JP7393793B2 - X-ray inspection equipment - Google Patents

Description

The present invention relates to an X-ray inspection device.

As a conventional X-ray inspection device, for example, the device described in Patent Document 1 is known. The X-ray inspection device described in Patent Document 1 includes an X-ray irradiation unit that irradiates an article with X-rays and an X-ray detection unit that detects the X-rays, and is created based on the X-ray detection results. Image processing is performed on the X-ray image to inspect the article.

International Publication No. 2006/001107

The X-ray inspection device performs an inspection for the presence or absence of foreign matter in an article, and determines whether the article is a good product or a defective product. An article is also considered defective if its quality is poor. For example, if a part of an article has different physical properties from other parts, such as when a part is harder than usual or too soft, the quality is poor and the product is considered defective. Conventionally, such defective products have been inspected by a worker directly touching the product to check the hardness of the product. Manual work by a worker may be influenced by the worker's experience and sense, and thus variations may occur.

One aspect of the present invention is to provide an X-ray inspection apparatus that can improve inspection accuracy.

An X-ray inspection apparatus according to one aspect of the present invention includes an X-ray irradiation section that irradiates an article with X-rays, an X-ray detection section that detects the X-rays, and a detection result of the X-rays detected by the X-ray detection section. an inspection unit that inspects the article based on the image created from the image, and the inspection unit detects foreign matter in the article using the brightness of each pixel of the image and a first threshold related to foreign matter inspection of the article. A second process of determining whether the quality of the article is good or bad using the brightness of each pixel of the image and a second threshold lower than the first threshold related to the quality inspection of the article. In the second process, if the range of pixels whose luminance is less than the first threshold and greater than or equal to the second threshold is greater than or equal to a predetermined range, the article is determined to be defective.

The inventors of the present application have found that when a defective part exists in an article, characteristics different from those of a foreign object appear in the X-ray detection results. Poor quality parts of articles do not appear as conspicuously in the detection results as foreign substances, but they have a certain range (area). Based on such knowledge, the inventors of the present application discovered a relationship between the brightness threshold and the range of each pixel of an image. Therefore, in the X-ray inspection apparatus according to one aspect of the present invention, the second process determines that the article is defective if the range of pixels whose luminance is less than the first threshold and greater than or equal to the second threshold is greater than or equal to a predetermined range. It is determined that Thereby, the X-ray inspection apparatus can perform not only foreign object inspection but also quality inspection of articles. Therefore, the X-ray inspection apparatus can improve inspection accuracy.

In one embodiment, the X-ray detection section includes a first detection section that detects X-rays in a first energy band that have passed through the article, and an X-ray that has passed through the article in a second energy band that is different from the first energy band. and a second detection section that detects the second detection section, and the inspection section may inspect the article based on an image created from the detection results of the first detection section and the second detection section. In articles, absorption of X-rays in two energy bands differs depending on physical properties. Therefore, in the X-ray inspection apparatus, by using images created from the detection results of two different energy bands, it becomes possible to more clearly capture foreign objects or quality defects. As a result, the X-ray inspection apparatus can further improve inspection accuracy.

In one embodiment, the inspection unit performs binarization processing on the image based on the luminance that is less than the first threshold value and greater than or equal to the second threshold value, obtains the area of the region in the binarized image, and obtains the area of the region in the binarized image. If the area of the item is greater than or equal to a predetermined area, it may be determined that the item is defective. With this configuration, it is possible to more accurately determine whether the quality of the article is good or bad.

According to one aspect of the present invention, inspection accuracy can be improved.

FIG. 1 is a configuration diagram of an X-ray inspection apparatus according to an embodiment. FIG. 2 is an internal configuration diagram of the shield box shown in FIG. 1. FIGS. 3(a) and 3(b) are diagrams showing transparent images. FIG. 4 is a diagram for explaining foreign matter inspection related to the first process. FIG. 5 is a diagram for explaining the quality inspection related to the second process.

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 equivalent elements are given the same reference numerals, and redundant description will be omitted.

