Ray inspection system and scattering correction method

Abstract

The invention relates to a ray inspection system and a scattering correction method. The ray inspection system comprises: a ray source (1) configured to generate a ray beam (10); at least part of the first detector array (2) is located in the coverage range of the ray beam (10); the second detector array (3) and the first detector array (2) are located on the same side of an inspection object (4) of the ray inspection system, the second detector array (3) is located outside the coverage range of the ray beam (10), and the second detector array (3) is configured to receive scattered signals of the ray beam (10) in the process of penetrating through the inspection object; and the processor is in signal connection with the first detector array and the second detector array, and is configured to convert the scattering signals according to a preset relationship between the scattering signal detection capabilities of the first detector array and the second detector array, and perform scattering correction on the received signals of the first detector array according to the converted scattering signals.

Description

[0001] Divisional Explanation

[0002] This application is a divisional application of the parent application with the application number “202010253098.7”, the application date of April 2, 2020, and the invention name of “Radiographic inspection system and scatter correction method”. TECHNICAL FIELD

[0003] The present disclosure relates to the field of radiographic inspection, and in particular, to a radiographic inspection system and a scatter correction method. BACKGROUND

[0004] In the field of X-ray inspection, scatter is usually the main cause of image quality degradation and false signals. The related art research on scatter correction is mainly for CT type inspection systems. The X-ray energy used by such inspection systems is generally in the level of several hundred keV, and the X-ray is a cone beam. Scatter correction is usually achieved by complex algorithm analysis.

[0005] In other application scenarios, such as container inspection systems used in customs, X-rays with higher energy levels, such as megavolt X-rays, are often used. In order to reduce the influence of scatter, the related art reduces scatter signals by increasing shielding and collimators. SUMMARY

[0006] In one aspect of the present disclosure, a radiographic inspection system is provided, comprising:

[0007] a radiation source configured to generate a radiation beam;

[0008] a first detector array located at least partially within a coverage range of the radiation beam;

[0009] a second detector array located on the same side of an inspection object of the radiographic inspection system as the first detector array and outside the coverage range of the radiation beam, the second detector array being configured to receive scatter signals of the radiation beam in the process of penetrating the inspection object; and

[0010] a processor in signal connection with the first detector array and the second detector array, configured to convert the scatter signals according to a preset relationship between the scatter signal detection capabilities of the first detector array and the second detector array, and to perform scatter correction on the received signals of the first detector array according to the converted scatter signals.

[0011] In some embodiments, the processor is configured to calibrate the preset relationship between the scatter signal detection capabilities of the first detector array and the second detector array.

[0012] In some embodiments, the preset relationship is expressed as:

[0013] RSSIC=a*RSSIO;

[0014] wherein RSSIO is the signal strength of the scattered signal detected by the second detector array, RSSIC is the signal strength of the converted scattered signal, and a is a proportional coefficient.

[0015] In some embodiments, the proportional coefficient a is greater than 0 and less than 1. In some embodiments, the first detector array comprises at least one group of first detector modules, each group of first detector modules comprising a plurality of first detector modules arranged along a first direction, and the second detector array comprises at least one group of second detector modules, each group of second detector modules comprising a plurality of second detector modules arranged along the first direction; the first direction is parallel to the beam plane of the beam flow.

[0016] In some embodiments, the number of first detector modules in each group of first detector modules is the same as the number of second detector modules in each group of second detector modules, and each first detector module in each group of first detector modules corresponds to each second detector module in each group of second detector modules one-to-one, and has the same position as the corresponding second detector module in the first direction.

[0017] In some embodiments, the second detector array comprises one group of second detector modules located on one side of the first detector array in a second direction, or the second detector array comprises two groups of second detector modules respectively located on both sides of the first detector array in the second direction; wherein the second direction is perpendicular to the beam plane of the beam flow.

[0018] In some embodiments, the first detector modules included in the first detector array and the second detector modules included in the second detector array are all the same in specification.

[0019] In some embodiments, the first detector modules included in the first detector array and the second detector modules included in the second detector array are different in at least one of specification, number, and arrangement position.

[0020] In some embodiments, the distance between the first detector array and the second detector array in the second direction is greater than the minimum pixel size in the sensitive area of the first detector array and the sensitive area of the second detector array, and the second direction is perpendicular to the beam plane of the beam flow.

[0021] In some embodiments, the radiation beam generated by the radiation source is an X-ray beam, and the electron beam energy of the X-ray beam is greater than or equal to 1.0 MeV, and / or the width of the radiation beam generated by the radiation source is no more than 100 mm.

