WO2021197075A1

WO2021197075A1 - Radiographic inspection system and scatter correction method

Info

Publication number: WO2021197075A1
Application number: PCT/CN2021/081348
Authority: WO
Inventors: 李树伟; 张清军; 邹湘; 朱维彬; 赵博震; 李祥华; 王钧效
Original assignee: 同方威视技术股份有限公司
Priority date: 2020-04-02
Filing date: 2021-03-17
Publication date: 2021-10-07
Also published as: CN113552640A

Abstract

Provided are a radiographic inspection system and a scatter correction method. The radiographic inspection system comprises: a radiation source (1) configured to generate a radiation beam (10); a first detector array (2) at least partially located within a coverage range of the radiation beam (10); a second detector array (3) located on the same side of an inspected object (4) of the radiographic inspection system as the first detector array (2) and located outside the coverage range of the radiation beam (10), wherein the second detector array (3) is configured to receive a scattered signal of the radiation beam (10) during the process of same being transmitted through the inspected object (4); and a processor (5) that is in signal connection with the first detector array (2) and the second detector array (3) and is configured to perform scatter correction on a received signal of the first detector array (2) on the basis of the scattered signal.

Description

Ray inspection system and scattering correction method

Cross-references to related applications

This application is based on the application with the CN application number 202010253098.7 and the application date on April 2, 2020, and claims its priority. The disclosure of the CN application is hereby incorporated into this application as a whole.

Technical field

The present disclosure relates to the field of radiographic inspection, and in particular to a radiographic inspection system and a scattering correction method.

Background technique

In the field of X-ray inspection, scattering is usually the main cause of image quality degradation and false signals. The research on scatter correction in related technologies is mainly aimed at the research of CT-type inspection systems. The X-ray energy used by this inspection system is generally at the level of several hundred keV, and the X-rays are cone beams. Scattering correction is mostly realized by complex algorithm analysis.

In other application scenarios, such as container inspection systems used in customs, X-rays with higher energy levels, such as mega-volt X-rays, are often used. In order to reduce the influence of scattering, in the related art, shielding and collimator are added to reduce the scattered signal.

Summary of the invention

In one aspect of the present disclosure, a radiographic inspection system is provided, including:

The ray source is configured to generate a beam of rays;

The first detector array is at least partially located within the coverage area of the ray beam;

The second detector array is located on the same side of the inspection object of the radiation inspection system as the first detector array, and is located outside the coverage of the radiation beam, and the second detector array is configured to receive The scatter signal of the beam of rays in the process of passing through the inspection object; and

The processor is signally connected to the first detector array and the second detector array, and is configured to perform scattering correction on the received signal of the first detector array according to the scattering signal.

In some embodiments, the first detector array includes at least one set of first detector modules, and each set of first detector modules includes a plurality of first detector modules arranged along a first direction, and the second detector The detector array includes at least one set of second detector modules, and each set of second detector modules includes a plurality of second detector modules arranged along a first direction; the first direction is parallel to the beam plane of the ray beam .

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, and each first detector module in each group of first detector modules is equal to Each second detector module in each group of second detector modules has a one-to-one correspondence, and the position of the corresponding second detector module in the first direction is the same.

In some embodiments, the second detector array includes a set of second detector modules, and the set of second detector modules is located on one side of the first detector array in the second direction; or the second detector array The detector array includes two sets of second detector modules, the two sets of second detector modules are respectively located on both sides of the first detector array in the second direction; wherein the second direction is in line with the ray beam The beam plane of the stream is vertical.

In some embodiments, the first detector module included in the first detector array and the second detector module included in the second detector array have the same specifications.

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 specifications, numbers, and arrangement positions.

In some embodiments, the distance between the first detector array and the second detector array in the second direction is greater than the sensitive area of the first detector array and the sensitive area of the second detector array The second direction is perpendicular to the beam plane of the beam of rays.

In some embodiments, the processor is configured to calibrate a predetermined relationship between the scattered signal detection capabilities of the first detector array and the second detector array.

In some embodiments, the beam current generated by the ray 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 beam current generated by the ray source has a different width. More than 100mm.

According to one aspect of the present disclosure, there is provided a scatter correction method based on the aforementioned ray inspection system, including:

Receiving the detection signal detected by the first detector array, and receiving the scattering signal detected by the second detector array;

Performing a scatter correction on the detection signal according to the scatter signal to obtain a corrected detection signal as a penetration signal when the ray beam passes through the object to be inspected.

