X-ray inspection apparatus

Abstract

To provide an X-ray inspection device, an X-ray inspection system, and an X-ray inspection method capable of preventing deterioration of inspection accuracy of an article even if a conveyance speed of the article is increased.SOLUTION: The X-ray inspection apparatus includes a conveyor that conveys an article, an electromagnetic wave irradiator that irradiates the article with a first electromagnetic wave in a first energy band and a second electromagnetic wave in a second energy band, an electromagnetic wave sensor that detects the first electromagnetic wave and the second electromagnetic wave with which the article is irradiated, and a controller to which a detection result of the electromagnetic wave sensor is input. The control unit generates a first transmission image based on a detection result of the first electromagnetic wave and a second transmission image based on a detection result of the second electromagnetic wave, performs image processing including subtraction processing on the first transmission image and the second transmission image by using a luminance distribution related to a background other than the article shown in the first transmission image and the second transmission image, and determines presence or absence of a foreign substance contained in the article based on a difference image obtained by the subtraction processing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A known conventional X-ray inspection apparatus is, for example, that described in Patent Document 1. The X-ray inspection apparatus described in Patent Document 1 includes an X-ray source that irradiates an object to be inspected with X-rays, a sensor unit having a first sensor that detects X-rays in a first energy band irradiated from the X-ray source and a second sensor that detects X-rays in a second energy band, an image generation unit that generates a first transmission image of the object to be inspected based on X-ray data detected by the first sensor and a second transmission image of the object to be inspected based on X-ray data detected by the second sensor, and an inspection unit that performs inspection based on the image generated by the image generation unit. This X-ray inspection apparatus makes it possible to extract only foreign objects by erasing the object to be inspected from the first transmission image and the second transmission image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-73056 Summary of the Invention [Problem to be solved by the invention]

[0004] The X-ray inspection device described above is capable of extracting only foreign matter, as described above. Therefore, even if the object (item) to be inspected is thick, the presence or absence of foreign matter within the object can be inspected with high accuracy. On the other hand, if the object to be inspected includes a thin portion (such as a packaging material portion), it may not be possible to inspect the presence or absence of foreign matter within that portion with high accuracy.

[0005] An object of one aspect of the present invention is to provide an X-ray inspection apparatus that is capable of highly accurate inspection of articles having various thicknesses. [Means for solving the problem]

[0006] An X-ray inspection device according to one aspect of the present invention includes an X-ray source that irradiates an object with X-rays in multiple energy bands, an X-ray detection unit that can detect X-rays using a photon counting method, an image generation unit that generates an overall transmission image corresponding to all X-rays in the multiple energy bands and a transmission image corresponding to some of the X-rays in the multiple energy bands based on the X-ray detection results by the X-ray detection unit, and an inspection unit that inspects the object based on each of the overall transmission image and the transmission image.

[0007] According to this X-ray inspection device, the inspection unit inspects an object based on both the total transmission image and the transmission image. Here, the energy band for generating the transmission image is changed depending on the inspection conditions, thereby enabling accurate inspection of the presence or absence of foreign matter within the object. In addition, by using the total transmission image, the presence or absence of foreign matter can be inspected for objects of various thicknesses. Therefore, by using the above X-ray inspection device, high-precision inspection of objects of various thicknesses becomes possible.

[0008] An X-ray inspection apparatus according to another aspect of the present invention includes an X-ray source that irradiates an object with X-rays in a plurality of energy bands; an X-ray detection unit that can detect X-rays by a photon counting method; an image generation unit that generates, based on the X-ray detection results by the X-ray detection unit, (1) an entire transmission image corresponding to all X-rays in the plurality of energy bands, (2) a first transmission image corresponding to X-rays in a first energy band included in the plurality of energy bands, (3) a second transmission image corresponding to X-rays in a second energy band that is included in the plurality of energy bands and is lower than the first energy band, and (4) a difference image obtained by subtraction processing of the first transmission image and the second transmission image; and an inspection unit that inspects the object based on at least one of the entire transmission image, the first transmission image, and the second transmission image, and the difference image.