[0022] According to one aspect of the present disclosure, a scatter correction method based on the aforementioned radiation inspection system is provided, comprising:

[0023] receiving a detection signal detected by the first detector array and receiving a scatter signal detected by the second detector array;

[0024] performing scatter correction on the detection signal according to the scatter signal to obtain a corrected detection signal as a penetration signal when the radiation beam passes through the object under inspection.

[0025] In some embodiments, the first detector array includes first detector modules that are identical to the second detector array in terms of specifications, number, and arrangement of the second detector modules, and the step of scatter correction comprises:

[0026] subtracting the scatter signal from the detection signal to obtain the penetration signal.

[0027] In some embodiments, the step of scatter correction comprises:

[0028] converting the scatter signal according to a preset relationship between the scatter signal detection capabilities of the first detector array and the second detector array to obtain a converted scatter signal;

[0029] subtracting the converted scatter signal from the detection signal to obtain the penetration signal.

[0030] In some embodiments, further comprising:

[0031] calibrating the preset relationship between the scatter signal detection capabilities of the first detector array and the second detector array.

[0032] In some embodiments, the preset relationship is expressed as:

[0033] RSSI C =a*RSSI O ;

[0034] wherein RSSI O is the signal intensity of the scatter signal detected by the second detector array, RSSI C is the signal intensity of the converted scatter signal, and a is a proportional coefficient.

[0035] In some embodiments, the proportional coefficient a is greater than 0 and less than 1.

[0036] In some embodiments, the first detector array comprises a plurality of first detector modules, at least one of the plurality of first detector modules comprises a plurality of first detection units, the second detector array comprises a plurality of second detector modules, at least one of the plurality of second detector modules comprises a plurality of second detection units;

[0037] In the conversion of the scattered signals, a proportional coefficient corresponding to an edge detection unit in the plurality of second detection units is greater than a proportional coefficient corresponding to a non-edge detection unit in the plurality of second detection units.

[0038] In some embodiments, after the conversion of the scattered signals, further comprising:

[0039] The converted scattered signals are smoothed and de-noised, and the smoothed and de-noised scattered signals are taken as the converted scattered signals.

[0040] Therefore, according to the embodiments of the present disclosure, the first detector array is at least partially arranged in the coverage range of the ray beam, and the second detector array is arranged at the side of the first detector array and outside the coverage range of the ray beam, so as to use the scattered signals detected by the second detector array to perform scattered correction on the detection signals received by the first detector array, remove the scattered signals in the detection signals as much as possible, and thus reduce or eliminate the interference of the scattered signals on the results of the ray examination. BRIEF DESCRIPTION OF DRAWINGS

[0041] The accompanying drawings, which form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0042] The present disclosure can be more clearly understood and appreciated from the following detailed description, taken in conjunction with the following drawings of which:

[0043] Figure 1 is the bremsstrahlung spectrum of an electron accelerator of a megavoltage X-ray examination system;

[0044] Figure 2 is the mass attenuation coefficient diagram of X-rays of different photon energies acting on steel materials;

[0045] Figure 3 is a cross-sectional structural schematic diagram of a top view angle according to some embodiments of the ray examination system of the present disclosure;

[0046] Figure 4 is a cross-sectional structural schematic diagram of a side view angle according to some embodiments of the ray examination system of the present disclosure;

[0047] Figure 5 andFigure 6 are structural diagrams of a first detector module and a second detector module, respectively, in some embodiments of the radiographic system of the present disclosure;

[0048] Figures 7-9 are flow diagrams of some embodiments of the scatter correction method of the present disclosure;

[0049] Figure 10 is a signal intensity diagram of a penetrating signal detected by a portion of the detector elements in the first detector array, a scatter signal detected by a portion of the detector elements in the first detector array, and a sum of the two in some embodiments of the radiographic system of the present disclosure;

[0050] Figure 11 is a signal intensity diagram of a scatter signal detected by a portion of the detector elements in the first detector array and a scatter signal detected by a portion of the detector elements in the second detector array located at different positions in some embodiments of the radiographic system of the present disclosure;

[0051] Figure 12 is a signal intensity diagram of a penetrating signal detected by the first detector array, a scatter signal detected by the second detector array and then converted and smoothed to remove noise, and a penetrating signal obtained by scatter correction of the scatter signal in some embodiments of the radiographic system of the present disclosure;

[0052] Figure 13 (a) and (b) of are a penetrating force image generated by the first detector array without scatter correction and a penetrating force image after scatter correction, respectively, in some embodiments of the radiographic system of the present disclosure.

