X-ray inspection apparatus

Abstract

To provide an X-ray inspection device capable of obtaining two images of different energy bands by one X-ray detection part.SOLUTION: The X-ray inspection device 1 includes a conveyance unit 5, an X-ray irradiation unit 6 configured to irradiate the article G conveyed by the conveyance unit 5 with X-rays, a filter unit 8 configured to reduce a part of energy included in the X-rays transmitted through the article G, a sensor unit 7 including a plurality of detection elements 11 configured to detect the first X-rays transmitted through the article G and the second X-rays transmitted through the article G and the filter unit 8, respectively, and a control unit 9 configured to specify the detection elements 11 that have detected the first X-rays and the second X-rays in the sensor unit 7 and generate a first image P1 based on the first X-rays of the first energy band based on a result of the specification by the control unit 9. An image generation part 23 for generating a second image P2 on the basis of a second X-ray in a second energy bin different from the first energy bin, and an inspection part 24 for inspecting qualities of the articles G on the basis of the first image P1 and the second image P2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an X-ray inspection apparatus. [Background technology]

[0002] Patent Document 1 discloses an X-ray inspection device comprising: a conveying means for conveying an object to be inspected on a conveying surface; a first X-ray source and a second X-ray source for irradiating the object to be inspected conveyed on the conveying surface with X-rays of different intensities; a first X-ray line sensor and a second X-ray line sensor arranged at positions opposite the first X-ray source and the second X-ray source across the conveying surface, and for outputting first X-ray image data corresponding to the X-rays irradiated from the first X-ray source and passing through the object to be inspected, and a second X-ray line sensor respectively corresponding to the X-rays irradiated from the second X-ray source and passing through the object to be inspected; an image synthesis means for synthesizing the first X-ray image data and the second X-ray image data and outputting the data as a single image data corresponding to the object to be inspected; and a determination means for determining the presence or absence of a foreign object in the object to be inspected based on the image data output by the image synthesis means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-194100 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned X-ray inspection device is equipped with two X-ray irradiation units (X-ray sources) and two X-ray detection units (line sensors), thereby generating images based on two X-rays in different energy bands, and inspecting an item (inspection subject) using the two images. In this configuration with two X-ray detection units, it is necessary to align the two X-ray detection units, adjust the time difference, etc., which results in poor operability for settings, etc. Therefore, from the viewpoint of operability, etc., it is preferable that the X-ray inspection device has a single (integrated) X-ray detection unit. However, if there is only one X-ray detection unit, it is not possible to obtain two images in different energy bands.

[0005] An object of one aspect of the present invention is to provide an X-ray inspection apparatus that can obtain two images in different energy bands using a single X-ray detection unit. [Means for solving the problem]

[0006] (1) An X-ray inspection device according to one aspect of the present invention includes a conveying unit that conveys an article along a conveying direction, an X-ray irradiation unit that irradiates X-rays onto the article being conveyed by the conveying unit, a filter unit that reduces some of the energy contained in the X-rays that have passed through the article, an X-ray detection unit having a plurality of detection elements that detect first X-rays that have passed through the article and second X-rays that have passed through the article and the filter unit, an image generation unit that identifies the detection elements that detected the first X-rays and the second X-rays among the detection elements that detected the X-rays in the X-ray detection unit, and generates a first image based on the first X-rays in a first energy band and generates a second image based on the second X-rays in a second energy band different from the first energy band, and an inspection unit that inspects the quality of the article based on the first image and the second image.

[0007] An X-ray inspection device according to one aspect of the present invention includes a filter unit that reduces a portion of the energy contained in X-rays that have passed through an object. As a result, in the X-ray inspection device, the detection elements of the X-ray detection unit detect first X-rays that have passed through the object and second X-rays that have passed through the object and the filter unit. With this configuration, the image generation unit identifies the detection elements that detected the first X-rays and the second X-rays, and, based on the identification results, generates a first image based on the first X-rays in a first energy band and a second image based on the second X-rays in a second energy band different from the first energy band. Therefore, in the X-ray inspection device, two images in different energy bands can be obtained using a single X-ray detection unit.