In some embodiments, the specifications, quantity, and arrangement positions of the first detector modules included in the first detector array and the second detector modules included in the second detector array are the same, and the step of scatter correction include:

The scattering signal is subtracted from the detection signal to obtain the penetration signal.

In some embodiments, the step of scatter correction includes:

Converting the scattering signal according to the preset relationship between the scattering signal detection capabilities of the first detector array and the second detector array to obtain a converted scattering signal;

The converted scattering signal is subtracted from the detection signal to obtain the penetration signal.

In some embodiments, it further includes:

Calibrate the preset relationship between the detection capabilities of the scattered signal of the first detector array and the second detector array.

In some embodiments, the expression of the preset relationship is:

RSSI _C =a*RSSI _O ;

Wherein, RSSI _O is the signal intensity of the scattered signal detected by the second detector array, RSSI _C is the signal intensity of the converted scattered signal, and a is a scale factor.

In some embodiments, the scale factor a is greater than 0 and less than 1.

In some embodiments, the first detector array includes a plurality of first detector modules, at least one of the plurality of first detector modules includes a plurality of first detection units, and The second detector array includes a plurality of second detector modules, and at least one second detector module of the plurality of second detector modules includes a plurality of second detection units;

When the scattering signal is converted, the proportional coefficients corresponding to the edge detection units in the plurality of second detection units are larger than the proportional coefficients corresponding to the non-edge detection units in the plurality of second detection units.

In some embodiments, after converting the scattering signal, the method further includes:

Perform smoothing and denoising on the converted scattering signal, and use the smoothed and denoised scattering signal as the converted scattering signal.

Therefore, according to the embodiment of the present disclosure, the first detector array is set at least partially within the coverage of the ray beam, and the second detector is set at the side of the first detector array and outside the coverage of the ray beam. The detector array uses the scattering signal detected by the second detector array to perform scattering correction on the detection signal received by the first detector array, and remove the scattering signal in the detection signal as much as possible, so as to reduce or eliminate the scattering signal as much as possible. Interference with radiographic inspection results.

Description of the drawings

The drawings constituting a part of the specification describe the embodiments of the present disclosure, and together with the specification, serve to explain the principle of the present disclosure.

With reference to the accompanying drawings, the present disclosure can be understood more clearly according to the following detailed description, in which:

Figure 1 is the bremsstrahlung energy spectrum of the electron accelerator of the megavolt X-ray inspection system;

Figure 2 is a graph of mass attenuation coefficients when X-rays with different photon energies act on steel materials;

FIG. 3 is a schematic cross-sectional structure diagram of some embodiments of the radiographic inspection system according to the present disclosure from a top angle;

4 is a schematic diagram of a cross-sectional structure of some embodiments of the radiographic inspection system according to the present disclosure in a side view angle;

5 and 6 are respectively structural schematic diagrams of the first detector module and the second detector module in some embodiments of the radiographic inspection system of the present disclosure;

Figures 7-9 are schematic flowcharts of some embodiments of the scattering correction method of the present disclosure;

10 is a schematic diagram of the penetration signal, the scattered signal and the signal intensity of the sum of the two detected by some of the detection units in the first detector array in some embodiments of the radiographic inspection system of the present disclosure;

11 is a schematic diagram of the signal intensity of the scattered signals detected by some of the detection units in the first detector array and the scattered signals of some of the detection units in the second detector array located at different positions in some embodiments of the radiation inspection system of the present disclosure;

Figure 12 is the detection signal received by the first detector array in some embodiments of the radiation inspection system of the present disclosure, the scatter signal detected by the second detector array and converted and smoothed and denoised, and the scatter signal obtained after the scatter correction of the scatter signal Schematic diagram of the signal strength of the penetrating signal;

Fig. 13 (a) and (b) are respectively the penetration force image generated by the first detector array without scatter correction and the penetration force image after scatter correction in some embodiments of the radiation inspection system of the present disclosure.

It should be understood that the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship. In addition, the same or similar reference numerals indicate the same or similar components.

Detailed ways

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, and in no way serves as any limitation to the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless specifically stated otherwise, the relative arrangement of components and steps, material components, numerical expressions and numerical values set forth in these embodiments should be construed as merely exemplary rather than limiting.