[0053] It should be understood that the dimensions of the various portions shown in the drawings are chosen for purposes of illustration only, and are not intended to be limiting. Further, like or similar reference numerals are intended to refer to like or similar components. DETAILED DESCRIPTION

[0054] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses, except as described in the Claims. The present disclosure can be implemented in numerous different forms, as will be apparent to one of ordinary skill in the art. The embodiments provided are in the nature of a best mode of the disclosure and are provided to give a full and enabling disclosure as required by the law, and are not intended to limit the scope of the disclosure or application or uses as set forth in the Claims. One skilled in the art will readily recognize from the disclosure herein, that alternative embodiments of the present disclosure can be constructed without departing from the scope of the present disclosure. Accordingly, the purpose of this description is simply to enable the claims, and not to limit the scope of the disclosure.

[0055] The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different parts. The terms "include", "comprise", and similar terms mean that the elements before the term encompass the elements listed after the term, and do not exclude the possibility of also encompassing other elements. "Up", "down", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0056] In the present disclosure, when it is described that a specific device is located between a first device and a second device, there can be an intervening device between the specific device and the first device or the second device, or there can be no intervening device. When it is described that a specific device is connected to another device, the specific device can be directly connected to the other device without an intervening device, or can not be directly connected to the other device with an intervening device.

[0057] All terms used in the present disclosure, including technical terms or scientific terms, have the same meanings as those understood by a person of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted in a manner consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formalized sense, unless otherwise specifically defined herein.

[0058] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0059] Figure 1 is the bremsstrahlung spectrum of the electron accelerator of the megavoltage X-ray inspection system. Figure 2 is the mass attenuation coefficient diagram of X-rays of different photon energies acting on steel materials.

[0060] In Figure 1 and Figure 2 It can be seen that the megavoltage X-ray energy is high, the highest X-ray photon energy that the electron accelerator can achieve is 6 MeV, and the average X-ray photon energy is 1.5 MeV. When the X-rays emitted by the electron accelerator of the megavoltage X-ray inspection system act on steel materials, the main effect of X-ray photons with an energy of 0.9 MeV or more (especially 1 MeV or more) on steel materials is mainly Compton effect, stronger than photoelectric effect and electron pair effect, so the scattering signal is more significant.

[0061] Due to the high energy of the megavolt X-ray, multiple scattering can be formed when it acts on the object, making the scattering interference more serious. For the composition and shape of the object, which is very unstable, for example, the object may be heavy metal or organic material, and there may be multiple shapes, which will make the correction of the scattering algorithm difficult.

[0062] In addition, the intensity of the scattering is related to the beam width of the X-ray, the larger the beam width, the greater the scattering interference, and the ideal beam width should be basically equal to the corresponding pixel size. However, for the megavolt X-ray inspection system, it is generally used for inspecting objects with a size of several meters such as containers and vehicles, and the distance between the ray source and the detector is generally several meters to more than ten meters. Therefore, in actual use, it is difficult to realize high-precision collimation to accurately constrain the beam width, resulting in that the beam width at the detector position is generally larger than the pixel size. This further increases the scattering interference. For the megavolt X-ray inspection system, it is also difficult to completely avoid the scattering influence by increasing the shielding and collimator.

[0063] Therefore, the embodiments of the present disclosure provide a ray inspection system and a scattering correction method, which can minimize or eliminate the influence of the scattering signal on the inspection result.

[0064] As shown in Figure 3 , it is a cross-sectional structure diagram of the top view angle according to some embodiments of the ray inspection system of the present disclosure. Referring to Figure 3 and Figures 4-6 , in some embodiments, the ray inspection system comprises a ray source 1, a first detector array 2, a second detector array 3 and a processor 5. The ray source 1 is configured to generate a ray beam 10. In some embodiments, the ray source 1 can be an X-ray source, and the ray beam 10 generated by the ray source 1 is an X-ray beam. The electron beam energy of the X-ray beam can be greater than or equal to 1.0 MeV, that is, the ray source 1 is a megavolt ray source. In other embodiments, the ray source 1 can also be other ray sources, such as gamma rays. Alternatively, the electron beam energy of the X-ray beam generated by the X-ray source is lower than 1.0 MeV.

[0065] In Figure 3 and Figure 4 , the ray source 1 can include an electron accelerator 11 and a collimator 12. The ray beam 10 is emitted from the target point T of the electron accelerator 11 and passes through the collimator 12 to form a ray beam area with a certain width and in the form of a fan.

