A backscattering imaging device and a backscattering detection system

Abstract

The present invention provides a backscatter imaging device and a backscatter imaging system. The chopper collimator of the backscatter imaging device includes a plurality of chopper slits arranged along the first side direction. The chopper slits perform reciprocating linear motion and overlap with the pre-slit to form a flying spot. Compared with the chopper slits that perform circular motion in the prior art, it has many advantages. The speeds of the chopper slits in linear motion are the same everywhere. Therefore, the exposure time is constant during the intersection with the pre-slit, and there will be no difference in the intensity of exposure. Secondly, for any chopper slit, the angle formed with the pre-slit is constant. Therefore, the overlapping area formed during intersection and the shape and size of the flying spot are constant, and no excessive image correction is required, which is beneficial to improving the final image quality. At the same time, the backscatter imaging system uses multiple modules to achieve intelligent control of the backscatter imaging device, which is conducive to the rapid inspection of scanned images and improves the detection efficiency and accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation imaging inspection, and particularly to a backscatter imaging device and a backscatter detection system. Background Art

[0002] An X-ray inspection system can effectively obtain internal images of a target object to be measured, and can detect whether there are metals and organic contraband hidden in the object to be measured. It has been widely equipped in units such as airports, customs, ports, and public security border defense. Compared with the traditional X-ray transmission imaging technology, the backscatter imaging technology has the advantages that the detector can be placed on the same side as the target object to be measured and the organic matter is highlighted, making the backscatter imaging technology more suitable for detecting drugs, explosives, etc. under large objects and complex inspection environments.

[0003] Among them, there are mainly three backscatter imaging methods: a flying spot / pencil beam scanning imaging scheme; a linear array collimated detector combined with a fan beam scanning imaging scheme; and a planar array collimated detector combined with a cone beam scanning imaging scheme.

[0004] Due to the advantages of simple structure, low detection dose, and fast imaging speed of the flying spot imaging technology. Currently, the backscatter imaging devices applied in the security inspection field all adopt the flying spot / pencil beam scanning scheme. Specifically, a collimating slit is placed in front of the radiation source. First, the cone beam rays or a wider fan beam are collimated into a thin fan beam, and then a chopping flywheel is arranged in front of the collimator. A plurality of slits are arranged at equal angles on the chopping flywheel, and the flywheel is driven by a motor. During the rotation of the flywheel, the slits on the flywheel intersect with the slits of the pre-collimator of the radiation source to form periodic flying spots from top to bottom or from left to right to scan the object.

[0005] The existing technical solutions such as the above can better achieve backscatter imaging, but this method of uniformly arranging slits at equal angles on the chopping flywheel and forming flying spots by the intersection of the chopping slits and the collimating slits also has many defects, such as Figure 1 As shown in the figure, first, the motor always maintains an equal angular velocity during the stable rotation process. However, due to the certain length of the slits, there is a relatively large difference in linear velocity at the position near the circumference and the position near the center of the chopping slits. This difference will cause differences in the exposure time of each detection point during detection, thereby introducing differences in signal exposure intensity. In addition, an overlapping area will be generated during the intersection of the chopping slits and the collimating slits to form flying spots, and the shape of the flying spots will also change. For example, a rectangle or a square is formed during orthogonal intersection, and a parallelogram or a rhombus is formed during other intersection processes. Moreover, this parallelogram or rhombus is large at both ends of the slit and small in the middle, which is reflected in the deformation of the shape of the exposure point source and the exposure area during the exposure of the object to be detected, or local repeated exposure or exposure loss, and correction needs to be carried out during the reconstruction process. The above affects the image resolution quality of backscatter imaging. Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a backscatter imaging device and a backscatter imaging system, which are used to solve the problems of unstable exposure time and easy differences in the shape of flying spots in the prior art.

[0007] To achieve the above purpose and other related purposes, the present invention provides a backscatter imaging device, which includes a radiation source, a pre-collimator, a chopper collimator, and a backscatter detector arranged in sequence. The chopper collimator is arranged with multiple chopper slits along the direction of the first side, and the projections of the multiple chopper slits on the first side are connected end to end. The chopper collimator is connected with a driving component, and the driving component is used to drive the chopper collimator to reciprocate along the direction of the first side.

[0008] Further, the backscatter imaging device further includes a conveying mechanism located on the side of the backscatter detector away from the radiation source.