The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. Similar words such as "include" or "include" mean that the element before the word covers the elements listed after the word, and does not exclude the possibility of covering other elements as well. "Up", "Down", "Left", "Right", etc. are only used to indicate the relative position relationship. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

In the present disclosure, when it is described that a specific device is located between the first device and the second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to another device, the specific device may be directly connected to the other device without an intervening device, or may not be directly connected to the other device but with an intervening device.

All terms (including technical terms or scientific terms) used in the present disclosure have the same meaning as understood by those of ordinary skill in the art to which the present disclosure belongs, unless specifically defined otherwise. It should also be understood that terms such as those defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of related technologies, and should not be interpreted in idealized or extremely formalized meanings, unless explicitly stated here. Define like this.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

Figure 1 is the bremsstrahlung energy spectrum of the electron accelerator of the megavolt X-ray inspection system. Figure 2 is a graph of mass attenuation coefficients when X-rays with different photon energies act on steel materials.

It can be seen in Figure 1 and Figure 2 that the megavolt-level X-ray energy is relatively high, and 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 this mega-volt X-ray inspection system act on steel materials, the X-ray photons with energy above 0.9MeV (especially above 1MeV) interact with the steel materials as the Compton effect. Mainly, stronger than the photoelectric effect and the electron pair effect, so the scattered signal is more significant.

Due to the high energy of megavolt X-rays, multiple scattering can be formed when acting on objects, making scattering interference more serious. For the situation where the composition and shape of the inspected object are very unstable, for example, the inspected object may be heavy metals or organic materials, and there may be multiple shapes, which will make the correction of the scattering algorithm difficult.

In addition, the intensity of scattering is related to the width of the X-ray beam. The larger the beam width, the greater the scattering interference. The ideal beam width should be basically equal to the corresponding pixel size. However, for megavolt-level X-ray inspection systems, they are generally used to inspect objects that are several meters in size such as containers and vehicles. The distance between the ray source and the detector is generally from several meters to more than ten meters, so in actual use However, it is difficult to achieve high-precision collimation to accurately constrain the beam width, resulting in the beam width at the detector position generally being larger than the pixel size. This further increases the scattering interference. For megavolt-level X-ray inspection systems, it is difficult to completely avoid the effects of scattering by adding shields and collimators.

In view of this, the embodiments of the present disclosure provide a ray inspection system and a scatter correction method, which can minimize or eliminate the influence of the scatter signal on the inspection result.

As shown in FIG. 3, it is a schematic diagram of the cross-sectional structure of some embodiments of the radiographic inspection system according to the present disclosure from a top view. 3 and 4-6, in some embodiments, the radiation inspection system includes: a radiation source 1, a first detector array 2, a second detector array 3, and a processor 5. The radiation source 1 is configured to generate a beam of radiation 10. In some embodiments, the ray source 1 may be an X-ray source, and the ray beam 10 generated thereby 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-level ray source. In other embodiments, the radiation source 1 may also be other radiation 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.

In FIGS. 3 and 4, the radiation source 1 may 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 fan-shaped ray beam area with a certain width.

Referring to FIG. 3, the first detector array 2 is at least partially located within the coverage area of the ray beam 10. In FIG. 4, the first detector array 2 includes at least one set of first detector modules 20, and each set of first detector modules 20 includes a plurality of first detector modules 20 arranged along a first direction x. In some embodiments, the width of the beam 10 generated by the radiation source 1 does not exceed 100 mm, for example, 30 mm. For a larger-sized object to be inspected, the ray beam area formed by the ray beam 10 can be approximated as the beam plane of the ray beam 10, and the first direction x is the same as the beam plane of the ray beam 10 parallel.

3 and 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.

In a group of first detector modules 20, a plurality of first detector modules 20 may be respectively arranged at different swing angles to adapt to the incident angle of the ray beam 10. In some embodiments, the spacing of the plurality of first detector modules 20 may be the same or different. Referring to FIG. 4, the first direction x may be perpendicular to the installation surface of the radiographic inspection system, and in other embodiments, it may also be at an oblique angle to the installation surface of the radiographic inspection system. In some embodiments, the first detector array may include more than two groups of first detector modules, and the first direction x of the arrangement of the plurality of first detector modules in each group of first detector modules is the same or different, but all It is parallel to the beam plane of the ray beam 10.