[0066] Referring to Figure 3 , the first detector array 2 is at least partially located in the coverage range of the ray beam 10. In Figure 4In some embodiments, the first detector array 2 comprises at least one set of first detector modules 20, each set of first detector modules 20 comprising a plurality of first detector modules 20 arranged along a first direction x. In some embodiments, the width of the ray beam 10 generated by the ray source 1 is not more than 100 mm, for example 30 mm. For a larger size of the object under examination, the ray beam region formed by the ray beam 10 can be approximated as the beam plane of the ray beam 10, and the first direction x is parallel to the beam plane of the ray beam 10.

[0067] With reference to Figure 3 and Figure 4 In some embodiments, the first direction x is parallel to the beam plane of the ray beam 10, the second direction y is perpendicular to the beam plane of the ray beam 10, and the third direction z is perpendicular to both the first direction x and the second direction y.

[0068] In a set of first detector modules 20, the plurality of first detector modules 20 can be arranged at different angles of yaw, respectively, to adapt to the incident angle of the ray beam 10. In some embodiments, the plurality of first detector modules 20 can have the same or different spacing. With reference to Figure 4 , the first direction x can be perpendicular to the mounting surface of the ray inspection system, and in other embodiments, the first direction x can be at an oblique angle to the mounting surface of the ray inspection system. In some embodiments, the first detector array can comprise more than two sets of first detector modules, and the first direction x along which the plurality of first detector modules in each set of first detector modules are arranged can be the same or different, but all parallel to the beam plane of the ray beam 10.

[0069] The first detector module 20 can comprise a plurality of detection units (for example 16, 32, 48), and for a set of first detector modules 20, the plurality of detection units in each first detector module 20 can be numbered sequentially, and the detection signals received by the detection units of different numbers correspond to different positions of the object under examination. In addition, the first detector module 20 comprises data acquisition circuits and structural members corresponding to the plurality of detection units, so as to form a structural body with a unified external interface with the plurality of detection units. The detection unit can comprise a sensitive body and a data reading electronic circuit.

[0070] In Figure 3 and Figure 4 , the ray beam 10 can pass through the object under examination 4 to reach the first detector array 2. Since the first detector array 2 is at least partially located in the coverage range of the ray beam 10, the detection signals received by the first detector array 2 include both the penetrating signals and the scattered signals.

[0071] The penetrating signal herein refers to a signal generated by a sensitive medium in a detection unit from a ray particle or a photon (for example, an X-ray photon) that passes through a detected substance and a non-sensitive medium thereof and does not interact with the non-sensitive medium. The intensity of the penetrating signal reflects the composition information of the detected substance.

[0072] The scattering signal is a signal generated by a detection unit from a scattered particle or a photon (for example, an X-ray photon) generated by interaction (mainly Compton effect) between a ray particle or a photon (for example, an X-ray photon) and a detected substance, air, etc. This signal may cause the detection result to be poor.

[0073] Figure 10 is a schematic diagram of signal intensity of a penetrating signal, a scattering signal, and a sum of the two detected by part of the detection units in the first detector array in some embodiments of the X-ray inspection system. The diagram is calculated based on a Monte Carlo simulation of a 300 mm penetrating force, and the test method of the penetrating force is referred to Section 8.1 of the national standard “Radiation Type Cargo and / or Vehicle Inspection System (GB / T 19211-2015)”.

[0074] Figure 10 The positions corresponding to the detection unit numbers from 278 to 378 are the signals of the penetrating force steel plate. Figure 10 In the above, the scattering signals with the numbers from 278 to 378 can account for 2 / 3 of the total signal sum, which is higher than the penetrating signal, and thus has a more significant impact on the detection result. Moreover, the upper and lower edges of the steel plate are more severely affected by scattering; at the same time, the adjacent first detector module junctions are also more susceptible to scattering interference.

[0075] In order to reduce or eliminate the influence of the scattering signal, the second detector array 3 can be arranged on the same side of the first detector array 2 with respect to the inspection object 4 of the X-ray inspection system and outside the coverage range of the ray beam 10. The first detector array 2 and the second detector array 3 can be arranged on the same arm support 6 or on different arm supports, respectively.

[0076] Since the second detector array 3 is located outside the coverage range of the ray beam 10, it cannot receive the penetrating signal of the ray beam 10 in the process of penetrating the inspection object 4, but receives the scattering signal of the ray beam 10 in the process of penetrating the inspection object 4.