[0009] Further, the multiple chopper slits are divided into several slit groups, and the chopper slits belonging to the same slit group are parallel to each other.

[0010] Further, when the chopper slit overlaps with the pre-slit, the chopper collimator operates in the uniform transmission area.

[0011] Further, the materials of the pre-collimator and the chopper collimator are lead or tungsten, and the widths of the chopper slit and the pre-slit are 0.1 - 0.5 mm.

[0012] Further, the pre-collimator has a pre-slit, and the projection of the chopper slit on the pre-collimator forms an angle A with the pre-slit, where 15° ≤ A ≤ 165°.

[0013] The present invention also provides a backscatter detection system, which includes the backscatter imaging device. The backscatter detection system further includes:

[0014] A central control controller, which is respectively communicatively connected with a radiation source controller, the backscatter detector, and the driving component;

[0015] A driving module, which is communicatively connected with the central control controller;

[0016] An imaging control module, which is communicatively connected with the driving module.

[0017] Further, the imaging control module is further connected with a display module.

[0018] Further, the radiation source controller is communicatively connected with the radiation source.

[0019] Further, the backscattering detector includes an ADC module and more than two sub-detectors, and the ADC module is communicatively connected to the sub-detectors and the central control controller respectively.

[0020] As described above, the backscattering imaging device and the backscattering imaging system of the present invention have the following beneficial effects: The chopper collimator of the backscattering imaging device includes a plurality of chopper slits arranged along the first side direction. The chopper slits perform a reciprocating linear motion and overlap with the pre-slit to form a flying point. Compared with the chopper slits that perform circular motion in the prior art, it has many advantages. The speeds of the linear-moving chopper slits are the same everywhere. Therefore, the exposure time is constant during the intersection with the pre-slit, and there will be no difference in the intensity of exposure. Secondly, for any chopper slit, the angle formed with the pre-slit is constant. Therefore, the overlapping area formed during the intersection and the shape and size of the flying point are constant, and there is no need for excessive image correction, which is beneficial to improving the final image quality. Further optimizing the detection effect on the object to be measured and improving the detection accuracy. At the same time, the backscattering imaging system uses multiple modules to achieve intelligent control of the backscattering imaging device, which is conducive to the rapid inspection of scanned images and improves the detection efficiency and accuracy. Description of the Drawings

[0021] Figure 1 Schematic diagram showing the overlap of the chopper slit and the collimating slit of the chopper disk in the prior art.

[0022] Figure 2 Schematic diagram showing the structure of the backscattering imaging device in the present invention.

[0023] Figure 3(a) shows a schematic diagram of the structure of the chopper collimator including one slit group in the present invention.

[0024] Figure 3(b) shows a schematic diagram of the structure of the chopper collimator including two slit groups in the present invention.

[0025] Figure 4 Schematic diagram showing the chopper collimator working in the uniform transmission area in the present invention.

[0026] Figure 5 Schematic diagram showing the module connection of the backscattering imaging system in the present invention.

[0027] Description of Component Labels

[0028] 101 - Radiation source; 102 - Pre - collimator; 103 - Chopper collimator; 104 - Driving component; 105 - Backscatter detector; 106 - Transmission mechanism; 107 - Object to be measured; 130 - First side; 121 - Pre - slit; 131 - First slit; 132 - Second slit; 133 - Third slit; 201 - Central control controller; 202 - Driving module; 203 - Imaging control module; 111 - Radiation source controller; 204 - Display module; 151 - ADC module; 152 - Sub - detector. Detailed implementation manners

[0029] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] When detailing the embodiments of the present invention, for ease of explanation, the cross - sectional views showing the device structure will be enlarged locally in a non - general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention here. In addition, in actual production, three - dimensional spatial dimensions including length, width, and depth should be included.

[0031] For the convenience of description, spatial relationship terms such as "below", "beneath", "lower than", "under", "above", "on" may be used herein to describe the relationship between one element or feature shown in the drawings and other elements or features. It will be understood that these spatial relationship terms are intended to encompass other directions of the device in use or operation, in addition to the directions depicted in the drawings. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers. As used herein, "between... and..." means including the endpoint values.