The first detector module 20 may include multiple detection units (for example, 16, 32, 48). For a group of first detector modules 20, multiple detection units in each first detector module 20 can be performed in sequence. Number, the detection signals received by the detection units of different numbers correspond to different positions of the inspected object. In addition, the first detector module 20 also includes data acquisition circuits and structural components corresponding to the multiple detection units, so as to form a structure with a unified external interface with the multiple detection units. The detection unit may include a sensitive body and a data reading electronic circuit.

In FIG. 3 and FIG. 4, the ray beam 10 can reach the first detector array 2 after passing through the object 4 to be inspected. Since the first detector array 2 is at least partially located in the coverage area of the ray beam 10, the detection signals received by the first detector array 2 include both penetration signals and scattering signals.

The penetration signal here refers to the signal generated by the sensitive medium in the detection unit of the ray particles or photons (such as X-ray photons) that have passed through the detected substance and other non-sensitive media and have no effect on them. The intensity of the penetration signal reflects the composition information of the test substance.

Scattering signal is the signal generated by the interaction of ray particles or photons (such as X-ray photons) with the test substance, air, etc. (mainly the Compton effect), and the resulting scattered particles or photons reach the detection unit The signal may cause the detection result to deteriorate.

10 is a schematic diagram of the penetration signal, the scattered signal and the signal intensity of the sum of the two detected by some of the detection units in the first detector array in some embodiments of the radiographic inspection system of the present disclosure. The figure is based on Monte Carlo simulation calculation of 300mm penetration force. The penetration force test method refers to section 8.1 of the national standard "Radiation Cargo and/or Vehicle Inspection System (GB/T 19211-2015)".

The position corresponding to the detection unit number from 278 to 378 in Figure 10 is the signal of the penetrating steel plate. In Fig. 10, the scattered signals numbered 278 to 378 can basically account for 2/3 of the total signal, which is higher than the penetration signal, so it has a significant impact on the detection result. In addition, the upper and lower edges of the steel plate are more severely scattered; at the same time, the junction of adjacent first detector modules is more likely to receive scattering interference.

In order to reduce or eliminate the influence of scattered signals, the second detector array 3 can be set to be located on the same side of the inspection object 4 of the radiation inspection system as the first detector array 2 and located on the beam 10 Outside the coverage area. The first detector array 2 and the second detector array 3 can both be arranged on the arm support 6, or can be respectively arranged on different arm supports.

Since the second detector array 3 is located outside the coverage area of the ray beam 10, it cannot receive the penetration signal of the ray beam 10 in the process of passing through the inspection object 4, but it receives the ray beam. 10 Scattered signal in the process of passing through the inspection object 4.

FIG. 11 is a schematic diagram of the signal intensity of the scattered signals detected by some of the detection units in the first detector array and the scattered signals of some of the detection units in the second detector array located at different positions in some embodiments of the radiation inspection system of the present disclosure. After experimental verification, in Figure 11, 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 relative to the first The signal intensity curve of the scattered signals detected by the detector units numbered 256 to 384 in the second detector array whose detector array is offset by 30 mm and 60 mm in the second direction y.

In Figure 11, the penetrating steel plate corresponds to the detection units numbered 278 to 378. It can be seen that the scattered signal strengths of these three positions are not much different. With the deviation of the second detector array relative to the first detector array As the moving distance increases, the scattered signals received by the detection units in the second detector array are reduced. And considering that scattering is generally background scattering formed by forward scattering and multiple scattering, the signal intensity distribution in space generally does not change suddenly, and as the distance from the beam increases, the scattering intensity will decrease smoothly.

Since the scattering signal received by the first detector array has a corresponding relationship with the scattering signal received by the second detector array, the embodiment of the present disclosure uses the processing of signal connection with the first detector array 2 and the second detector array 3 The device 5 performs the correction work of the received signal of the first detector array 2, that is, performs scatter correction on the received signal of the first detector array 2 according to the scattered signal. Scattering correction is performed on the detection signal received by the first detector array through the scattered signal detected by the second detector array, and the scattered signal in the detection signal can be removed as much as possible, so as to minimize or eliminate the scattered signal on the ray inspection result Interference.

The second detector array 3 includes at least one set of second detector modules 30. Each group of second detector modules 30 includes a plurality of second detector modules 30 arranged along the first direction x, the arrangement of which can refer to the plurality of first detector modules 20 in the first detector array 2 in FIG. 4 The arrangement form.