[0008] (2) In the X-ray inspection device of (1) above, the plurality of detecting elements may be arranged in a cross direction that crosses horizontally the conveying direction, and the filter unit may change the number of rows of detecting elements that reduce energy. In this configuration, the filter unit may change the number of rows of detecting elements to match the brightness of the first image and the second image.

[0009] (3) In the X-ray inspection device described in (2) above, the plurality of detection elements may include a first detection element that detects a first X-ray and a second detection element that detects a second X-ray, and the image generation unit may not use a detection result detected by at least one of the first detection element and the second detection element that are adjacent to each other in the intersecting direction for image generation. Depending on the attachment position of the filter unit, the first detection element and the second detection element may not be clearly distinguishable in a region where the first detection element and the second detection element are adjacent to each other. Therefore, by not using a detection result detected by at least one of the adjacent first detection element and the second detection element for image generation, the first image and the second image for each energy band can be generated with high accuracy.

[0010] (4) In the X-ray inspection apparatus of (2) or (3), the plurality of detector elements may include detector elements arranged in a first row along the intersecting direction and detector elements arranged in a second row parallel to the first row, and the length of the detector elements in the first row in the intersecting direction may be longer than the length of the detector elements in the second row. This configuration makes it less likely that a foreign object will go undetected.

[0011] (5) In any one of the X-ray inspection devices (1) to (4) above, the inspection unit may select either the first image or the second image based on the conveying speed of the conveying unit, and inspect the quality of the article based on that image. In this configuration, even if the conveying speed increases, for example, only one image is selected, so it is possible to avoid a situation where the processing capacity cannot keep up with the conveying speed.

[0012] (6) In any one of the X-ray inspection devices (1) to (5) above, the inspection unit may inspect the quality of the article based on a composite image obtained by combining the first image and the second image. With this configuration, differences in brightness, contrast, etc. between the first image and the second image can be reduced, thereby enabling the quality of the article to be inspected with high accuracy.

[0013] (7) In any one of the X-ray inspection devices (1) to (6) above, an identification unit may be provided that identifies the first X-ray and the second X-ray from the X-rays detected by the detection elements using a predetermined threshold. With this configuration, the first X-ray and the second X-ray can be identified, and therefore the first image and the second image can be generated appropriately. [Effects of the Invention]

[0014] According to one aspect of the present invention, two images in different energy bands can be obtained using one X-ray detection unit. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a configuration diagram of an X-ray inspection apparatus according to an embodiment. [Figure 2]FIG. 2 is a schematic diagram showing the internal configuration of the shielding box shown in FIG. [Figure 3] FIG. 3 is a schematic plan view of the main part of the sensor unit. [Figure 4] FIG. 4 is a schematic plan view showing the arrangement of the filter section relative to the sensor section. [Figure 5] FIG. 5 is a functional configuration diagram of the control unit. [Figure 6] 6(a) and 6(b) are diagrams showing transmission images. [Figure 7] FIG. 7 is a schematic plan view showing the arrangement of the filter section relative to the sensor section. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0017] As shown in Fig. 1, the X-ray inspection apparatus 1 includes an apparatus main body 2, support legs 3, a shielding box 4, a conveying unit 5, an X-ray irradiation unit 6, a sensor unit (X-ray detection unit) 7, a filter unit 8, a display operation unit 9, and a control unit 10. The X-ray inspection apparatus 1 generates an X-ray transmission image of the item G while conveying the item G, and inspects the item G based on the X-ray transmission image. The item G before inspection is carried into the X-ray inspection apparatus 1 by a carry-in conveyor 51. The item G after inspection is carried out of the X-ray inspection apparatus 1 by a carry-out conveyor 52.

[0018] The device main body 2 houses the control unit 10 and the like. The support legs 3 support the device main body 2. The shielding box 4 is provided on the device main body 2. The shielding box 4 is a housing that prevents leakage of X-rays (electromagnetic waves) to the outside. Inside the shielding box 4 is provided an inspection room R where inspection of items G is carried out using X-rays. The shielding box 4 is formed with an entrance 4a and an exit 4b. Items G before inspection are carried into the inspection room R from the entrance 4a on the carry-in conveyor 51. After inspection, the items G are carried out from the inspection room R to the exit conveyor 52 via the exit 4b.