[0032] In the context of the present application, the structure in which the first feature is "above" the second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0033] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0034] This embodiment provides a backscattering imaging device, as Figure 2-4 shown. The backscattering imaging device includes a ray source 101, a pre - collimator 102, a chopper collimator 103, and a backscattering detector 105 arranged in sequence. The chopper collimator 103 is arranged with a plurality of chopper slits along the direction of the first side 130. The projections of the plurality of chopper slits on the first side 130 are connected end to end. The chopper collimator 103 is connected with a driving component 104, and the driving component 104 is used to drive the chopper collimator 103 to reciprocate along the direction of the first side.

[0035] Further, the pre - collimator 102 has a pre - slit 121. The projection of the chopper slit on the pre - collimator 102 forms an angle A with the pre - slit 121, where 15° ≤ A ≤ 165°.

[0036] Further, the backscattering imaging device further includes a conveying mechanism 106 located on the side of the backscattering detector 105 away from the ray source 101.

[0037] Specifically, the ray source 101 is used to generate a conical X - ray beam. The conical X - ray beam is restricted to a thin - sheet - shaped fan - shaped X - ray beam after passing through the pre - slit 121 of the pre - collimator 102. When the chopper slit moves along the direction of the first side 130, it will overlap with the pre - slit. The overlapping area allows the fan - shaped X - ray beam to pass through, that is, provides a channel for the X - ray to exit, forming a flying spot (also called a pencil beam). When any chopper slit moves, it will generate a changing overlapping area with the pre - slit 121 from bottom to top or from top to bottom, thereby forming a continuous flying spot and completing the line scan of the object to be measured 107 in the vertical direction. After completing one line scan, the conveying mechanism 106 drives the object to be measured 107 to move a certain distance, and then the next slit overlaps with the pre - slit 121 to perform the next line scan. As the object to be measured 107 moves continuously, the entire surface of the object to be measured 107 is finally scanned. When the flying spot projects onto the surface of the object to be measured 107, it generates Compton backscattering with the electrons in the object to be measured 107. The scattered photons are received by the backscattering detector 105 and converted into voltage signals through photoelectric conversion. The magnitude of the corresponding voltage signal will be used as the image brightness / gray - scale value, and finally the X - ray backscattering image is reconstructed, thereby completing the imaging detection of the object to be measured 107.

[0038] In this embodiment, as Figure 2, the conveying mechanism 106 can adopt a conveyor belt, and the driving component 104 can adopt a high-speed electric cylinder. However, the types of the conveying mechanism 106 and the driving component are not limited thereto. It should be understood that in this embodiment, the conveying mechanism 106 and the driving component 104 can select different operating speeds according to the requirements of the actual application scenario, as long as the generated flying spots can meet the scanning accuracy of the two-dimensional plane of the object to be measured 107. Therefore, the specific operating speeds of the conveying mechanism 106 and the driving component 104 are not limited. In addition, the relative distances between the radiation source 101, the pre-collimator 102, the chopper collimator 103, the backscatter detector 105, and the conveying mechanism 106 are not specifically limited either. In practice, they can be adjusted according to needs, as long as flying spots of appropriate size can be formed on the object to be measured.

[0039] The chopping slit in the present invention makes a reciprocating linear motion along the direction of the first side 130. Compared with the chopping slit that makes a circular motion in the prior art, it has many advantages. The speeds of all parts of the linearly moving chopping slit are the same. Therefore, the exposure time is constant during the intersection with the pre-slit, and there will be no difference in the intensity of exposure. Secondly, for any chopping slit, the angle formed with the pre-slit is constant. Therefore, the overlapping area formed during intersection and the shape and size of the flying spot are constant, and not much image correction is required, which is beneficial to improving the final image quality.

[0040] At the same time, the projections of multiple chopping slits on the first side 130 are connected end to end. The purpose is to limit that multiple chopping slits cannot cross each other, ensuring that only one chopping slit overlaps with the pre-slit 121 at any time, and multiple chopping slits cannot overlap with the pre-slit 121 simultaneously. Otherwise, multiple flying spots will be generated simultaneously, and normal testing cannot be carried out. The included angle A should satisfy the condition 15° ≤ A ≤ 165°, such as 15°, 45°, 60°, etc. If the included angle A is too large, a longer stroke is required to complete the overlap of one chopping slit with the pre-slit, which is time-consuming and affects the testing efficiency. The smaller the included angle A, the shorter the stroke and time required to complete the overlap, and the faster the imaging speed. It should be understood that the included angle A cannot be equal to 0°, that is, the chopping slit and the pre-slit 121 cannot be in a parallel state, otherwise the overlapping area will present a gap state and no flying spot can be generated.