[0009] According to this X-ray inspection device, the inspection unit inspects the object based on at least one of the total transmission image, the first transmission image, and the second transmission image, as well as the differential image. In this case, by using the differential image, it is possible to accurately inspect the presence or absence of foreign matter in relatively thick portions of the object. In addition, by using at least one of the total transmission image, the first transmission image, and the second transmission image, it is possible to inspect the presence or absence of foreign matter in portions of the object other than the relatively thick portions. Therefore, by using the above X-ray inspection device, it is possible to inspect objects of various thicknesses with high accuracy.

[0010] The inspection unit may inspect the object based on the differential image and at least the total transmission image. In this case, by using the total transmission image, it is possible to easily inspect the presence or absence of foreign matter in objects of various thicknesses.

[0011] The inspection unit may inspect the article based on the differential image and at least the first transmission image. In this case, by using the first transmission image, it is possible to inspect with high accuracy whether or not there is a foreign substance, particularly in a thin portion of the article.

[0012] The inspection unit may inspect the article based on the differential image and at least the second transmission image. In this case, by using the second transmission image, it is possible to inspect the relatively thick part of the article for the presence or absence of foreign matter with higher accuracy.

[0013] The image generating section may generate the first transmission image based on the entire transmission image and the second transmission image.

[0014] The X-ray inspection device may further include a display unit that receives operations from an external device, and the display unit may receive an operation to select an image to be used in the inspection of an item by the inspection unit. In this case, the inspection accuracy, etc. can be appropriately changed via the display unit.

[0015] The X-ray detector may be a direct conversion type detector, which allows for miniaturization of the X-ray inspection device. [Effects of the Invention]

[0016] According to one aspect of the present invention, it is possible to provide an X-ray inspection apparatus that is capable of highly accurate inspection of articles having various thicknesses. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a configuration diagram of an X-ray inspection apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the internal configuration of the shielding box shown in FIG. [Figure 3] FIG. 3 is a functional configuration diagram of the control unit. [Figure 4] FIG. 4(a) is a diagram showing the first transmission image, and FIG. 4(b) is a diagram showing the second transmission image. [Figure 5] FIG. 5 is a diagram showing a difference image. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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.

[0019] 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, an X-ray detection unit 7, a display / operation unit 8, and a control unit 10. The X-ray inspection apparatus 1 generates an X-ray transmission image of the object G while conveying the object G, and performs inspection of the object G (e.g., inspection of the number of items stored, inspection of foreign matter, inspection of missing items, inspection of cracks and chips, etc.) based on the X-ray transmission image. The object G before inspection is carried into the X-ray inspection apparatus 1 by a carry-in conveyor 51. The object G after inspection is carried out of the X-ray inspection apparatus 1 by an unloading conveyor 52. The object G determined to be defective by the X-ray inspection apparatus 1 is sorted out of the production line by a sorting device (not shown) arranged downstream of the unloading conveyor 52. The object G determined to be non-defective by the X-ray inspection apparatus 1 passes through the sorting device as is. In this embodiment, the object G is cereal flakes.

[0020] 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 prevents leakage of X-rays (electromagnetic waves) to the outside. An inspection area R is provided inside the shielding box 4, where inspection of items G is carried out using X-rays. The shielding box 4 is formed with an inlet 4a and an outlet 4b. Items G before inspection are carried into the inspection area R from the inlet 4a of the carry-in conveyor 51. Items G after inspection are carried out from the inspection area R to the outlet 4b of the carry-out conveyor 52. An X-ray shielding curtain (not shown) is provided at each of the inlet 4a and the outlet 4b to prevent leakage of X-rays.