As shown in FIG. 1, the X-ray inspection apparatus 1 includes an apparatus main body 2, support legs 3, a shield box 4, a transport section 5, an X-ray irradiation section 6, an X-ray detection section 7, and a display. It includes an operation section 8 and a control section (inspection section) 10. The X-ray inspection device 1 generates an X-ray transmission image of the article G while conveying the article G, and performs inspections of the article G (for example, storage quantity inspection, foreign object inspection, missing item inspection, etc.) based on the X-ray transmission image. (Crack/chip inspection, etc.). The article G to be inspected is carried into the X-ray inspection apparatus 1 by the carry-in conveyor 51. The inspected article G is carried out from the X-ray inspection apparatus 1 by the carry-out conveyor 52. Articles G determined to be defective by the X-ray inspection device 1 are sorted out of the production line by a sorting device (not shown) disposed downstream of the carry-out conveyor 52. Articles G determined to be non-defective by the X-ray inspection device 1 pass through the sorting device as they are. In this embodiment, the article G is meat.

The device main body 2 houses a control section 10 and the like. The support legs 3 support the device main body 2. The shield box 4 is provided in the device main body 2. The shield box 4 prevents leakage of X-rays (electromagnetic waves) to the outside. An inspection area R is provided inside the shield box 4 in which the article G is inspected using X-rays. The shield box 4 is formed with an entrance 4a and an exit 4b. The article G to be inspected is carried into the inspection area R from the carry-in conveyor 51 via the carry-in entrance 4a. The inspected articles G are carried out from the inspection area R to the carry-out conveyor 52 via the carry-out port 4b. An X-ray shielding curtain (not shown) is provided at each of the entrance 4a and the exit 4b to prevent leakage of X-rays.

The transport section 5 is arranged to penetrate through the center of the shield box 4. The conveyance unit 5 conveys the article G along the conveyance direction A from the carry-in port 4a through the inspection area R to the carry-out port 4b. The conveyance unit 5 is, for example, a belt conveyor stretched between an inlet 4a and an outlet 4b. Note that the conveying section 5, which is a belt conveyor, may protrude outward from the loading port 4a and the loading port 4b.

As shown in FIGS. 1 and 2, the X-ray irradiation unit 6 is arranged within the shield box 4. The X-ray irradiation unit 6 irradiates the article G transported by the transport unit 5 with X-rays. The X-ray irradiation section 6 includes, for example, an X-ray tube that emits X-rays, and an aperture section that spreads the X-rays emitted from the X-ray tube into a fan shape in a plane perpendicular to the transport direction A. . The X-rays emitted from the X-ray irradiator 6 include X-rays in various energy bands from low energy (long wavelength) to high energy (short wavelength). Note that "low" and "high" in the above-mentioned low energy band and high energy band indicate relatively "low" and "high" among the plurality of energy bands irradiated from the X-ray irradiation unit 6. It does not indicate a specific range.

The X-ray detection section 7 is arranged inside the shield box 4. The X-ray detection unit 7 detects X-rays in each of the plurality of energy bands that have passed through the article G. In this embodiment, the X-ray detection unit 7 is configured to detect X-rays in a low energy band (first energy band) and X-rays in a high energy band (second energy band). That is, the X-ray detection section 7 includes a first line sensor (first detection section) 11 and a second line sensor (second detection section) 12. The first line sensor 11 and the second line sensor 12 are each composed of X-ray detection elements arranged one-dimensionally along the horizontal direction perpendicular to the transport direction A. The first line sensor 11 detects low energy band X-rays that have passed through the article G and the conveyor belt of the conveyor section 5 . The second line sensor 12 detects high-energy band X-rays that have passed through the article G, the conveyor belt of the conveyor section 5, and the first line sensor 11.

As shown in FIG. 1, the display operation section 8 is provided in the device main body 2. The display operation unit 8 displays various information and accepts input of various conditions. 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 section 8.

