Segmented circular arc arrangement type luggage security check CT detection system and detection device

Abstract

The present application relates to CT detection device, disclose segmented circular arc arrangement type luggage security check CT detection system and detection device, it includes: first group of detector board (31), second group of detector board (32) and third group of detector board (33) are sequentially distributed;First group of detector board (31), second group of detector board (32) and third group of detector board (33) evenly distribute several detector crystals;The receiving surface midpoint of at least one group of detector crystals on the detector board is perpendicular to the receiving surface of the detector crystal with the connecting line of the target center of X-ray source;And the detector crystals of second group of detector board (32) are continuously distributed on the circular arc with the target center of X-ray source (2) as the center of circle.The CT detection system designed by the present application is continuously arranged in the form of circular arc with the target center of X-ray source as the center in the middle part of detection crystal, which is convenient for software algorithm design and improves detection accuracy;The detection crystal on both sides is continuously arranged in the form of circular arc with the center of rotation as the center, which effectively reduces the occupied space of the detector structure and reduces the size of the rotating support.

Description

Technical Field

[0001] This invention relates to CT detection devices, and more particularly to a segmented arc-shaped baggage security inspection CT detection system and detection device. Background Technology

[0002] Computed tomography (CT) is a common transmission imaging technique used in X-ray radiation imaging to scan the interior of luggage and other items, detecting hidden suspected dangerous goods and identifying hazardous substances. In the field of security inspection, the scanning speed directly affects the passage speed and can also increase the scanning speed of security inspection machines while reducing the footprint of the equipment, especially the width of the equipment. These are key factors influencing the widespread application of CT technology in security inspection.

[0003] A typical CT scanner consists of an X-ray source, calibration device, rotating support, detection components, a dedicated computer system for data processing, and a power supply and control system. The main factors affecting CT performance and the overall size of the equipment include the layout of the X-ray source, calibration device, and detection components.

[0004] The precise calculation and design of the X-ray source and detector positions affect the subsequent imaging results and, consequently, the performance of the entire CT equipment. A typical CT design uses the X-ray source target center as the origin and the source-detector distance as the radius to form an arc. The detector crystals are arranged regularly on this arc. Because the distance is constant, the range of X-ray intensity received by the detector at any given moment is relatively consistent, reducing the difficulty of the algorithm.

[0005] For example, in the prior art CN201210350516.X, a baggage CT security inspection system includes: a scanning channel through which baggage enters and exits the baggage CT security inspection system; an X-ray source disposed on one side of the scanning channel; a detection arm disposed on the opposite side of the scanning channel, wherein multiple detector assemblies are mounted on the detection arm, and at least one set of detector crystal receiving surfaces on each of the multiple detector assemblies has its first vertex continuously distributed on an arc centered on the center of the scanning channel, and the multiple detector assemblies are arranged sequentially; and all receiving surfaces of the detector crystals in the multiple detector assemblies are within the range of a radial beam centered on a target point, and in each detector assembly, at least one set of detector crystal receiving surfaces has a line connecting the midpoint of the receiving surface to the X-ray source target point perpendicular to the receiving surface of the detector crystal. Summary of the Invention

[0006] This invention addresses the problems in the prior art by providing a segmented circular arc-shaped baggage security inspection CT detection system and detection device.

[0007] The segmented arc-shaped baggage security CT detection system includes a security CT scanner and a transmission mechanism. The security CT scanner has a through-channel on its side, inside which a rotating bracket equipped with slip rings is rotatably connected. An X-ray source is positioned on the side of the rotating bracket, and a detector bracket is positioned on one side of the rotating bracket opposite the X-ray source. A scanning channel is located inside the rotating bracket, through which the transmission mechanism passes. The X-ray source is fixedly mounted on the rotating bracket. The detector bracket has at least three sets of detector plates segmented into three groups: a first set, a second set, and a third set, arranged sequentially. Multiple detector crystals are evenly distributed across the first, second, and third sets. At least one set of detector crystals on each detector plate has a line connecting the midpoint of its receiving surface to the X-ray source target center perpendicular to the receiving surface. The second set of detector plates is located in the middle of the detector bracket, opposite the X-ray source, and its detector crystals are continuously distributed on an arc centered on the X-ray source target center.