[0077] Figure 11 is a schematic diagram of signal intensity of a scattering signal detected by part of the detection units in the first detector array and a scattering signal detected by part of the detection units in the second detector array located at different positions in some embodiments of the X-ray inspection system. It has been verified through experiments that, in the above, Figure 11In the diagram, the curve corresponding to 0mm is the signal intensity curve of the scattered signal detected by the detection units numbered 256 to 384 in the first detector array, while the curves corresponding to 30mm and 60mm are the signal intensity curves of the scattered signal detected by the detection units numbered 256 to 384 in the second detector array, which are offset by 30mm and 60mm relative to the first detector array in the second direction y.

[0078] exist Figure 11 In the diagram, the penetrating steel plate corresponds to detection units numbered 278 to 378. It can be observed that the scattered signal intensities at these three locations are not significantly different. As the offset distance of the second detector array relative to the first detector array increases, the scattered signal received by the detection units in the second detector array decreases. Furthermore, considering that scattering generally consists of forward scattering and background scattering formed by multiple scattering, its signal intensity distribution in space generally does not change abruptly, and the scattering intensity decreases smoothly with increasing beam spacing.

[0079] Since there is a correspondence between the scattered signal received by the first detector array and the scattered signal received by the second detector array, the present embodiment uses a processor 5, which is signal-connected to the first detector array 2 and the second detector array 3, to perform the correction of the received signal of the first detector array 2. That is, the scattered signal is converted according to a preset relationship between the scattered signal detection capabilities of the first detector array 2 and the second detector array 3 to obtain the converted scattered signal, and the received signal of the first detector array 2 is corrected for scattering based on the converted scattered signal.

[0080] By using the scattering signal detected by the second detector array to perform scattering correction on the detection signal received by the first detector array, the scattering signal in the detection signal can be removed as much as possible, thereby minimizing or eliminating the interference of the scattering signal on the X-ray inspection results.

[0081] Specifically, the converted scattering signal is subtracted from the detection signal to obtain the penetration signal. Since the influence of the scattering signal is removed, the obtained penetration signal can achieve a more accurate detection result.

[0082] The preset relationship is calibrated by the processor. Before the first detector array 2 and the second detector array 3 detect the object under test 4, the processor determines and calibrates the preset relationship between the detection capabilities of the scattered signals of the first detector array 2 and the second detector array 3 through multiple experiments.

[0083] For example, for a second detector array with detector modules of different specifications or located far from the first detector array, the value of the scattered signal intensity RSSI1 received by each detection unit in the first detector array can be determined through multiple experiments, and the value of the scattered signal intensity RSSI1 received by each detection unit in the second detector array can also be determined. The ratio a = RSSI1 / RSSI2 of the two signal intensities can be determined statistically as a proportionality coefficient, thereby calibrating the expression based on the ratio a.

[0084] During normal detection, the expression RSSI of the preset relationship can be used. C =a*RSSI O Perform the conversion. RSSI O RSSI represents the signal strength of the scattered signal detected by the second detector array 3. C This represents the signal strength of the converted scattered signal.

[0085] The second detector array 3 includes at least one group of second detector modules 30. Each group of second detector modules 30 includes multiple second detector modules 30 arranged along the first direction x, and their arrangement can be referred to Figure 4 The arrangement of multiple first detector modules 20 in the first detector array 2.

[0086] To facilitate the arrangement of the detector array and the calculation of scattering correction, in some embodiments, the number of first detector modules 20 in each group of first detector modules 20 is the same as the number of second detector modules 30 in each group. Each first detector module 20 in each group of first detector modules 20 corresponds one-to-one with each second detector module 30 in each group of second detector modules 30, and their positions in the first direction x are the same. Thus, each first detector module 20 has a corresponding second detector module 30 with a slight offset, and consequently, the scattering signal received by the second detector module 30 is essentially the same as the scattering signal received by the corresponding first detector module 20. In other embodiments, the number of first detector modules 20 in each group of first detector modules 20 differs from the number of second detector modules 30 in each group, or their corresponding positions in the first direction x are different. In such cases, curve fitting can be used to fit the signal curves received by the first detector array and the second detector array respectively before calculation. To prevent over-correction caused by inconsistencies in the detection units and signal fluctuations, in some embodiments, the scaling factor a is greater than 0 and less than 1.

[0087] Considering that the edge detection unit 21 (i.e. the outermost detection unit along the arrangement direction of the multiple detection units) in the first detector module 20 is more significantly affected by the scattered signal than the non-edge detection unit 22, the scaling factor corresponding to the edge detection unit 31 in the multiple second detection units is made greater than the scaling factor corresponding to the non-edge detection unit 32 in the multiple second detection units when converting the scattered signal.