The control unit 10 is arranged within the device main body 2. The control section 10 controls each section of the X-ray inspection apparatus 1 (in this embodiment, the transport section 5, the X-ray irradiation section 6, the X-ray detection section 7, the display operation section 8, and the The operation of the distributing device (not shown) arranged therein is controlled. Note that the sorting device is a device that removes inspected objects (articles) that are determined to be defective through image inspection by the X-ray inspection device 1 from the conveyance path. The control unit 10 includes a processor such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage such as an SSD (Solid State Drive). A program for controlling the X-ray inspection apparatus 1 is recorded in the ROM. The control unit 10 receives the detection results of low-energy band X-rays from the first line sensor 11 of the X-ray detection unit 7 and receives high-energy band X-rays from the second line sensor 12 of the Line detection results are input.

The control unit 10 generates a transparent image based on the detection results of the first line sensor 11 and the second line sensor 12. The control unit 10 generates a soft image (first transmission image) P10 based on the detection result of low energy band X-rays by the first line sensor 11. FIG. 3(a) is an example of a soft image P10 generated by the processing of the control unit 10. The soft image P10 has relatively high contrast and is dark overall. The control unit 10 generates a hard image (second transmitted image) P20 based on the detection result of high-energy band X-rays by the second line sensor 12. FIG. 3B is an example of a hard image P20 generated by the processing of the control unit 10. The hard image P20 has relatively low contrast and is bright overall.

The control unit 10 uses an image processing algorithm to process (image processing) the soft image P10 and the hard image P20 to generate a processed image. The image processing algorithm is a type of image processing procedure that is applied to the soft image P10 and the hard image P20. An image processing algorithm is configured by one image processing filter or a combination of multiple image processing filters. A plurality of image processing algorithms can be obtained from outside via a network such as the Internet. Further, the plurality of image processing algorithms can also be acquired from an external storage medium such as a USB memory or a removable hard disk. At least one of the plurality of image processing algorithms employs genetic algorithms (GA), which is a method that applies genetic and evolutionary mechanisms in the living world, and is based on the specifications of the X-ray inspection device 1 or It can be automatically generated from multiple image processing filters based on inspection conditions and the like. At least some of the plurality of image processing algorithms can also be appropriately set by the operator via the display operation section 8.

The control unit 10 determines whether the article G contains a foreign object F (see FIG. 4) by performing the first process. The control unit 10 determines the presence or absence of a foreign object F in the article G using the brightness of each pixel of the image and a first threshold value T1 (see FIG. 4) related to the foreign object inspection of the article G.

Specifically, the control unit 10 performs processing to match the size, brightness, position, etc. of the soft image P10 and the hard image P20, and adjusts the brightness value of the soft image P10 and the brightness value of the hard image P20 that have undergone the processing. By dividing by each pixel, a process is performed to extract the difference between the soft image P10 and the hard image P20. The control unit 10 generates a processed image by removing noise from the image from which the difference has been extracted, and binarizes the processed image using a certain value as a threshold to generate a binarized image (binarization). The control unit 10 generates a determination image P30 (see FIG. 4) by superimposing the binarized image and the hard image P20.

The control unit 10 determines whether or not the article G contains a foreign object F based on the determination image P30. As shown in FIG. 4, the control unit 10 determines that the foreign object F is included in the article G when the brightness value exceeds the first threshold T1 in the determination image P30. In this embodiment, the control unit 10 determines that one foreign object F is included in the article G in the first process. The control unit 10 causes the storage unit to store the first determination result obtained by the first process. Note that the first threshold value T1 is appropriately set according to the properties of the article G by a test or the like. Specifically, the first threshold T1 can be set using a sample mixed with foreign matter.

The control unit 10 determines whether the quality of the article G is good or bad by implementing the second process. In the present embodiment, the control unit 10 determines that the article G is a defective product when the article G includes a portion W (see FIG. 5) that is harder than other portions. The control unit 10 determines whether the quality of the article G is good or bad using the brightness of each pixel of the image and a second threshold T2 that is lower than the first threshold T1 related to the quality inspection of the article G. In the second process, the control unit 10 determines that the article G is defective if the range of pixels whose luminance is less than the first threshold T1 and equal to or greater than the second threshold T2 is equal to or greater than a predetermined range.