In order to facilitate the arrangement of the detector array and the calculation of the scattering correction, in some embodiments, the number of the first detector modules 20 in each group of the first detector modules 20 is the same as the number of the second detector modules 30 in each group. Each first detector module 20 in each group of first detector modules 20 has a one-to-one correspondence with each second detector module 30 in each group of second detector modules 30, and is in a one-to-one correspondence with the corresponding second detector module 30. The positions in the first direction x are the same. In this way, each first detector module 20 has a second detector module 30 corresponding to its position with a small offset. Correspondingly, the scattering signal that the second detector module 30 can receive can be consistent with the corresponding first detector module. The scattered signals received by the detector module 20 are basically the same.

In other embodiments, the number of first detector modules 20 in each group of first detector modules 20 is different from the number of second detector modules 30 in each group, or the corresponding positions in the first direction x The difference is that in the calculation, the signal curves received by the first detector array and the second detector array can be respectively fitted by curve fitting, and then the calculation can be performed.

In FIG. 3, the second detector array 3 includes a set of second detector modules 30, and the set of second detector modules 30 is 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, and the two sets of second detector modules 30 are respectively located in the first detector array 2 in the second direction y On both sides. The scattered signals received by the two sets of second detector modules 30 can be averaged before participating in the correction operation.

3, in some embodiments, the distance d (ie, the offset distance) between the first detector array 2 and the second detector array 3 in the second direction y is greater than that of the first detector array 2 The minimum pixel size Ps in the sensitive area and the sensitive area of the second detector array 3 is, for example, 10 mm. The distance d can be determined according to the width of the coverage area of the ray beam 10, for example, a value of 2-10 times Ps, so as to avoid the coverage of the ray beam 10 and minimize the received scattering. The strength of the signal.

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 have the same specifications. The specifications here can include the number, arrangement position, performance, etc. of the detection units in 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 have the same specifications, the scattering received by the second detector array 3 The signal can be closer to the scattering signal received by the first detector array 3, thereby facilitating the calculation of the scattering correction. For example, the scattered signal received by the second detector array is directly subtracted from the detection signal received by the first detector array, so as to approximately eliminate the scattered signal received by the first detector array, thereby obtaining the penetration signal.

In other 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 at least One kind is different. In order to eliminate the scattered signal in the detection signal as much as possible during the scatter correction, the processor 5 can compare the scatter signal detection capabilities of the first detector array 2 and the second detector array 3 according to the preset relationship. The scattering signal is converted to obtain the converted scattering signal. Then, the converted scattering signal is subtracted from the detection signal to obtain the penetration signal.

The preset relationship here can be calibrated by the processor. The processor can determine the first detector array 2 and the second detector array through multiple experiments before the first detector array 2 and the second detector array 3 detect the object 4 3. The preset relationship between the detection capabilities of scattered signals and calibrate it. For example, for a second detector array with different specifications of the detector module or a distance from the first detector array, the intensity of the scattered signal received by each detection unit in the first detector array can be determined through multiple experiments. RSSI value of _1, and a second detector array to determine the value of each RSSI detection unit receives _a scattered signal intensity, the signal intensity is determined by counting both the ratio a = RSSI ₁ / RSSI ₂ as the proportional coefficient, whereby Calibrate the expression based on the ratio a.

During normal detection, the conversion can be performed according to the expression RSSI _C =a*RSSI _{O of the preset relationship.} RSSI _O is the signal intensity of the scattered signal detected by the second detector array 3, and RSSI _C is the signal intensity of the converted scattered signal.

Based on the above-mentioned embodiments of the radiation inspection system of the present disclosure, the present disclosure provides a corresponding scatter correction method. Figures 7-9 are schematic flowcharts of some embodiments of the scattering correction method of the present disclosure. Referring to FIG. 7, in some embodiments, the scatter correction method includes step 100-step 200. In step 100, the detection signal detected by the first detector array 2 is received, and the scattering signal detected by the second detector array 3 is received. In step 200, scatter correction is performed on the detection signal according to the scatter signal to obtain the corrected detection signal as the penetration signal when the beam 10 passes through the object to be inspected.

In this embodiment, the execution subjects of step 100 and step 200 are both the processor 5 signally connected to the first detector array 2 and the second detector array 3. After the detection signal is corrected, the obtained penetration signal removes the influence of the scattered signal, so more accurate detection results can be obtained.