[0041] Furthermore, multiple chopping slits are divided into several slit groups, and the chopping slits belonging to the same slit group are parallel to each other.

[0042] Preferably, multiple chopping slits can form one slit group. As shown in Fig. 3(a), it includes multiple mutually parallel first slits 131. One slit group corresponds to one control mode, and the scanning process and graphic processing are relatively fast and simple. Optionally, multiple chopping slits can form two slit groups. As shown in Fig. 3(b), it includes multiple mutually parallel second slits 132 and multiple mutually parallel third slits 133. A fixed angle is formed between the second slits 132 and the third slits 133, and they are connected end to end. Of course, the number of slit groups is not limited to two, and can also be three, four, etc., as long as the projections of multiple chopping slits on the first side 130 are connected end to end. In this embodiment, the number and setting method of the chopping slits and the slit groups can be selected according to different actual application scenarios, and no excessive limitation is made here.

[0043] Further, when the chopping slit overlaps with the pre - collimating slit, the chopping collimator 103 operates in the uniform transmission area.

[0044] Specifically, as Figure 4 shown, the driving component 104 drives the chopping collimator 103 to perform reciprocating linear motion, and there must be acceleration and deceleration processes, that is, the variable - speed area. If the chopping slit overlaps with the collimating slit in the variable - speed area, the exposure time, shape, etc. of the flying spot cannot be kept consistent, and finally artifacts and distortions will appear in the image. Therefore, the working range of the chopping collimator 103 is limited to the uniform transmission area to keep the flying spot stable and consistent.

[0045] Further, both the pre - collimator 102 and the chopping collimator 103 are made of heavy - metal materials. Preferably, they can be lead or tungsten, which can effectively shield X - rays at a relatively low thickness. The widths of the chopping slit and the pre - collimating slit are 0.1 - 0.5 mm, and the lengths are slightly shorter than the projection length of the X - ray beam emitted by the radiation source 101 on the pre - collimator 102. The position of the pre - collimating slit 121 should be adjustable. During actual adjustment, it should be ensured that the focus of the X - ray beam emitted by the radiation source 101 is located on the central axis of the pre - collimating slit 121 to ensure that X - rays can pass through the pre - collimating slit 121 smoothly. It should be understood that the back - scatter detector 105 also has a slit to enable X - rays to pass through smoothly, and the detection surface of the back - scatter detector 105 should be set on the side close to the object to be measured 107.

[0046] This embodiment also provides a back - scatter detection system. As Figure 5 shown, the back - scatter detection system includes the back - scatter imaging device, and the back - scatter detection system further includes:

[0047] The central control controller 201 is respectively communicatively connected to the ray source controller 111, the backscatter detector 105, and the drive component 104;

[0048] A drive module 202, communicatively connected to the central control controller 201;

[0049] An imaging control module 203, communicatively connected to the drive module 202;

[0050] Further, the ray source controller 111 is communicatively connected to the ray source 101 and is used to control the ray source 101 to generate an X-ray beam. The ray source controller 111 can control the ray source 101 to adjust parameters such as the intensity and emission angle of the X-ray beam.

[0051] Further, the imaging control module 203 is further connected to a display module 204, and the display module 204 can be a display.

[0052] Further, the backscatter detector 105 includes an ADC module 151 and two or more sub-detectors 152. The ADC module 151 is respectively communicatively connected to the sub-detectors 152 and the central control controller 201. When there are two or more sub-detectors 152, the slit between adjacent sub-detectors 152 can be conveniently arranged on the same axis as the pre-slit 121 and the ray source 101. Among them, the ADC module 151 is a common analog-to-digital converter or analog / digital converter, that is, Analog-to-Digital Converter (ADC). An ADC is a device that can convert an analog signal of a continuous variable into a discrete digital signal, such as temperature, pressure, sound, or image, etc., into a digital signal that is easier to store, process, or transmit. As Figure 5 As shown, in this embodiment, the X-ray beam generated by the ray source 101 passes through the pre-collimator 102 and the chopper collimator 103 in sequence to form a flying spot, and then passes through the slit of the backscatter detector 105 to reach the surface of the object to be measured 107. When the flying spot projects onto the surface of the object to be measured 107, Compton backscattering occurs with the electrons in the object to be measured 107. After the sub-detector 152 receives the scattered photons on the surface of the object to be measured 107, a voltage signal is generated. The voltage signal is processed by the ADC module 151 and converted into a digital signal, and then transmitted to the imaging control module 203 via the central control controller 201 and the drive module 202. After image processing, an image is generated and displayed by the display module 204.

