where A is m×k, α is an m×n matrix, and B is an n×k matrix:

[0013]

[0014] Where k is the number of scans, m is the number of points in the distance area, and n is the number of points in the wave-transmitting material area;

[0015] S33. Solve the impact factor α

[0016] α=AB H (BB H ) -1

[0017] Among them: B H is the conjugate transposed matrix of matrix B, and α is the influence factor.

[0018] The method of reducing the influence of wave-transmitting materials on millimeter wave imaging described in the present invention is, as a preferred embodiment, a method for removing the coupling influence of the wave-transmitting materials on the imaging area in step S4 as follows:

[0019] A1=A0-αB0

[0020] Among them: A1 is the distance phase information of the imaging area after removing the coupling relationship, A0 is the original distance phase information of the imaging area, α is the influence factor, and B0 is the original distance phase information of the wave-transmitting material area.

[0021] The advantages of the present invention are:

[0022] (1) This method solves the influence factor of the wave-transmitting material on the millimeter wave imaging area, reduces the influence of the wave-transmitting material on the millimeter wave imaging, improves the quality of the millimeter wave image, increases the accuracy of the intelligent recognition of the millimeter wave image, reduces the false detection rate, and effectively improves the reliability of the millimeter wave security inspection.

[0023] (2) Using the echo data within the full scanning cycle as the input condition can effectively reduce the image quality problem caused by the vibration of the wave-transmitting material, and the algorithm has strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a method for reducing the influence of wave-transmitting materials on millimeter-wave imaging;

[0025] Figure 2 This is a comparison diagram before and after the air sampling imaging of Example 1;

[0026] Figure 3 This is a comparison diagram of the human body before and after imaging in Example 1. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] Example 1

[0029] like Figure 1 As shown, a method for reducing the influence of wave-transmitting materials on millimeter wave imaging includes the following steps:

[0030] S1. Millimeter wave equipment acquires empty data: The millimeter wave equipment collects data when there are no people being inspected inside, obtaining the original millimeter wave echo data of security inspection imaging;

[0031] S2. Echo data pulse compression: Pulse compression is performed on the original echo data to obtain the range and phase information of the original echo data;

[0032] S3. Determine the influence factor of the wave-transmitting material on the millimeter wave imaging area: determine the distance range between the wave-transmitting material area and the imaging area, establish a matrix relationship between the wave-transmitting material area and the imaging area, and transform the matrix relationship to reduce the matrix dimension to obtain the influence factor; step S3 further includes the following steps:

[0033] S31, determine the distance phase range between the wave-transmitting material area and the imaging area, and determine the distance phase range of the wave-transmitting material area to be 5≤L by the distance between the wave-transmitting material and the imaging area and the millimeter wave antenna. B <5+n, total n points; the imaging area is 20≤L from the phase area point A <20+m, with a total of m points, in this embodiment, k=300, m=40, n=10;

[0034] S32. Introduce all the scan amount information in the entire rotation scanning cycle and establish a matrix relationship A=αB between the wave-transmitting material area and the imaging area, where A is m×k, α is an m×n matrix, and B is an n×k matrix:

[0035]

[0036] Where k is the number of scans, m is the number of points in the distance area, and n is the number of points in the wave-transmitting material area;

[0037] S33. Solve the impact factor α

[0038] A=αB

[0039] Multiply right by the inverse matrix B -1 ;

[0040] α=AB -1

[0041] In view of the fact that the number of scans k in actual use is greater than the range of points n in the wave-transmitting material distance phase region, in order to reduce the amount of calculation for solving the inverse matrix of the n×k matrix, the matrix dimension is reduced by matrix transformation. After the matrix transformation, only BB needs to be solved. H The inverse of the matrix, the matrix size is n×n;

[0042] α=AB H (B H ) -1 B -1

[0043] α=AB H (BB H ) -1

[0044] Among them: B H is the conjugate transposed matrix of matrix B, and α is the impact factor;

[0045] S4, pulse cancellation: The coupling effect of the wave-transmitting material on the imaging area is removed by cancellation to obtain the distance phase information of the imaging area. The method for removing the coupling effect of the wave-transmitting material on the imaging area in step S4 is as follows:

[0046] A1=A0-αB0

[0047] Where: A1 is the distance phase information of the imaging area after removing the coupling relationship, A0 is the original distance phase information of the imaging area, α is the influence factor, and B0 is the original distance phase information of the wave-transmitting material area;

[0048] S5. Millimeter wave imaging: Perform millimeter wave imaging on the distance and phase information of the imaging area.

[0049] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for reducing the influence of wave-transmitting materials on millimeter wave imaging, characterized by: The following steps are involved: S1. The millimeter wave device acquires empty data: The millimeter wave device collects data when there is no person being inspected inside, and obtains security inspection imaging millimeter wave raw echo data; S2. Echo data pulse compression: performing pulse compression on the original echo data to obtain range and phase information of the original echo data; S3. Determine the influence factor of the wave-transmitting material on the millimeter wave imaging area: determine the distance range between the wave-transmitting material area and the imaging area, establish a matrix relationship between the wave-transmitting material area and the imaging area, and transform the matrix relationship to reduce the matrix dimension to obtain the influence factor; Step S3 further includes the following steps: S31, determine the distance phase range between the wave-transmitting material area and the imaging area, and determine the distance phase range of the wave-transmitting material area to be 5≤L by the distance between the wave-transmitting material and the imaging area and the millimeter wave antenna. B <5+n, total n points; the imaging area is 20≤L from the phase area point A <20+m, total m points; S32. Introduce all the scan amount information in the entire rotation scanning cycle and establish a matrix relationship A=αB between the wave-transparent material area and the imaging area, where A is an m×k matrix, α is an m×n matrix, and B is an n×k matrix: Where k is the number of scans, m is the number of points in the imaging area, and n is the number of points in the wave-transmitting material area; S33. Solve the impact factor α α=AB H (BB H ) -1 Among them: B H is the conjugate transposed matrix of matrix B, α is the impact factor; S4. Pulse cancellation: Remove the coupling effect of the wave-transmitting material on the imaging area by cancellation to obtain the distance phase information of the imaging area; S5. Millimeter wave imaging: performing millimeter wave imaging on the distance and phase information of the imaging area.

2. The method of reducing the influence of wave-transmitting materials on millimeter wave imaging according to claim 1, characterized in that: The method for removing the coupling effect of the wave-transmitting material on the imaging area in step S4 is as follows: A1=A0-αB0 Wherein: A1 is the distance phase information of the imaging area after removing the coupling relationship, A0 is the original distance phase information of the imaging area, α is the influence factor, and B0 is the original distance phase information of the wave-transmitting material area.

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