[0019] The conveying unit 5 is a member that conveys the article G, and is disposed so as to penetrate the center of the shielding box 4. The conveying unit 5 conveys the article G in a conveying direction A from the entrance 4a through the inspection room R to the exit 4b. The speed (conveying speed) at which the article G is conveyed by the conveying unit 5 is set, for example, by the control unit 10. The conveying unit 5 is, for example, a belt conveyor stretched between the entrance 4a and the exit 4b. Note that the conveying unit 5 may protrude outward beyond the entrance 4a and the exit 4b.

[0020] As shown in FIGS. 1 and 2, the X-ray irradiator 6 is an electromagnetic wave irradiator located within the shield box 4 and irradiates the object G transported by the transport unit 5 with X-rays. The X-rays include X-rays in various energy ranges, from low energy (long wavelength) to high energy (short wavelength). Therefore, the X-ray irradiator 6 irradiates the object G transported by the transport unit 5 with X-rays in multiple energy ranges. X-ray irradiation by the X-ray irradiator 6 (i.e., idling of the X-ray irradiator 6) may be performed after the X-ray inspection device 1 is started and before the inspection of the object G. Note that the terms "low" and "high" in the above-mentioned terms "low energy" and "high energy" refer to relatively "low" and "high" in the multiple energy ranges irradiated by the X-ray irradiator 6, and do not refer to a specific range. The power (particularly, the current) supplied to the X-ray irradiator 6 can be changed manually or automatically. By changing the power, the output of the X-rays irradiated to the object G can be changed. This allows X-rays with an appropriate intensity to be irradiated to the object G.

[0021] The sensor unit 7 is a sensor unit that detects electromagnetic waves. The sensor unit 7 is disposed inside the shielding box 4 at a position facing the X-ray irradiation unit 6 in the vertical direction. The transport unit 5 is disposed between the sensor unit 7 and the X-ray irradiation unit 6 in the vertical direction. FIG. 3 is a schematic plan view of the main parts of the sensor unit 7. As shown in FIG. 3, the sensor unit 7 detects X-rays and has a plurality of detection elements 11 that are arranged in a plane (two-dimensionally). The detection elements 11 are arranged at least in a direction (intersecting direction) that intersects with the transport direction A of the transport unit 5.

[0022] In this embodiment, the sensor unit 7 is a direct conversion type detection unit capable of detecting X-rays by a photon counting method. The detection element 11 is, for example, a sensor (multi-energy sensor) that detects X-rays in each of a plurality of energy ranges that pass through the article G, and the sensor unit 7 may also be a time delay integration sensor (TDI sensor). The detection element 11 includes, for example, a photon detection sensor such as a CdTe semiconductor detector. In the detection element 11, electron-hole pairs are generated, for example, when X-ray photons reach the detection element 11. Photon counting (photon counting) is performed based on the energy (photon energy) obtained at this time. The counting process is performed, for example, by a calculation unit (not shown) included in the sensor unit 7 or the detection element 11. The results (detection results) of the counting process for each detection element 11 by the calculation unit are output to the control unit 10 at predetermined time intervals, for example. The predetermined time is a time (default time) that is predetermined for the X-ray inspection apparatus 1. The predetermined time interval described above is also called a read interval or a delay time, and can be changed by the control unit 10 as appropriate.

[0023] The multiple detection elements 11 include first detection elements 12 arranged in a first row C1 in the intersecting direction and second detection elements 13 arranged in a second row C2 parallel to the first row C1. Therefore, the first row C1 has multiple first detection elements 12 arranged along the intersecting direction, and the second row C2 has multiple second detection elements 13 arranged along the intersecting direction. In the sensor unit 7, the first row C1 and the second row C2 are arranged alternately along the conveying direction A. In other words, the sensor unit 7 has multiple first rows C1 and multiple second rows C2, and the first row C1 and the second row C2 are arranged alternately in the conveying direction A. Therefore, the first detection elements 12 and the second detection elements 13 are arranged alternately in the conveying direction A. Each of the first row C1 and the second row C2 may function as a pseudo line sensor, for example. While FIG. 3 shows two first rows C1 and two second rows C2, three or more first rows C1 and two second rows C2 may be provided.