[0008] As a preferred embodiment, the detector crystals of the first and third detector plates are continuously distributed on an arc centered on the center of the scanning channel.

[0009] Preferably, the detector crystal has copper plates alternately arranged on it, and the upper surface of the detector crystal is covered with copper plates to filter out low-energy rays.

[0010] As a preferred option, the minimum angle between the line connecting the X-ray source target center and the midpoint of the detector crystal receiving surface and the receiving surface should be greater than 88°.

[0011] Preferably, the detector crystals are all arranged within the beam range of the X-ray source.

[0012] As a preferred method, the data collected by the detector crystals distributed on the arc centered on the X-ray source target is reconstructed using the first equiangular fan-beam reconstruction method.

[0013] As a preferred method, the data acquired by the detector crystals distributed on the arc centered on the scanning channel center is reconstructed using the second equiangular fan-beam reconstruction method.

[0014] Preferably, the distance between the two detector crystals is no greater than the width of one detector crystal.

[0015] To address the aforementioned technical problems, the present invention also provides a detection device, which includes any of the segmented arc-shaped baggage security inspection CT detection systems described above.

[0016] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The CT detection system designed in this invention has a segmented detector plate, which is designed by combining multiple segments to balance algorithm performance and physical dimensions.

[0017] In the CT detection system of this invention, the detection crystals in the middle part are arranged in a continuous arc shape with the X-ray source target center as the center, which facilitates software algorithm design and improves detection accuracy; the detection crystals on both sides are arranged in a continuous arc shape with the rotation center as the center, which effectively reduces the space occupied by the detector structure and the size of the rotating support. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the CT detector system structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the detector crystal distribution of the present invention.

[0020] Figure 3 This is a schematic diagram of the detector crystal distribution in Embodiment 3 of the present invention.

[0021] Among them, 1—rotating bracket, 2—X-ray source 3—Detector bracket, 31—First group of detector plates, 32—Second group of detector plates 33—Third group of detector plates 4—Scanning Channel 5—The object to be tested. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0023] Example 1 The segmented arc-shaped baggage security CT detection system includes a security CT scanner and a transmission mechanism. The security CT scanner has a through-channel on its side, inside which a rotating bracket 1 equipped with a slip ring is rotatably connected. An X-ray source 2 is located on the side of the rotating bracket 1. A detector bracket 3 is located on one side of the rotating bracket 1, opposite the X-ray source 2. A scanning channel is located inside the rotating bracket 1, through which the transmission mechanism passes. The X-ray source 2 is fixedly mounted on the rotating bracket 1. The detector bracket 3 is segmented with at least three sets of detector plates, namely the first set of detector plates 31, the second set of detector plates 32, the third set of detector plates 33, and the fourth set of detector plates 34. The detector plate 32 and the third detector plate 33 are arranged in sequence, with the first detector plate 31, the second detector plate 32, and the third detector plate 33 distributed sequentially. Several detector crystals are evenly distributed on the first detector plate 31, the second detector plate 32, and the third detector plate 33. At least one set of detector crystals on each detector plate has a line connecting the midpoint of its receiving surface to the X-ray source target center perpendicular to the receiving surface of the detector crystal. The second detector plate 32 is located in the middle of the detector support 3, opposite to the X-ray source 2, and its detector crystals are continuously distributed on an arc centered on the X-ray source target center. This detector distribution combines the X-ray source with various detector arrangement schemes and the geometric relationship between the rotation center and the detector, reducing the size of rotating components such as the detector and the X-ray source while ensuring the quality of the CT reconstructed images.

[0024] The detector crystal has copper plates alternately arranged on it, and the upper surface of the detector crystal is covered with copper plates to filter out low-energy rays.