[0088] exist Figure 3 In the first detector array 2, the second detector array 3 includes a set of second detector modules 30 located on one side of the first detector array 2 in the second direction y. In other embodiments, the second detector array 3 includes two sets of second detector modules 30, located on opposite sides of the first detector array 2 in the second direction y. The scattered signals received by the two sets of second detector modules 30 can be averaged before being used in the correction calculation.

[0089] refer to Figure 3 In some embodiments, the distance d (i.e., offset distance) between the first detector array 2 and the second detector array 3 in the second direction y is greater than the minimum pixel size Ps in the sensitive areas of the first detector array 2 and the second detector array 3, for example, 10 mm. This distance d can be determined according to the width of the coverage area of ​​the X-ray beam 10, for example, it can be 2 to 10 times Ps, so as to avoid the coverage of the X-ray beam 10 while minimizing the intensity of the received scattered signal.

[0090] In some embodiments, the first detector module 20 included in the first detector array 2 and the second detector module 30 included in the second detector array 3 are identical in specifications. These specifications may include the number, arrangement, and performance of the detection units within the module. When the first detector module 20 included in the first detector array 2 and the second detector module 30 included in the second detector array 3 are identical in specifications, the scattered signal received by the second detector array 3 can be closer to the scattered signal received by the first detector array 3, thereby facilitating the calculation of scattering correction. For example, the scattered signal received by the second detector array can be directly subtracted from the detection signal received by the first detector array to approximately eliminate the scattered signal received by the first detector array, thereby obtaining the penetration signal.

[0091] In other embodiments, the first detector module 20 included in the first detector array 2 differs from the second detector module 30 included in the second detector array 3 in at least one of the following: specifications, quantity, and arrangement. To minimize the scattering signal in the detected signal during scattering correction, the processor 5 can convert the scattering signal according to a preset relationship between the scattering signal detection capabilities of the first detector array 2 and the second detector array 3 to obtain a converted scattering signal. Then, the converted scattering signal is subtracted from the detected signal to obtain the transmitted signal.

[0092] The preset relationship here can be calibrated by the processor. Before the first detector array 2 and the second detector array 3 detect the object 4 under test, the processor can determine and calibrate the preset relationship between the scattered signal detection capabilities of the first detector array 2 and the second detector array 3 through multiple experiments. For example, for the second detector array with detector modules of different specifications or far away from the first detector array, the value of the scattered signal intensity RSSI1 received by each detection unit in the first detector array can be determined through multiple experiments, and the value of the scattered signal intensity RSSI1 received by each detection unit in the second detector array can also be determined. By statistics, the ratio a = RSSI1 / RSSI2 of the two signal intensities is determined as a proportionality coefficient, thereby calibrating the expression based on the ratio a.

[0093] During normal detection, the expression RSSI of the preset relationship can be used. C =a*RSSI O Perform the conversion. RSSI O RSSI represents the signal strength of the scattered signal detected by the second detector array 3. C This represents the signal strength of the converted scattered signal.

[0094] Based on the above embodiments of the X-ray inspection system disclosed herein, this disclosure provides a corresponding scattering correction method. Figures 7-9 These are schematic flowcharts illustrating some embodiments of the scattering correction method disclosed herein. (Reference) Figure 7 In some embodiments, the scattering correction method includes steps 100-200. In step 100, a detection signal detected by a first detector array 2 is received, and a scattering signal detected by a second detector array 3 is received. In step 200, the detection signal is scattered and corrected based on the scattering signal to obtain a corrected detection signal as the penetration signal when the X-ray beam 10 passes through the object under inspection.

[0095] In this embodiment, both steps 100 and 200 are executed by a processor 5 that is signal-connected to the first detector array 2 and the second detector array 3. After the detection signal is corrected, the resulting transmitted signal, having removed the influence of the scattered signal, can obtain a more accurate detection result.

[0096] When the first detector module 20 in the first detector array 2 and the second detector module 30 in the second detector array 3 are identical in specifications, quantity, and arrangement, the scattering correction step in step 200 may include subtracting the scattered signal from the detected signal to obtain the transmitted signal. Since the first detector module 20 and the second detector module 30 are located close to each other and have the same performance, the received scattered signals are also very similar. Therefore, the transmitted signal can be approximated by subtracting the scattered signal from the detected signal.

[0097] For cases where the detector modules of the first detector array 2 and the second detector array 3 have different specifications, quantities, or arrangement positions, or considering the influence of the offset of the second detector array 3 relative to the first detector array 2 on the scattered signal, in other embodiments, reference is made to... Figure 8 The scattering correction step in step 200 may include steps 210 and 230. In step 210, the scattering signal is converted according to a preset relationship between the scattering signal detection capabilities of the first detector array 2 and the second detector array 3 to obtain a converted scattering signal. In step 230, the converted scattering signal is subtracted from the detection signal to obtain the penetration signal.