Specifically, the control unit 10 determines whether the quality of the article G is good or bad based on the determination image P30. As shown in FIG. 5, the control unit 10 determines that the article G is defective if the range of pixels whose luminance is less than the first threshold T1 and greater than or equal to the second threshold T2 is greater than or equal to a predetermined range in the determination image P30. It is determined that the product is of good quality. Specifically, the control unit 10 performs image binarization processing based on the luminance that is less than the first threshold T1 and greater than or equal to the second threshold T2, obtains the area of the region in the binarized image, and obtains the area of the region in the binarized image. If the area of the region is greater than or equal to the predetermined area, it is determined that the article G is defective. The control unit 10 acquires the area of the above region in the determination image P30 by image processing. The control unit 10 causes the storage unit to store the second determination result obtained by the second process. Note that the second threshold T2 and the predetermined area are appropriately set according to the properties of the article G through tests and the like. Specifically, the second threshold T2 and the predetermined area can be set using a sample having a hard portion W.

The control unit 10 executes the first process and the second process in parallel. If it is determined in the first process that the article G has a foreign object F, and/or if it is determined that the article G is defective in the second process, the control unit 10 sends a sorting signal to the sorting device. Output. Thereby, the sorting device sorts the articles G out of the production line. In addition, if the control unit 10 determines that there is a foreign object F in the article G in the first process, and/or if it determines that the article G is defective in the second process, the control unit 10 causes the display operation unit 8 to Display that fact. Specifically, when the control unit 10 determines that there is a foreign substance F in the article G, the control unit 10 causes the display operation unit 8 to display information notifying the presence of a foreign substance, and when it determines that the article G is defective. In this step, the display operation section 8 displays information notifying the defective product.

Next, the operation of the X-ray inspection apparatus 1 will be explained. Articles G to be inspected are carried into the inspection area R of the X-ray inspection apparatus 1 from the carry-in conveyor 51 via the carry-in entrance 4a (see FIG. 1). In the X-ray inspection apparatus 1, the X-ray irradiation section 6 irradiates the article G with X-rays, and the X-ray detection section 7 detects the X-rays of each of the plurality of energy bands that have passed through the article G. In this embodiment, the first line sensor 11 of the X-ray detection section 7 detects X-rays in a low energy band, and the second line sensor 12 of the X-ray detection section 7 detects X-rays in a high energy band ( (See Figure 2).

The control unit 10 generates a soft image P10 based on the detection results of low-energy band X-rays by the first line sensor 11, and generates a soft image P10 based on the detection results of high-energy band X-rays by the second line sensor 12. A hard image P20 is generated. Subsequently, the control unit 10 generates a determination image P30 from the generated soft image P10 and hard image P20.

The control unit 10 performs the first process based on the determination image P30. That is, the control unit 10 inspects the presence or absence of foreign matter F. Furthermore, the control unit 10 performs the second process based on the determination image P30. That is, the control unit 10 inspects for the presence or absence of defective products. The control unit 10 outputs a sorting signal to the sorting device when an NG determination (foreign substance contamination determination, defective product determination) is made in at least one of the first processing and the second processing. Further, the control unit 10 causes the display operation unit 8 to display the determination result of the NG determination.

The effects of the X-ray inspection apparatus 1 explained above will be explained. The inventors of the present application have found that when there is a portion of poor quality in the article G, characteristics different from those of the foreign object F appear in the X-ray detection results. A portion W that is harder than other portions of the article G does not appear as conspicuously in the detection results as the foreign matter F, but has a certain range (area). Based on such knowledge, the inventors of the present application discovered the relationship between the brightness threshold and the range. Therefore, in the X-ray inspection apparatus 1 according to the present embodiment, the control unit 10 controls whether the article G It is determined that the product is defective. Thereby, the X-ray inspection apparatus 1 can perform not only a foreign object inspection but also a quality inspection of the article G. Therefore, the X-ray inspection apparatus 1 can improve inspection accuracy.