[0025] The minimum angle between the line connecting the target of X-ray source 2 and the midpoint of the detector crystal receiving surface and the receiving surface should be 89°.

[0026] The detector crystals are all arranged within the beam range of X-ray source 2.

[0027] As a preferred method, the data collected by the detector crystals distributed on the arc centered on the X-ray source target is reconstructed using the first equiangular fan-beam reconstruction method.

[0028] Data collected by detector crystals distributed on an arc centered on the scanning channel center is reconstructed using a second equiangular fan-beam reconstruction method.

[0029] For the second isoangular fan-beam reconstruction method, the algorithm coefficients of the reconstruction data of the first isoangular fan-beam reconstruction method are corrected by rearranging the non-standard circular arcs into standard circular arcs. The specific correction coefficients are calculated by taking the ratio of the distance from X-ray source 2 to the non-standard circular arc detector to the distance from X-ray source 2 to the standard circular arc detector.

[0030] The distance between two detector crystals is no greater than the width of one detector crystal.

[0031] It also includes a control board, which controls the first group of detector boards 31, the second group of detector boards 32 and the third group of detector boards 33 in a unified manner.

[0032] Example 2 The segmented arc-shaped baggage security CT detection system includes a security CT scanner and a transmission mechanism. The security CT scanner has a through-channel on its side, inside which a rotating bracket 1 equipped with a slip ring is rotatably connected. An X-ray source 2 is located on the side of the rotating bracket 1. A detector bracket 3 is located on one side of the rotating bracket 1, opposite the X-ray source 2. A scanning channel is provided inside the rotating bracket 1, through which the transmission mechanism passes. The X-ray source 2 is fixedly mounted on the rotating bracket 1. The detector bracket 3 has at least three sets of detector plates, namely a first set of detector plates 31, a second set of detector plates 32, a third set of detector plates 33, and a fourth set of detector plates 34. The detector plate 32 and the third detector plate 33 are arranged in sequence; the first detector plate 31, the second detector plate 32 and the third detector plate 33 are arranged in sequence; the first detector plate 31, the second detector plate 32 and the third detector plate 33 have several detector crystals evenly distributed; at least one set of detector crystals on the detector plate has a line connecting the midpoint of the receiving surface of the receiving surface of the detector crystal to the center of the X-ray source target perpendicular to the receiving surface of the detector crystal; the second detector plate 32 is located in the middle of the detector support 3 and is set opposite to the X-ray source 2, and the detector crystals of the second detector plate 32 are continuously distributed on an arc centered on the center of the X-ray source 2 target.

[0033] The detector crystals of the first group of detector plates 31 and the third group of detector plates 33 are continuously distributed on an arc centered on the center of the scanning channel.

[0034] The detector crystal has copper plates alternately arranged on it, and the upper surface of the detector crystal is covered with copper plates to filter out low-energy rays.

[0035] The minimum angle between the line connecting the target point of X-ray source 2 and the midpoint of the detector crystal receiving surface and the receiving surface should be 89.5°.

[0036] The detector crystals are all arranged within the beam range of X-ray source 2.

[0037] Data collected by detector crystals distributed on an arc centered on the X-ray source is reconstructed using the first equiangular fan-beam reconstruction method.

[0038] Data collected by detector crystals distributed on an arc centered on the scanning channel center is reconstructed using a second equiangular fan-beam reconstruction method.

[0039] The distance between two detector crystals is equal to the width of one detector crystal.

[0040] By setting the distance between the detector crystals, data can be detected effectively.

[0041] Example 3 Based on Example 2, this example sets the second group of detector boards 32 according to the diameter of the detection scanning channel. During the setting process, the detection accuracy of the detector needs to be considered and the setting should be based on the customer's detection range.