[0098] To determine the aforementioned preset relationship, in some embodiments, the scattering correction method further includes calibrating a preset relationship between the scattering signal detection capabilities of the first detector array 2 and the second detector array 3. The expression for this preset relationship can be: RSSI C =a*RSSI O Among them, RSSI O RSSI represents the signal strength of the scattered signal detected by the second detector array 3. C The signal strength of the converted scattered signal is represented by 'a', and the scaling factor is 'a'. To prevent overcorrection caused by inconsistencies among the various detection units and signal fluctuations, in some embodiments, the scaling factor 'a' is greater than 0 and less than 1.

[0099] refer to Figure 5 and Figure 6The first detector module 20 may include multiple first detector units, and the second detector module 30 may include multiple second detector units. Considering that the edge detector unit 21 (i.e., the outermost detector unit along the arrangement direction of the multiple detector units) in the first detector module 20 is more significantly affected by the scattered signal than the non-edge detector unit 22, when converting the scattered signal, the scaling factor corresponding to the edge detector unit 31 in the multiple second detector units is made greater than the scaling factor corresponding to the non-edge detector unit 32 in the multiple second detector units.

[0100] refer to Figure 9 To reduce the fluctuations (i.e., scattering noise) in the scattering signal of one or more detector elements in the second detector array, in some embodiments, [the following can be implemented / implemented]: Figure 8 Based on the above, step 220 is added, that is, after step 210, the converted scattering signal is smoothed and denoised, and the smoothed and denoised scattering signal is used as the converted scattering signal. Then, in step 230, the smoothed and denoised scattering signal is used as the converted scattering signal and removed from the detection signal.

[0101] Figure 12 This is a schematic diagram of the signal intensity of the detection signal received by the first detector array, the scattering signal detected by the second detector array and converted and smoothed for noise reduction, and the penetration signal obtained after scattering correction of the scattering signal in some embodiments of the X-ray inspection system disclosed herein.

[0102] exist Figure 12 The diagram shows the signal intensity curves of the detected signal from the first detector array (as the main detector array) and the signal intensity curves of the scattered signal from the second detector array (as the scattering detector array). During the scattering correction process, the signal intensity of the scattered signal is multiplied by a scaling factor of 0.9, and the result is then smoothed. Finally, the signal intensity of the detected signal is subtracted from the smoothed result to obtain the corrected detected signal from the first detector array.

[0103] The scattering correction based on the embodiments of the X-ray inspection system disclosed herein Figure 13 (a) and (b) show the penetration image generated by the first detector array without scattering correction and the penetration image after scattering correction, respectively, for comparison. Figure 13 As can be seen in (a), the image is affected by scattering interference, with the upper and lower edges of the steel plate being brighter. Meanwhile, the image of the lead block on the back side of the steel plate is incomplete. Figure 13 After scattering correction, the image of (b) shows a more uniform brightness of the steel plate and a more complete image of the lead block.

[0104] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0105] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A radiographic inspection system, characterized in that, include: The X-ray source (1) is configured to generate a X-ray beam (10); The first detector array (2) is at least partially located within the coverage area of ​​the X-ray beam (10); The second detector array (3) is located on the same side of the object to be inspected (4) of the X-ray inspection system as the first detector array (2), and outside the coverage area of ​​the X-ray beam (10). The second detector array (3) is configured to receive the scattered signal of the X-ray beam (10) as it passes through the object to be inspected (4). and The processor (5) is signal-connected to the first detector array (2) and the second detector array (3) and is configured to convert the scattering signal according to a preset relationship between the scattering signal detection capabilities of the first detector array (2) and the second detector array (3), and to perform scattering correction on the received signal of the first detector array (2) according to the converted scattering signal.

2. The X-ray inspection system according to claim 1, characterized in that, The processor (5) is configured to calibrate a preset relationship between the scattering signal detection capabilities of the first detector array (2) and the second detector array (3).

3. The X-ray inspection system according to claim 1, characterized in that, The expression for the preset relationship is: RSSIC = a * RSSIO; Where RSSIO is the signal strength of the scattered signal detected by the second detector array (3), RSSIC is the signal strength of the converted scattered signal, and a is the scaling factor.

4. The X-ray inspection system according to claim 3, characterized in that, The proportionality coefficient a is greater than 0 and less than 1.