In the case where the specifications, quantity, and arrangement positions of the first detector modules 20 included in the first detector array 2 and the second detector modules 30 included in the second detector array 3 are the same, the scatter correction is performed in step 200 The step of may include: subtracting the scattering signal from the detection signal to obtain the penetration signal. Since the positions of the first detector module 20 and the second detector module 30 are close and have the same performance, the received scattered signals are also very close. Therefore, the penetration signal can be approximately obtained by subtracting the scattered signal from the detection signal.

For the case where the detector modules of the first detector array 2 and the second detector array 3 have different specifications, numbers, or arrangement positions, etc., or considering the offset of the second detector array 3 relative to the first detector array 2 In other embodiments, referring to FIG. 8, the step of scatter correction in step 200 may include: step 210 and step 230. In step 210, the scatter signal is converted according to the preset relationship between the scatter signal detection capabilities of the first detector array 2 and the second detector array 3 to obtain a converted scatter signal. In step 230, the converted scatter signal is subtracted from the detection signal to obtain the penetration signal.

In order to determine the foregoing predetermined relationship, in some embodiments, the scatter correction method further includes: calibrating the predetermined relationship between the scatter signal detection capabilities of the first detector array 2 and the second detector array 3 . The expression of the preset relationship can be: RSSI _C =a*RSSI _O ; where RSSI _O is the signal intensity of the scattered signal detected by the second detector array 3, and RSSI _C is the converted signal of the scattered signal Strength, a is the scale factor. In order to prevent the consistency of each detection unit and excessive correction caused by signal fluctuations, in some embodiments, the scale factor a is greater than 0 and less than 1.

5 and 6, the first detector module 20 may include a plurality of first detection units, and the second detector module 30 may include a plurality of second detection units. Considering that the edge detection unit 21 in the first detector module 20 (that is, the detection unit at the outermost edge of the multiple detection units along the arrangement direction of the multiple detection units) is more significantly affected by the scattered signal than the non-edge detection unit 22, so When the scatter signal is converted, the proportional coefficient corresponding to the edge detection unit 31 in the plurality of second detection units is greater than the proportional coefficient corresponding to the non-edge detection unit 32 in the plurality of second detection units.

Referring to FIG. 9, in order to reduce the fluctuation of the scattered signal (ie scattered noise) of one or several detection units in the second detector array, in some embodiments, step 220 may be added on the basis of FIG. 8 , That is, after step 210, smoothly denoise the converted scattering signal, and use the smoothed and denoised scattering signal as the converted scattering signal. And in step 230, the scatter signal after smoothing and denoising is used as the scatter signal after conversion and removed from the detection signal.

Figure 12 is the detection signal received by the first detector array in some embodiments of the radiation inspection system of the present disclosure, the scatter signal detected by the second detector array and converted and smoothed and denoised, and the scatter signal obtained after the scatter correction of the scatter signal Schematic diagram of the signal strength of the penetration signal.

The signal intensity curve of the detection signal of the first detector array (as the main detector array) and the signal intensity curve of the scattering signal of the second detector array (as the scattering detector array) are respectively shown in FIG. 12. In the scatter correction process, the signal intensity of the scatter signal is multiplied by the scale factor 0.9, and then the result is smoothed, and then the signal intensity of the detection signal is subtracted from the result of the smoothing process to obtain the corrected first detector array Detection signal.

Through the scatter correction of the embodiment of the ray inspection system of the present disclosure, Fig. 13 (a) and (b) respectively show the penetration image generated by the first detector array without scatter correction and the penetrating power image after scatter correction. Throughput image for comparison. It can be seen from Figure 13(a) that the image is disturbed by scattering, the upper and lower edges of the steel plate are brighter, and at the same time, the image of the lead block on the back side of the steel plate is missing. After the image in (b) of FIG. 13 is subjected to scattering correction, the brightness and darkness of the steel plate are relatively uniform, and the image of the lead block is relatively complete.