[0042] This embodiment Figure 3 In the diagram, the scanning channel and the object to be tested are shown. The size of the scanning channel can be set according to the customer. In the diagram, the size of the scanning channel is 600mm*400mm, and the objects to be tested in the usage scenario are mostly ordinary luggage packages. The commonly used detection range for luggage packages is K; the area of ​​the scanning channel is S1; the area size is 0.24 square meters; the four corners of the scanning channel 4 are not the key areas of the package to be inspected. A standard arc detector arrangement is used for the key areas of the package to be inspected, while a non-standard arc arrangement is used for the non-key areas; the area corresponding to the key areas of the package to be inspected is set to K*S1; assuming that the commonly used detection range of luggage packages is 80% here, the area corresponding to the detection area is 0.8S1; in the diagram, this is b0b1c0c1, which together form an area of ​​0.8S1; and b0 and c0 are symmetrically distributed on the central axis corresponding to the center of the circle with the target center of X-ray source 2 as the center; b1 and c1 are symmetrically distributed on the central axis corresponding to the target center of X-ray source 2 as the center. Similarly, for the ray with b0b1 as the target of X-ray source 2, the point where the ray intersects with the detector plate is b2; for the ray with c0c1 as the target of X-ray source 2, the point where the ray intersects with the detector plate is c2; the distance between b2 and c2 is the length of the second set of detector plates 32.

[0043] The length and position of the second set of detector plates 32 can be determined based on the above for detector ranges with different requirements. A standard arc detector arrangement is used for key areas of the package to be inspected, while a non-standard arc arrangement is used for non-key areas. This effectively ensures the detection accuracy of the package to be inspected while also reducing the overall size of the equipment.

[0044] Example 4 Based on the above embodiments, this embodiment provides a detection device, which includes a segmented arc-shaped baggage security inspection CT detection system.

Claims

1. A segmented arc-shaped baggage security inspection CT detection system, comprising a security inspection CT machine and a transmission mechanism, wherein the security inspection CT machine has a through channel on its side, and a rotating bracket (1) with a slip ring is rotatably connected inside the through channel, and an X-ray source (2) is provided on the side of the rotating bracket (1), and a detector bracket (3) is provided on one side of the rotating bracket (1) opposite to the X-ray source (2), a scanning channel is provided inside the rotating bracket (1), the transmission mechanism passes through the scanning channel, and the X-ray source (2) is fixedly installed on the rotating bracket (1), characterized in that, The detector support (3) is divided into sections with at least three sets of detector plates, namely the first set of detector plates (31), the second set of detector plates (32) and the third set of detector plates (33); and the first set of detector plates (31), the second set of detector plates (32) and the third set of detector plates (33) are distributed in sequence; the first set of detector plates (31), the second set of detector plates (32) and the third set of detector plates (33) are evenly distributed with arrays of detector crystals; at least one set of detector crystals on the detector plate has a line connecting the midpoint of the receiving surface of the receiving surface of the receiving surface of the detector crystal perpendicular to the X-ray source target center; the second set of detector plates (32) is located in the middle of the detector support (3) and is set opposite to the X-ray source (2), and the detector crystals of the second set of detector plates (32) are continuously distributed on an arc with the X-ray source (2) target center as the center.

2. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The detector crystals of the first group of detector plates (31) and the third group of detector plates (33) are continuously distributed on an arc centered on the center of the scanning channel.

3. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The detector crystal has copper plates alternately arranged on it, and the upper surface of the detector crystal is covered with copper plates to filter out low-energy rays.

4. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The minimum angle between the line connecting the target center and the midpoint of the detector crystal receiving surface of the X-ray source (2) and the receiving surface should be greater than 88°.

5. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The detector crystals are all arranged within the beam range of the X-ray source (2).

6. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The data collected by the detector crystals distributed on the arc centered on the X-ray source (2) target are reconstructed by the first equal-angle fan-beam reconstruction method.

7. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: Data collected by detector crystals distributed on an arc centered on the scanning channel center is reconstructed using a second equiangular fan-beam reconstruction method.

8. The segmented arc-shaped baggage security inspection CT detection system according to claim 1, characterized in that: The distance between two detector crystals is no greater than the width of one detector crystal.

9. A detection device, characterized in that, The segmented arc-shaped baggage security inspection CT detection system as described in any one of claims 1-8.

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