[0021] The transport unit 5 is a member that transports the article G and is arranged to pass through the center of the shielding box 4. The transport unit 5 transports the article G in the transport direction A from the entrance 4a through the inspection area R to the exit 4b. The transport unit 5 is, for example, a belt conveyor that is stretched between the entrance 4a and the exit 4b. Note that the transport unit 5, which is a belt conveyor, may protrude outward beyond the entrance 4a and the exit 4b.

[0022] As shown in FIGS. 1 and 2 , the X-ray irradiator 6 is an electromagnetic wave irradiator (X-ray source) disposed within the shield box 4. The X-ray irradiator 6 includes, for example, an X-ray tube that emits X-rays and a diaphragm that spreads the X-rays emitted from the X-ray tube in a fan shape within a plane perpendicular to the conveyance direction A. The X-rays irradiated from the X-ray irradiator 6 include X-rays in various energy bands ranging from low energy (long wavelength) to high energy (short wavelength). Therefore, the X-ray irradiator 6 irradiates the object G conveyed by the conveyance unit 5 with X-rays in multiple energy bands. Note that the terms “low” and “high” in the above-mentioned terms “low energy” and “high energy” indicate relatively “low” and “high” among the multiple energy bands irradiated from the X-ray irradiator 6, and do not indicate a specific range. In this embodiment, the X-ray irradiator 6 irradiates multiple energy bands including at least X-rays in a first energy band (first electromagnetic waves) and X-rays in a second energy band (second electromagnetic waves) lower than the first energy band. The first energy bin and the second energy bin may be distinguished by a predetermined threshold value, or by different threshold values ​​(for example, a first threshold value and a second threshold value different from the first threshold value). In the latter case, one or more energy bins may exist between the first energy bin and the second energy bin. The threshold values ​​and the number thereof can be changed as appropriate via the display operation unit 8 in response to changes in the type of article G, changes in inspection conditions, etc.

[0023] The X-ray detection unit 7 is a sensor member that detects electromagnetic waves. The X-ray detection unit 7 is located inside the shielding box 4, facing the X-ray irradiation unit 6 in the vertical direction. The X-ray detection unit 7 may be capable of detecting X-rays in a specific energy band, or may be capable of detecting X-rays using a photon counting method. The X-ray detection unit 7 may be a direct conversion type detection unit or an indirect conversion type detection unit. In this embodiment, the X-ray detection unit 7 is a direct conversion type detection unit that can detect X-rays using a photon counting method, and includes, for example, a sensor (multi-energy sensor) that detects X-rays in each of multiple energy bands that penetrate the item G. The sensors are, for example, arranged in a direction (width direction) perpendicular to at least the conveying direction and the vertical direction of the conveyor 5. The elements may be arranged not only in the width direction but also in the conveying direction. That is, the X-ray detection unit 7 may include a line sensor or a group of sensors arranged two-dimensionally. The sensors are, for example, photon detection sensors such as CdTe semiconductor detectors.

[0024] In the above elements included in the X-ray detection unit 7, for example, electron-hole pairs are generated when X-ray photons reach them. Photon counting is performed based on the energy obtained at this time. Here, photon counting in each energy range is possible by using a predetermined threshold (one or more thresholds). The X-ray detection unit 7 outputs a signal (detection result signal) corresponding to the X-ray detection result to the control unit 10.

[0025] As shown in FIG. 1, the display operation unit 8 is a component (display unit) provided in the device main body 2. The display operation unit 8 displays various information and accepts input operations of various conditions from the outside. The display operation unit 8 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 8. As an input operation, for example, the display operation unit 8 accepts an operation to select an image (described in detail later) to be used for inspection of the item G by the inspection unit 23 (see FIG. 3) included in the control unit 10. This allows the desired inspection results to be obtained in an optimal manner.