[0024] In this embodiment, the dimension D1 of the first detection element 12 in the conveying direction A is the same as the dimension D2 of the second detection element 13 in the conveying direction A, but is not limited to this. The dimension D3 of the first detection element 12 in the cross direction is different from the dimension D4 of the second detection element 13 in the cross direction. In this embodiment, the dimension D3 is larger than the dimension D4. For example, the dimension D3 is a natural number multiple of the dimension D4 that is 2 or more. The dimensions D1 and D3 are preferably, for example, 1.0 mm or less, and more preferably 0.1 mm to 0.9 mm. The dimensions D1 and D3 are most preferably, for example, 0.3 mm. The dimensions D2 and D4 are preferably 1.0 mm or less, and more preferably 0.1 mm to 0.9 mm.

[0025] When the number of first detection elements 12 in the first column C1 is the same as the number of second detection elements 13 in the second column C2, the brightness, contrast, etc. of an image generated using the detection results output from the second column C2 may be significantly different from the image generated using the detection results output from the first column C1. For this reason, in this embodiment, the number of second detection elements 13 arranged in the second column C2 is greater than the number of first detection elements 12 arranged in the first column C1. For example, the number of second detection elements 13 arranged in the second column C2 is a natural number multiple of the number of first detection elements 12 arranged in the first column C1, which is two or more. Alternatively, the value obtained by dividing the number of second detection elements 13 arranged in the second column C2 by the number of first detection elements 12 arranged in the first column C1 may be the same as the value obtained by dividing the dimension D3 by the dimension D4.

[0026] The dimension L1 of the gap G1 between the first detection elements 12 in the cross direction may be the same as or different from the dimension L2 of the gap G2 between the second detection elements 13 in the cross direction. In this embodiment, the dimension L1 is larger than the dimension L2. In this case, a portion of the second detection element 13 overlaps the gap G1 as viewed from the conveying direction A. For example, two adjacent second detection elements 13 overlap as viewed from the conveying direction A. This allows a foreign object to pass over one or more second detection elements 13 even if the dimensions L1 and L2 are the same. Alternatively, a portion of the second detection element 13 may overlap the gap G1 as viewed from the conveying direction A. In other words, regardless of the relationship between the dimensions L1 and L2, the first detection element 12 may overlap multiple second detection elements 13 in the conveying direction A.

[0027] As shown in FIG. 2, the filter unit 8 reduces a portion of the energy contained in the X-rays that have passed through the article G. The filter unit 8 is, for example, a metal plate. The filter unit 8 has a predetermined thickness. The material and thickness of the filter unit 8 can be set appropriately depending on the article G. In this embodiment, the filter unit 8 is disposed between the X-ray irradiation unit 6 and the sensor unit 7, at a position close to the sensor unit 7. A predetermined gap may be provided between the sensor unit 7 and the filter unit 8.

[0028] 4, the filter unit 8 is arranged so as to cover a portion of the sensor unit 7. In this embodiment, the filter unit 8 is arranged so as to cover a portion of the sensor unit 7 on the upstream side in the conveying direction A. The filter unit 8 is arranged so that the ends of the filter unit 8 (the ends in the conveying direction A) do not overlap with the detecting elements 11 (first detecting element 12, second detecting element 13) of the sensor unit 7 when viewed in a direction perpendicular to the surface of the filter unit 8 (the vertical direction).

[0029] The filter unit 8 is arranged to cover a portion of the sensor unit 7 so that the brightness of an image generated using the detection results output from the detection elements 11 of the sensor unit 7 covered by the filter unit 8 is equivalent to the brightness of an image generated using the detection results output from the detection elements 11 of the sensor unit 7 that are not covered by the filter unit 8. The brightness of an image generated using the detection results output from the detection elements 11 of the sensor unit 7 covered by the filter unit 8 may be darker than the brightness of an image generated using the detection results output from the detection elements 11 of the sensor unit 7 that are not covered by the filter unit 8. Therefore, in the example shown in FIG. 4 , the area of ​​the sensor unit 7 covered by the filter unit 8 is larger than the area of ​​the sensor unit 7 that is not covered by the filter unit 8. In other words, the area of ​​the sensor unit 7 that is not covered by the filter unit 8 is smaller than the area of ​​the sensor unit 7 that is covered by the filter unit 8.