In the X-ray inspection apparatus 1 according to the present embodiment, the X-ray detection unit 7 includes a first line sensor 11 that detects X-rays in the first energy band that have passed through the article G, and a first line sensor 11 that detects the X-rays in the first energy band that have passed through the article G. The second line sensor 12 detects X-rays in a second energy band different from the second line sensor 12. The control unit 10 inspects the article G based on an image created from the detection results of the first line sensor 11 and the second line sensor 12. In article G, absorption of X-rays in two energy bands differs depending on physical properties. Therefore, in the X-ray inspection apparatus 1, by using the soft image P10 and the hard image P20 created from the detection results of two different energy bands, it becomes possible to more clearly detect foreign substances or quality defects. As a result, the X-ray inspection apparatus 1 can further improve inspection accuracy.

In the X-ray inspection apparatus 1 according to the present embodiment, the control unit 10 binarizes the image based on the soft image P10 and the hard image P20 based on the luminance that is less than the first threshold T1 and greater than or equal to the second threshold T2. The process is performed to obtain the area of the region in the binarized image, and if the area of the region is greater than or equal to a predetermined area, it is determined that the article G is defective. With this configuration, it is possible to determine whether the quality of the article G is good or bad with higher accuracy.

Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various changes can be made without departing from the gist thereof.

In the embodiment described above, the X-ray detection section 7 includes the first line sensor 11 and the second line sensor 12 as an example. However, the X-ray detection section only needs to have at least one line sensor. In this case, the control unit 10 determines the foreign object F using two different image processing algorithms based on one transmitted image.

In the embodiment described above, the control unit 10 determines that the article G is defective if the article G includes a hard portion W (see FIG. 5) in the second process. However, in the second process, the control unit 10 may determine whether the quality of the article G is good or bad based on other factors. For example, the control unit 10 controls the control unit 10 when the product G includes a part that is too soft, when the content of the product G is sparse, or when the product G (meat) has a lot of fatty parts (the balance between lean meat and fatty meat is not good). It may be determined that the product G is of poor quality.

In the embodiment described above, the X-ray inspection apparatus 1 includes the transport section 5 as an example. However, the X-ray inspection apparatus does not need to include the transport section.

DESCRIPTION OF SYMBOLS 1... X-ray inspection device, 6... X-ray irradiation part, 7... X-ray detection part, 11... First line sensor (first detection part), 12... Second line sensor (second detection part), F... Foreign object , G...article, T1...first threshold value, T2...second threshold value.

Claims (3)

an X-ray irradiation unit that irradiates the article with X-rays;
an X-ray detection section that detects the X-rays;
an inspection section that inspects the article based on an image created from the detection results of the X-rays detected by the X-ray detection section;
The inspection department includes:
a first process of determining the presence or absence of foreign matter in the article using the brightness of each pixel of the image and a first threshold related to foreign matter inspection of the article;
performing a second process of determining whether the quality of the article is good or bad using the brightness of each pixel of the image and a second threshold lower than the first threshold related to quality inspection of the article;
The second process is an X-ray inspection in which the article is determined to be defective if the range of the pixels in which the luminance is less than the first threshold and greater than or equal to the second threshold is greater than or equal to a predetermined range. Device. The X-ray detection section is
a first detection unit that detects the X-rays in a first energy band that have passed through the article;
a second detection unit that detects the X-rays in a second energy band different from the first energy band that have passed through the article;
The X-ray inspection apparatus according to claim 1, wherein the inspection section inspects the article based on the image created from the detection results of the first detection section and the second detection section. The inspection unit performs binarization processing on the image based on the luminance that is less than the first threshold and greater than or equal to the second threshold, obtains the area of the region in the binarized image, and determines the area of the region. The X-ray inspection apparatus according to claim 1 or 2, wherein the article is determined to be defective if the area is greater than or equal to a predetermined area.

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