[0026] The control unit 10 is disposed within the apparatus main body 2. The control unit 10 controls the operations of each unit of the X-ray inspection apparatus 1 (in this embodiment, the transport unit 5, the X-ray irradiation unit 6, the X-ray detection unit 7, and the display operation unit 8, as well as a sorting device (not shown) disposed downstream of the X-ray inspection apparatus 1). The sorting device is a device that removes from the transport path an object to be inspected (item) that has been determined to be a defective product through image inspection by the X-ray inspection apparatus 1. The control unit 10 includes a processor such as a CPU (Central Processing Unit), memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and storage such as an SSD (Solid State Drive). A program for controlling the X-ray inspection apparatus 1 is recorded in the ROM.

[0027] 3 is a functional configuration diagram of the control unit 10. As shown in FIG. 3, the control unit 10 includes a detection result acquisition unit 21, an image generation unit 22, an inspection unit 23, a determination unit 24, an output unit 25, and a storage unit 26.

[0028] The detection result acquisition unit 21 acquires the detection result signal output from the X-ray detection unit 7. The detection result acquisition unit 21 transmits the acquired detection result signal to the image generation unit 22.

[0029] The image generation unit 22 is mainly composed of, for example, a GPU (Graphics Processing Unit) and expands the detection result signal 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 22 generates a plurality of images used for inspecting the item G, for example, based on the X-ray detection results by the X-ray detection unit 7. As one of the plurality of images, the image generation unit 22 generates, for example, a total transmission image (non-energy analysis image) corresponding to all X-rays in the plurality of energy bands based on the detection results. The total transmission image is generated, for example, based on all of the information included in the detection result signal. When generating the total transmission image, information considered to be noise may be excluded in advance. In this case, the total transmission image is generated based on a portion of the information included in the detection result signal.

[0030] The image generating unit 22 generates one or more transmission images corresponding to some of the X-rays in the plurality of energy bands in addition to the entire transmission image. In this embodiment, the image generating unit 22 generates, as the transmission images, a first transmission image P1 (see FIG. 4(a)) corresponding to the X-rays in the first energy band, a second transmission image P2 (see FIG. 4(b)) corresponding to the X-rays in the second energy band, and a difference image P3 (see FIG. 5) obtained by subtraction processing of the first transmission image P1 and the second transmission image P2.

[0031] The first transmission image P1 is generated based on, for example, a portion of the information included in the detection result signal. The second transmission image P2 is generated based on, for example, another portion of the information included in the detection result signal. The image generation unit 22 may generate the first transmission image P1 based on the entire transmission image and the second transmission image P2. In this case, the first transmission image P1 is generated based on, for example, difference data between data used to generate the entire transmission image and data used to generate the second transmission image P2. Alternatively, the image generation unit 22 may generate the second transmission image P2 based on the entire transmission image and the first transmission image P1. In this case, the second transmission image P2 is generated based on, for example, difference data between data used to generate the entire transmission image and data used to generate the first transmission image P1. The first transmission image P1 and the second transmission image P2 each depict an item G and a background other than the item G. As shown in an example in FIG. 4(a), the first transmission image P1 is brighter overall than the second transmission image P2. 4(b), the second transmission image P2 is darker overall than the first transmission image P1. In this embodiment, the comparison of the brightness between the first transmission image P1 and the second transmission image P2 corresponds to the comparison of the brightness of the article G displayed in the first transmission image P1 with the brightness of the article G displayed in the second transmission image P2.