[0030] The sensor unit 7 detects the first X-rays that have passed through the article G and the second X-rays that have passed through the article G and the filter unit 8. The sensor unit 7 detects the first X-rays in the detection elements 11 that are not covered by the filter unit 8. The sensor unit 7 detects the second X-rays in the detection elements 11 that are covered by the filter unit 8.

[0031] As shown in FIG. 1, the display operation unit 9 is a component (display unit) provided in the device main body 2. The display operation unit 9 displays various information and accepts input operations of various conditions from the outside. The display operation unit 9 is, for example, a liquid crystal display, and displays an operation screen as a touch panel. In this case, the operator can input various conditions via the display operation unit 9. For example, the operator can set the transport speed of the transport unit 5, the power (at least one of current and voltage) supplied to the X-ray irradiation unit 6, etc. via the display operation unit 9. The input operations accepted by the display operation unit 9 are output to the transport unit 5, the sensor unit 7, the control unit 10, etc.

[0032] The control unit 10 is disposed inside the device main body 2. The control unit 10 controls the operation of each part of the X-ray inspection device 1. The control unit 10 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The ROM stores programs for controlling the X-ray inspection device 1, operation modes of the X-ray inspection device 1, etc.

[0033] 5 is a functional configuration diagram of the control unit 10. As shown in FIG. 5, the control unit 10 includes a receiving unit 21, an identifying unit 22, an image generating unit 23, an inspecting unit 24, a determining unit 25, an output unit 26, and a recording unit 27.

[0034] The receiving unit 21 receives an input operation accepted by the display operation unit 9. The receiving unit 21 receives, for example, the transport speed of the transport unit 5 set via the display operation unit 9. The receiving unit 21 also receives the detection results output from the sensor unit 7 (specifically, the detection results of X-rays output from each detection element 11). The receiving unit 21 transmits the received detection results to the image generation unit 23.

[0035] The identification unit 22 identifies the first X-ray and the second X-ray from the X-rays detected by the detection elements 11 of the sensor unit 7 using a predetermined threshold. Based on the detection results of the sensor unit 7, the identification unit 22 identifies the detection elements 11 that detected the first X-ray and the second X-ray, among the multiple detection elements 11 (first detection element 12, second detection element 13), using a predetermined threshold. The predetermined threshold may be an average value or a difference value of the detected amounts of the first X-ray and the second X-ray. The threshold may be set automatically based on the output, or may be set manually by an operator on the setting screen of the display operation unit 9. The threshold is changeable. The identification unit 22 outputs the identification result to the image generation unit 23. The identification unit 22 may add information regarding the presence or absence of the filter unit 8 to the identification result (output value) from the sensor unit 7 and transmit it to the image generation unit 23.

[0036] The image generation unit 23 is mainly composed of, for example, a GPU (Graphics Processing Unit) and generates an image based on the detection results output from the sensor unit 7. For example, the image generation unit 23 expands the received signals of the detection results into a two-dimensional image in memory. The memory in which the two-dimensional image is expanded is, for example, a memory included in the GPU, but is not limited to this. The image generation unit 23 reads out, for example, the detection results output from at least some of the multiple detection elements 11 included in the sensor unit 7 at a predetermined read interval, and generates one or more time delay integrated images used for inspecting the item G. For example, the image generation unit 23 generates multiple transmission images corresponding to each of the multiple energy regions. The image generation unit 23 may also generate one or more difference images from the multiple transmission images.

[0037] The image generation unit 23 may use, for example, an image processing algorithm or a program that is automatically set by machine learning. The image processing algorithm is composed of one image processing filter or a combination of multiple image processing filters. At least one of the multiple image processing algorithms can be automatically generated from multiple image processing filters based on the specifications of the X-ray inspection device 1, the inspection conditions, etc., by employing a genetic algorithm (GA), which is a method that applies the mechanisms of heredity and evolution in the biological world.

[0038] At least some of the multiple image processing algorithms can also be set by the operator as appropriate via the display operation unit 9. The program automatically set by machine learning is a predictive model (trained model) generated by machine learning, and is an inference program incorporating parameters obtained as a result of machine learning (trained parameters). Examples of machine learning used in the trained model include neural networks, support vector machines, and genetic algorithms.