5. The X-ray inspection system according to any one of claims 1 to 4, characterized in that, The first detector array (2) includes at least one set of first detector modules (20), each set of first detector modules (20) includes a plurality of first detector modules (20) arranged along a first direction (x), and the second detector array (3) includes at least one set of second detector modules (30), each set of second detector modules (30) includes a plurality of second detector modules (30) arranged along a first direction (x); the first direction (x) is parallel to the beam plane of the X-ray beam (10).

6. The X-ray inspection system according to claim 5, characterized in that, The number of first detector modules (20) in each group of first detector modules (20) is the same as the number of second detector modules (30) in each group, and each first detector module (20) in each group of first detector modules (20) corresponds one-to-one with each second detector module (30) in each group of second detector modules (30), and the position of the corresponding second detector module (30) in the first direction (x) is the same.

7. The X-ray inspection system according to claim 5, characterized in that, The second detector array (3) includes a set of second detector modules (30) located on one side of the first detector array (2) in the second direction (y); or the second detector array (3) includes two sets of second detector modules (30) located on both sides of the first detector array (2) in the second direction (y); wherein the second direction (y) is perpendicular to the beam plane of the X-ray beam (10).

8. The X-ray inspection system according to claim 5, characterized in that, The first detector module (20) included in the first detector array (2) and the second detector module (30) included in the second detector array (3) are identical in specifications.

9. The X-ray inspection system according to claim 5, characterized in that, The first detector module (20) included in the first detector array (2) differs from the second detector module (30) included in the second detector array (3) in at least one of the following: specifications, quantity and arrangement.

10. The X-ray inspection system according to any one of claims 1 to 4, characterized in that, The distance (d) between the first detector array (2) and the second detector array (3) in the second direction (y) is greater than the minimum pixel size in the sensitive area of ​​the first detector array (2) and the sensitive area of ​​the second detector array (3), and the second direction (y) is perpendicular to the beam plane of the ray beam (10).

11. The X-ray inspection system according to any one of claims 1 to 4, characterized in that, The X-ray beam (10) generated by the X-ray source (1) is an X-ray beam, and the electron beam energy of the X-ray beam is greater than or equal to 1.0 MeV, and / or the width of the X-ray beam (10) generated by the X-ray source (1) does not exceed 100 mm.

12. A scattering correction method based on the X-ray inspection system according to any one of claims 1 to 11, characterized in that, include: Receive the detection signal detected by the first detector array (2) and the scattering signal detected by the second detector array (3); The detection signal is scattered and corrected according to the scattering signal to obtain the corrected detection signal as the penetration signal when the X-ray beam (10) passes through the object under inspection.

13. The scattering correction method according to claim 12, characterized in that, The first detector array (2) includes a first detector module (20) which is identical in specifications, quantity, and arrangement to the second detector module (30) included in the second detector array (3). The scattering correction steps include: The scattering signal is subtracted from the detection signal to obtain the penetration signal.

14. The scattering correction method according to claim 12, characterized in that, The steps of scattering correction include: The scattered signal is converted according to a preset relationship between the scattered signal detection capabilities of the first detector array (2) and the second detector array (3) to obtain the converted scattered signal; The converted scattering signal is subtracted from the detection signal to obtain the penetration signal.

15. The scattering correction method according to claim 14, characterized in that, Also includes: A preset relationship is calibrated between the scattering signal detection capabilities of the first detector array (2) and the second detector array (3).

16. The scattering correction method according to claim 14, characterized in that, The expression for the preset relationship is: CISO C =a*RSSI O ; Among them, RSSI O RSSI is the signal strength of the scattered signal detected by the second detector array (3). C denoted as the signal strength of the converted scattered signal, and 'a' as the scaling factor.

17. The scattering correction method according to claim 16, characterized in that, The proportionality coefficient a is greater than 0 and less than 1.

18. The scattering correction method according to claim 16, characterized in that, The first detector array (2) includes a plurality of first detector modules (20), at least one of the plurality of first detector modules (20) includes a plurality of first detection units; the second detector array (3) includes a plurality of second detector modules (30), at least one of the plurality of second detector modules (30) includes a plurality of second detection units; When converting the scattered signal, the scaling factor corresponding to the edge detection unit (31) in the plurality of second detection units is greater than the scaling factor corresponding to the non-edge detection unit (32) in the plurality of second detection units.

19. The scattering correction method according to claim 14, characterized in that, After converting the scattered signal, the process also includes: The converted scattering signal is smoothed and denoised, and the smoothed and denoised scattering signal is used as the converted scattering signal.

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