[0032] The difference image P3 is an image (energy analysis image) generated by performing image processing on at least one of the first transmission image P1 and the second transmission image P2 using an image processing algorithm. The image processing algorithm is a template indicating the procedure for image processing to be performed on at least one of the first transmission image P1 and the second transmission image P2. The image processing algorithm is composed of one image processing filter or a combination of multiple image processing filters. The multiple image processing algorithms can be obtained externally via a network such as the Internet. The multiple image processing algorithms can also be obtained from an external storage medium such as a USB memory or a removable hard disk. 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 apparatus 1 or the inspection conditions, etc., using a genetic algorithm (GA), which is a method that applies the mechanisms of heredity and evolution in the biological world. At least some of the multiple image processing algorithms can also be set appropriately by an operator via the display operation unit 8. The image processing algorithm used for the first transmission image P1 and the image processing algorithm used for the second transmission image P2 may be different from each other. For example, to align the brightness of the first transmission image P1 with the brightness of the second transmission image P2, a process of changing the brightness of one of the first transmission image P1 and the second transmission image P2 may be performed. For example, a process using a luminance distribution as described in Japanese Patent Application No. 2021-195926 may be performed as this process.

[0033] Instead of using the image processing algorithm, the image generation unit 22 may use a program that is automatically set by machine learning. Such a program is a predictive model (trained model) generated by machine learning, and is an inference program that incorporates parameters (trained parameters) obtained as a result of machine learning. Examples of machine learning used in the trained model include neural networks, support vector machines, and genetic algorithms. The trained model may include a convolutional neural network or a neural network with multiple layers (e.g., eight or more layers). In other words, a trained model equivalent to the above program may be generated by deep learning.

[0034] The inspection unit 23 inspects the article G based on at least some of the multiple images generated by the image generation unit 22. The inspection unit 23 inspects the article G, for example, based on the entire transmission image and each of the above-mentioned transmission images. Alternatively, the inspection unit 23 inspects the article G based on at least one of the entire transmission image, the first transmission image P1, and the second transmission image P2, and the difference image P3. In other words, the inspection unit 23 inspects the article G based on two or more of the multiple images generated by the image generation unit 22. For example, the entire transmission image may be used from the perspective of utilizing a high-resolution image. For example, the first transmission image P1 may be used from the perspective of improving inspection accuracy for thin portions of the article G. For example, at least one of the second transmission image P2 and the difference image P3 may be used from the perspective of improving inspection accuracy for relatively thick portions of the article G.

[0035] In this embodiment, the inspection unit 23 inspects the item G using at least the difference image P3. When at least the difference image P3 is used, the inspection unit 23 may inspect the item G based on the difference image P3 and the full-transmission image, or may inspect the item G based on the difference image P3 and the first transmission image P1, or may inspect the item G based on the difference image P3 and the second transmission image P2. In the inspection unit 23, the inspection of the item G based on the difference image P3 and the inspection of the item G based on another image may be performed simultaneously or at different times. For example, the inspection of the item G based on the full-transmission image, etc. may be performed while the image generation unit 22 is generating the difference image P3.

[0036] The inspection unit 23 inspects the item G for, for example, the presence or absence of foreign matter, cracks, or chips, but is not limited to this. When the item G is wrapped in a sheet-like packaging material, the inspection unit 23 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 23 can perform inspections to check for foreign matter, missing items, the number of items contained, and hollow spaces within the package. The inspection unit 23 transmits the inspection results of the item G to the determination unit 24 and the memory unit 26.

[0037] The determination unit 24 determines whether the item G is a non-defective item based on the inspection results received from the inspection unit 23. For example, the determination unit 24 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 24 transmits the determination result to the output unit 25 and the memory unit 26.

[0038] The output unit 25 outputs the determination result of the determination unit 24 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.

[0039] The storage unit 26 records signals, data, etc. generated by the control unit 10. For example, the storage unit 26 records a detection result signal transmitted from the detection result acquisition unit 21, image data transmitted from the image generation unit 22, data related to the inspection result transmitted from the inspection unit 23, and data related to the judgment result transmitted from the judgment unit 24.