[0039] As shown in Figures 6(a) and 6(b), the image generation unit 23 generates a first image P1 (see Figure 6(a)) based on first X-rays in a first energy band based on the identification result by the identification unit 22, and generates a second image P2 based on second X-rays in a second energy band different from the first energy band. The first energy band is a lower energy band (low energy band) than the second energy band. The second energy band is a higher energy band (high energy band) than the first energy band. The first image P1 has a relatively low contrast and is bright overall. The second image P2 has a relatively high contrast and is dark overall.

[0040] One pixel included in the first image P1 and the second image P2 is generated, for example, using the detection result of a predetermined first detection element 12 in one or more first columns C1. The predetermined first detection element 12 is the first detection element 12 located at a predetermined position counting from one end of the first column C1 in the cross direction. Similarly, one pixel included in the first image P1 and the second image P2 is generated, for example, using the detection results of multiple predetermined second detection elements 13 in one or more second columns C2. The pixel is generated by adding up the detection results of two or more second detection elements 13 in one or more second columns C2 and using the summation result. The image generation unit 23 may generate a difference image (synthesized image) from the first image P1 and the second image P2.

[0041] The image generation unit 23 does not use the detection results of at least one of the first detection elements 12 and the second detection elements 13 that are adjacent in the intersecting direction for image generation. In this embodiment, the image generation unit 23 does not use the detection results of both the first detection element 12 and the second detection element 13 that are adjacent in the intersecting direction for image generation. Specifically, in this embodiment, as shown in FIG. 7, the image generation unit 23 does not use the detection results of both the first detection element 12 (first column C1) and the second detection element 13 (second column C2) (parts filled in gray) that are adjacent in the intersecting direction for image generation.

[0042] The inspection unit 24 inspects the quality of the item G based on the image generated by the image generation unit 23. For example, the inspection unit 24 inspects the quality of the item G using the first image P1, the second image P2, a difference image, etc. The inspection unit 24 may inspect the item G based on both the difference image and the first image P1 and the second image P2. While the difference image is being generated by the image generation unit 23, inspection of the item G based on the first image P1, the second image P2, etc. In this embodiment, the inspection unit 24 selects either the first image P1 or the second image P2 based on the conveying speed of the conveying unit 5, and inspects the quality of the item G based on that image. When the conveying speed of the conveying unit 5 is equal to or greater than a predetermined threshold, the inspection unit 24 selects either the first image P1 or the second image P2.

[0043] The inspection unit 24 inspects the quality of the item G, for example, whether or not there are foreign objects, cracks, or chips in the item G, but is not limited to this. When the item G is wrapped in a sheet-like packaging material, the inspection unit 24 can also inspect for tears in the packaging material, defective sealing of the packaging material (seal bite), etc. When the item G is contained in a package, the inspection unit 24 can perform inspections to check for foreign objects, missing items, the number of items contained, and hollow spaces in the package. The inspection unit 24 transmits the inspection results of the item G to the determination unit 25 and the recording unit 27.

[0044] The determination unit 25 determines whether the item G is a non-defective item based on the inspection results received from the inspection unit 24. For example, the determination unit 25 determines whether there is any foreign matter in the item G, whether there is any crack or chip in the item G, etc. The determination unit 25 transmits the determination result to the output unit 26 and the recording unit 27.

[0045] The output unit 26 outputs the determination result of the determination unit 25 to at least one of a portion of the X-ray inspection apparatus 1 other than the control unit 10 and a device different from the X-ray inspection apparatus 1. This allows at least one of the X-ray inspection apparatus 1 and a device different from the X-ray inspection apparatus 1 (for example, a sorting device arranged downstream of the X-ray inspection apparatus 1) to perform an operation when the item G is a defective product. Other examples of the device different from the X-ray inspection apparatus 1 include an input conveyor 51, an output conveyor 52, an alarm device, etc.

[0046] The recording unit 27 records signals, data, etc. generated by the control unit 10. For example, the recording unit 27 records the detection results transmitted from the receiving unit 21, image data transmitted from the image generating unit 23, data related to the inspection results transmitted from the inspecting unit 24, and data related to the judgment results transmitted from the judging unit 25.