So far, the various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

A radiographic inspection system, including:

The ray source (1) is configured to generate a beam of rays (10);

The first detector array (2) is at least partially located within the coverage area of the ray beam (10);

The second detector array (3) is located on the same side of the inspection object (4) of the radiation inspection system as the first detector array (2), and is located outside the coverage of the radiation beam (10) , The second detector array (3) is configured to receive the scattering signal of the ray beam (10) in the process of passing through the inspection object (4); and

The processor (5) is in signal connection with the first detector array (2) and the second detector array (3), and is configured to perform processing on the first detector array (2) according to the scattering signal The received signal is subjected to scatter correction.
The radiographic inspection system according to claim 1, wherein the first detector array (2) includes at least one set of first detector modules (20), and each set of first detector modules (20) includes at least one set of first detector modules (20). A plurality of first detector modules (20) arranged in the direction (x), the second detector array (3) includes at least one group of second detector modules (30), and each group of second detector modules (30) It comprises 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 ray beam (10).
The radiographic inspection system according to any preceding claim, wherein 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) is in one-to-one correspondence with each second detector module (30) in each group of second detector modules (30), and is in a one-to-one correspondence with the corresponding The positions of the second detector modules (30) in the first direction (x) are the same.
The radiographic inspection system according to any one of the preceding claims, wherein the second detector array (3) includes a set of second detector modules (30), the set of second detector modules (30) located in the first The detector array (2) is on one side of the second direction (y); or the second detector array (3) includes two sets of second detector modules (30), and the two sets of second detector modules ( 30) are respectively 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 ray beam (10).
The radiographic inspection system according to any preceding claim, wherein the first detector module (20) included in the first detector array (2) and the second detector included in the second detector array (3) are The modules (30) are all the same in specifications.
The radiographic inspection system according to any preceding claim, wherein the first detector module (20) included in the first detector array (2) and the second detector included in the second detector array (3) are The modules (30) are different in at least one of specifications, numbers, and arrangement positions.
The radiographic inspection system according to any preceding claim, wherein the distance (d) between the first detector array (2) and the second detector array (3) in the second direction (y) is greater than that of the The smallest pixel size in the sensitive area of the first detector array (2) and the sensitive area of the second detector array (3), the second direction (y) and the beam of the ray beam (10) The flow plane is vertical.
The radiographic inspection system according to any preceding claim, wherein the processor (5) is configured to detect the scattering signal of the first detector array (2) and the second detector array (3) The preset relationship between the calibrated.
The ray inspection system according to any preceding claim, wherein the ray beam (10) generated by the 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 beam (10) generated by the ray source (1) does not exceed 100mm.
A scatter correction method for a radiographic inspection system based on any of the preceding claims, comprising:

Receiving the detection signal detected by the first detector array (2), and receiving the scattering signal detected by the second detector array (3);

Performing scatter correction on the detection signal according to the scatter signal to obtain the corrected detection signal as a penetration signal when the ray beam (10) passes through the object to be inspected.
The scattering correction method according to any preceding claim, wherein the first detector module (20) included in the first detector array (2) and the second detector included in the second detector array (3) are The module (30) has the same specifications, quantity and arrangement position. The steps of scatter correction include:

The scattering signal is subtracted from the detection signal to obtain the penetration signal.
A method of scatter correction according to any preceding claim, wherein the step of scatter correction includes:

Converting the scattering signal according to the 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;

The converted scattering signal is subtracted from the detection signal to obtain the penetration signal.
The scattering correction method according to any preceding claim, further comprising:

The preset relationship between the detection capabilities of the scattered signal of the first detector array (2) and the second detector array (3) is calibrated.
The scattering correction method according to any preceding claim, wherein the expression of the predetermined relationship is:

RSSI C =a*RSSI O ;

Wherein, RSSI O is the signal intensity of the scattered signal detected by the second detector array (3), RSSI C is the signal intensity of the converted scattered signal, and a is the scale factor.
The scattering correction method according to any preceding claim, wherein the scale factor a is greater than 0 and less than 1.
The scattering correction method according to any preceding claim, wherein the first detector array (2) includes a plurality of first detector modules (20), and at least one of the plurality of first detector modules (20) A first detector module (20) includes a plurality of first detection units, the second detector array (3) includes a plurality of second detector modules (30), and the plurality of second detector modules (30) At least one second detector module (30) in) includes a plurality of second detection units;

When the scatter signal is converted, the proportional coefficient corresponding to the edge detection unit (31) in the plurality of second detection units is greater than that of the non-edge detection unit (32) in the plurality of second detection units. Scale factor.
The scattering correction method according to any one of the preceding claims, wherein, after converting the scattering signal, it further comprises:

Perform smoothing and denoising on the converted scattering signal, and use the smoothed and denoised scattering signal as the converted scattering signal.