[0040] According to the X-ray inspection apparatus 1 of this embodiment described above, the inspection unit 23 inspects the article G based on at least one of the total transmission image, the first transmission image P1, and the second transmission image P2, and the difference image P3. In this case, by using the difference image P3, it is possible to inspect with high accuracy whether or not a foreign object is present in a relatively thick portion of the article G. In addition, by using at least one of the total transmission image, the first transmission image P1, and the second transmission image P2, it is possible to inspect with high accuracy whether or not a foreign object is present in a portion of the article G that is different from the relatively thick portion. Therefore, by using the X-ray inspection apparatus 1, it is possible to inspect with high accuracy articles having various thicknesses.

[0041] In addition, according to this embodiment, both non-energy analysis processing (analysis processing using at least one of the entire transmission image, the first transmission image P1, and the second transmission image P2) and energy analysis processing (analysis processing using the difference image P3) can be performed by a single X-ray inspection device. Therefore, by using the X-ray inspection device 1 on a production line, for example, it is possible to improve the inspection accuracy of the article G while realizing space savings, cost savings, energy savings, and the like.

[0042] In this embodiment, the inspection unit 23 may inspect the article G based on the differential image P3 and at least the total transmission image. In this case, by using the total transmission image, it is possible to easily inspect the presence or absence of foreign matter in articles G having various thicknesses.

[0043] In this embodiment, the inspection unit 23 may inspect the article G based on the difference image P3 and at least the first transmission image P1. In this case, by using the first transmission image P1, the inspection unit 23 can inspect with high accuracy the presence or absence of foreign matter, particularly in thin portions of the article G. In addition, in cases where the article G is wrapped in a sheet-like packaging material, the inspection unit 23 can inspect with high accuracy for tears in the packaging material, defective sealing of the packaging material (seal bite), and the like.

[0044] In this embodiment, the inspection unit 23 may inspect the article G based on the differential image P3 and at least the second transmission image P2. In this case, by using the second transmission image P2, it is possible to inspect the relatively thick portion of the article G for the presence or absence of foreign matter with higher accuracy.

[0045] In this embodiment, the image generating section 22 may generate the first transmission image P1 based on the entire transmission image and the second transmission image P2.

[0046] In this embodiment, the X-ray inspection apparatus 1 includes a display operation unit 8 that receives operations from outside, and the display operation unit 8 receives an operation to select an image to be used for inspecting the item G by the inspection unit 23. Therefore, the inspection accuracy and the like can be changed as appropriate via the display operation.

[0047] X-ray detection unit 7 may be a direct conversion type detection unit, in which case X-ray inspection apparatus 1 can be made smaller.

[0048] 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. For example, the present invention may relate to the following aspects. [A1] an X-ray source that irradiates an article with X-rays in multiple energy bands; an X-ray detection unit capable of detecting the X-rays by a photon counting method; an image generating unit that generates a whole transmission image corresponding to all X-rays in the plurality of energy bands and a transmission image corresponding to a part of X-rays in the plurality of energy bands based on the detection result of the X-rays by the X-ray detecting unit; an inspection unit that inspects the article based on the entire transmission image and the transmission image; An X-ray inspection device equipped with: [A2] an X-ray source that irradiates an article with X-rays in multiple energy bands; an X-ray detection unit capable of detecting the X-rays by a photon counting method; an image generating unit that generates, based on the X-ray detection results by the X-ray detection unit, (1) a total transmission image corresponding to all X-rays in the plurality of energy bands, (2) a first transmission image corresponding to X-rays in a first energy band included in the plurality of energy bands, (3) a second transmission image corresponding to X-rays in a second energy band included in the plurality of energy bands and lower than the first energy band, and (4) a difference image obtained by subtraction processing of the first transmission image and the second transmission image; an inspection unit that inspects the article based on at least one of the entire transmission image, the first transmission image, and the second transmission image, and the difference image; An X-ray inspection device equipped with: [A3] The X-ray inspection apparatus according to [A2], wherein the inspection unit inspects the item based on the difference image and at least the total transmission image. [A4] The X-ray inspection apparatus according to [A2] or [A3], wherein the inspection unit inspects the item based on the difference image and at least the first transmission image. [A5] The X-ray inspection apparatus according to [A2], wherein the inspection unit inspects the item based on the difference image and at least the second transmission image. [A6] The X-ray inspection apparatus according to any one of [A2] to [A5], wherein the image generating section generates the first transmission image based on the entire transmission image and the second transmission image. [A7] Further comprising a display unit that accepts operations from the outside, The X-ray inspection device according to any one of [A2] to [A6], wherein the display unit accepts a selection operation of an image used for inspection of the item by the inspection unit. [A8] The X-ray inspection apparatus according to any one of [A1] to [A7], wherein the X-ray detection unit is a direct conversion type detection unit.