[0047] As described above, the X-ray inspection apparatus 1 according to this embodiment includes a filter unit 8 that reduces a portion of the energy contained in the X-rays that have passed through the article G. As a result, in the X-ray inspection apparatus 1, the detection elements 11 of the sensor unit 7 detect the first X-rays that have passed through the article G and the second X-rays that have passed through the article G and the filter unit 8. With this configuration, the image generation unit 23 identifies the detection elements 11 that detected the first X-rays and the second X-rays, and based on the identification results, generates a first image P1 based on the first X-rays in a first energy band, and generates a second image P2 based on the second X-rays in a second energy band that is different from the first energy band. Therefore, in the X-ray inspection apparatus 1, two images in different energy bands can be obtained using a single sensor unit 7.

[0048] In the X-ray inspection apparatus 1 according to the present embodiment, the filter unit 8 changes the number of rows of the detection elements 11 that reduce energy. In this configuration, the filter unit 8 changes the number of rows of the detection elements 11, thereby making it possible to match the brightness of the first image P1 and the second image P2.

[0049] In the X-ray inspection apparatus 1 according to this embodiment, the inspection unit 24 selects either the first image P1 or the second image P2 based on the conveying speed of the conveying unit 5, and inspects the quality of the article G based on that image. In this configuration, even if the conveying speed increases, for example, only one image is selected, so it is possible to avoid a situation where the processing capacity cannot keep up with the conveying speed.

[0050] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0051] In the above embodiment, the multiple detection elements 11 of the sensor unit 7 include the first detection elements 12 and the second detection elements 13 of different sizes. However, the detection elements may all be of the same type and of the same size.

[0052] In the above embodiment, the sensor unit is a device capable of detecting X-rays by a photon counting method, but is not limited to this. The detection element included in the sensor unit may have at least a scintillator and a photodiode. [Explanation of symbols]

[0053] 1...X-ray inspection device, 5...conveying section, 6...X-ray irradiation section, 7...sensor section (X-ray detection section), 8...filter section, 11...detecting element, 12...first detecting element, 13...second detecting element, 22...identifying section, 23...image generating section, 24...inspection section, A...conveying direction, C1...first row, C2...second row, G...item, P1...first image, P2...second image.

Claims

1. a conveying unit that conveys the article along a conveying direction; an X-ray irradiation unit that irradiates the object conveyed by the conveying unit with X-rays; a filter unit that reduces a portion of the energy contained in the X-rays that have passed through the article; an X-ray detection unit having a plurality of detection elements that detect first X-rays that have passed through the article and second X-rays that have passed through the article and the filter unit; an image generating unit that identifies the detecting elements that detected the first X-ray and the second X-ray among the detecting elements that detected the X-ray in the X-ray detection unit, and generates a first image based on the first X-rays in a first energy band and a second image based on the second X-rays in a second energy band different from the first energy band based on the identification result; an inspection unit that inspects the quality of the item based on the first image and the second image.

2. The plurality of detection elements are arranged in a cross direction that crosses the conveying direction horizontally, The X-ray inspection apparatus according to claim 1 , wherein the filter section changes the number of rows of the detection elements that reduce the energy.

3. the plurality of detection elements include a first detection element that detects the first X-ray and a second detection element that detects the second X-ray; The X-ray inspection apparatus according to claim 2 , wherein the image generation unit does not use a detection result detected by at least one of the first detection element and the second detection element adjacent to each other in the intersecting direction for image generation.

4. The plurality of detection elements include detection elements arranged in a first row along the cross direction; a second row of detector elements arranged in parallel with the first row; The X-ray inspection apparatus according to claim 2 , wherein a length of the detecting elements in the first row in the intersecting direction is longer than a length of the detecting elements in the second row in the intersecting direction.

5. 3. The X-ray inspection apparatus according to claim 1, wherein the inspection unit selects either the first image or the second image based on a conveying speed of the conveying unit, and inspects the quality of the item based on the selected image.

6. The X-ray inspection apparatus according to claim 1 , wherein the inspection unit inspects the quality of the article based on a composite image obtained by combining the first image and the second image.

7. 3 . The X-ray inspection apparatus according to claim 1 , further comprising: an identifying unit that identifies the first X-ray and the second X-ray from the X-rays detected by the detection elements using a predetermined threshold value.

Images