[0053] Specifically, the imaging control module 203 may include control software for controlling the operation of the entire backscatter detection system; the drive module 202 includes an operating system and driver programs for driving the central control controller 201, and the central control controller 201 is used to control the ray source controller 111, the drive component 104, and the ADC module 151, and the display module 204 is used for final image display.

[0054] The backscatter imaging system realizes intelligent control of the ray source 101, the drive component 104, and the backscatter detector 105 through multiple modules, enabling the entire backscatter imaging device to operate in coordination, facilitating the rapid inspection of scanned images, and improving the detection efficiency and accuracy.

[0055] In summary, the present invention provides a backscatter imaging device and a backscatter imaging system. The chopper collimator of the backscatter imaging device includes a plurality of chopper slits arranged along the first side direction. The chopper slits perform reciprocating linear motion and overlap with the pre-slit to form a flying point. Compared with the chopper slits that perform circular motion in the prior art, it has many advantages. The speeds of the linearly moving chopper slits are the same everywhere. Therefore, the exposure time is constant during the intersection with the pre-slit, and there will be no difference in the intensity of exposure. Secondly, for any chopper slit, the angle formed with the pre-slit is constant. Therefore, the overlapping area formed during intersection and the shape and size of the flying point are constant, and no excessive image correction is required, which is beneficial to improving the final image quality. Further optimizing the detection effect on the object to be measured and improving the detection accuracy. At the same time, the backscatter imaging system uses multiple modules to achieve intelligent control of the backscatter imaging device, facilitating the rapid inspection of scanned images and improving the detection efficiency and accuracy.

[0056] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A backscattering imaging device, characterized in that, the backscattering imaging device comprises a radiation source, a pre - collimator, a chopper collimator, and a backscattering detector arranged in sequence. The pre - collimator has a pre - slit. The chopper collimator is arranged with multiple chopper slits along the linear direction of the first side. The multiple chopper slits are divided into several slit groups, and the chopper slits belonging to the same slit group are parallel to each other. The projections of the multiple chopper slits on the first side are connected end to end, and there can be no intersection among the multiple chopper slits, ensuring that at any time, only one chopper slit overlaps with the pre - slit. The projection of the chopper slit on the pre - collimator forms an angle A with the pre - slit, where 15° ≤ A ≤ 165°; the chopper collimator is connected with a driving component, and the driving component is used to drive the chopper collimator to move reciprocally along the direction of the first side. When any chopper slit moves, it will generate an overlapping area that changes from bottom to top or from top to bottom with the pre - slit, thereby forming continuous flying points. When the chopper slit overlaps with the pre - slit, the chopper collimator operates in a uniform transmission area.

2. The backscattering imaging device according to claim 1, characterized in that, the backscattering imaging device further comprises a conveying mechanism located on the side of the backscattering detector away from the radiation source.

3. The backscattering imaging device according to claim 1, characterized in that, the materials of the pre - collimator and the chopper collimator are lead or tungsten, and the widths of the chopper slit and the pre - slit are 0.1 - 0.5 mm.

4. A backscattering detection system, characterized in that, the backscattering detection system comprises the backscattering imaging device according to any one of claims 1 - 3, and the backscattering detection system further comprises: a central control controller, which is respectively communicatively connected with a radiation source controller, the backscattering detector, and the driving component; a driving module, communicatively connected with the central control controller; an imaging control module, communicatively connected with the driving module.

5. The backscattering detection system according to claim 4, characterized in that: the imaging control module is further connected with a display module.

6. The backscattering detection system according to claim 4, characterized in that: the radiation source controller is communicatively connected with the radiation source.

7. The backscattering detection system according to claim 4, characterized in that: the backscattering detector comprises an ADC module and more than 2 sub - detectors, and the ADC module is respectively communicatively connected with the sub - detectors and the central control controller.

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