[0049] In the above embodiment, the inspection unit inspects the object using at least the differential image, but this is not limited to this. For example, the inspection unit may inspect the object using at least the total transmission image. For example, the inspection unit may inspect the object based on the total transmission image and at least the first transmission image, or may inspect the object based on the total transmission image and at least the second transmission image, or may inspect the object based on the total transmission image and at least the differential image. In this case, since the total transmission image is always used, the presence or absence of foreign matter in objects of various thicknesses can be effectively inspected. Furthermore, by having the inspection unit inspect the object based on both the total transmission image and the transmission image, the presence or absence of foreign matter in the object can be accurately inspected.

[0050] In the above embodiment, the X-ray inspection apparatus includes a control unit that performs image processing. However, this is not limited to this. For example, the X-ray inspection apparatus does not necessarily have to include functions such as the image processing function in the control unit, the function of determining the presence or absence of a foreign object contained in an object based on a differential image, and the function of displaying the X-ray inspection results. Instead, these functions may be implemented in a control device that can communicate with the X-ray inspection apparatus via wire or wired communication. In this case, an X-ray inspection system can be realized that includes the X-ray inspection apparatus and the control device to which the inspection results of the X-ray inspection apparatus are input. This X-ray inspection system also achieves the same effects as those of the above embodiment. In addition, the configuration of the control unit included in the X-ray inspection apparatus can be simplified. Furthermore, the user can check the inspection results, etc., even when the user is located away from the X-ray inspection apparatus. The control device is not particularly limited, and may be, for example, a laptop PC or a tablet. Furthermore, the control device does not necessarily have to include the function of determining the presence or absence of a foreign object. [Explanation of symbols]

[0051] 1...X-ray inspection device, 3...support leg, 4...shielding box, 4a...feed-in entrance, 4b...feed-out exit, 5...transport unit, 6...X-ray irradiation unit, 7...X-ray detection unit, 8...display operation unit, 21...detection result acquisition unit, 22...image generation unit, 23...inspection unit, 24...judgment unit, 25...output unit, 26...storage unit, A...transport direction, G...item, P1...first transmission image, P2...second transmission image, P3...difference image.

Claims

1. an X-ray source that irradiates an article with X-rays in a plurality of energy bands; an X-ray detection unit capable of detecting the X-rays by a photon counting method; an image generating unit that generates a whole transmission image corresponding to all X-rays in the plurality of energy bands and a transmission image corresponding to a part of X-rays in the plurality of energy bands based on the detection result of the X-rays by the X-ray detection unit; an inspection unit that inspects the article based on the entire transmission image and the transmission image; An X-ray inspection device comprising:

2. The X-ray inspection apparatus according to claim 1 , wherein the entire transmission image is generated based on a part of information included in the detection result of the X-ray.

3. The X-ray inspection apparatus according to claim 1 , wherein the entire transmission image is generated based on all of the information included in the detection result of the X-ray.

4. Further comprising a display unit that accepts operations from the outside, 4. The X-ray inspection apparatus according to claim 1, wherein the display unit accepts a selection operation of an image to be used for inspection of the item by the inspection unit.

5. 5. The X-ray inspection apparatus according to claim 1, wherein the X-ray detection unit is a direct conversion type detection unit.

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