X-ray inspection device

Abstract

This X-ray inspection device is provided with: an X-ray irradiation unit that irradiates an article with X-rays; an X-ray detection unit that detects the X-rays; and an inspection unit that inspects the article on the basis of an image generated from the detection result of the X-rays detected by the X-ray detection unit. The inspection unit determines that the quality of the article is low when a quality index value calculated on the basis of the area of a region in which the article is present in the image and the shade of the image or the weight of the article is greater than a threshold value.

Description

Technical Field

[0001] The present disclosure relates to an X-ray inspection device. Background Art

[0002] An X-ray inspection device is known, comprising: an X-ray irradiation unit for irradiating an article with X-rays; an X-ray detection unit for detecting the X-rays; and an inspection unit for inspecting the article based on an X-ray transmission image generated based on the X-ray detection results. Japanese Patent No. 7393793, for example, discloses an X-ray inspection device that determines an article as defective when the range of pixels in an X-ray transmission image where the brightness is less than a first threshold and the range of pixels where the brightness is greater than a second threshold is greater than a predetermined range. Summary of the Invention

[0003] For example, items such as meat are sometimes treated as low-quality (hereinafter referred to as "low-quality items") if at least a portion of the meat is harder than acceptable. Therefore, X-ray inspection equipment such as those described above is required to not only detect foreign matter contaminated within the item but also accurately detect low-quality items. This demand has become particularly pronounced in recent years, as "woody breast," an unnatural hardening of chicken breast, has become a problem.

[0004] Therefore, an object of the present disclosure is to provide an X-ray inspection apparatus capable of detecting an article with degraded quality with high accuracy.

[0005] The inventors of the present disclosure have conducted repeated and in-depth research, resulting in the following insight: In an X-ray transmission image generated based on the detection results of X-rays transmitted through an article, the following differences may occur between qualified products and low-quality products that are at least partially harder than qualified products. In other words, qualified products are transported in a state of drooping and expanding due to their own weight, and tend to appear as light and large images in the X-ray transmission image. In contrast, the following insight was obtained: low-quality products are transported in a state of shrinking blocks due to their hardness, and tend to appear as dark and small images in the X-ray transmission image. Therefore, based on this insight, the inventors of the present disclosure discovered that low-quality products can be detected with high precision using an X-ray inspection device, and thus conceived of a method of the present disclosure.

[0006] (1) One embodiment of the present disclosure is an X-ray inspection device comprising: an X-ray irradiation unit for irradiating an article with X-rays; an X-ray detection unit for detecting the X-rays; and an inspection unit for inspecting the article based on an image generated based on a detection result of the X-rays detected by the X-ray detection unit, wherein the inspection unit determines that the quality of the article is low when a quality index value is greater than a threshold value, the quality index value being calculated based on the area of ​​a region in which the article exists in the image, the density of the image, or the weight of the article.

[0007] This X-ray inspection device utilizes the insight that qualified products tend to appear as light and large images in X-ray transmission images, while low-quality products that are harder than qualified products tend to appear as dark and small images in X-ray transmission images, thereby enabling high-precision detection of low-quality products.

[0008] (2) In the X-ray inspection apparatus described in (1) above, the inspection unit may calculate the quality index value by dividing the weight estimated based on the density of the region by the area of ​​the region. In this case, the above-mentioned knowledge can be effectively utilized to detect low-quality products with higher accuracy.

[0009] (3) In the X-ray inspection apparatus described in (1) above, the inspection unit may calculate the quality index value by dividing a weight estimated based on the density of a dense portion by the area of ​​the dense portion, where the density of the dense portion is higher than a fixed value. In this case, even low-quality products that partially include a portion harder than a qualified product can be inspected with high accuracy.

[0010] (4) The X-ray inspection apparatus described in (1) to (3) above may further include a detection unit that detects the height of the article, calculates the volume of the region based on the height of the article detected by the detection unit and the area of ​​the region, and calculates the quality index value based on the volume of the region and the density of the image or the weight of the article. In this case, the quality index value can be calculated taking into account the volume of the article, and low-quality products can be detected with higher accuracy.

[0011] (5) In the X-ray inspection apparatus of any one of (1) to (4) above, the article may include chicken breast, and the inspection unit may determine that the article includes lignified breast as being of low quality. In this case, higher quality chicken breast can be shipped.

[0012] According to the present disclosure, it is possible to provide an X-ray inspection apparatus capable of detecting an article with degraded quality with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing the configuration of an X-ray inspection apparatus according to one embodiment.

[0014] Figure 2 It shows Figure 1 The structural diagram of the interior of the shielding box.

[0015] Figure 3 It shows Figure 1 A block diagram of the functional structure of the control unit.

[0016] Figure 4A The diagram shows an example of an X-ray transmission image of a conforming product. Figure 4B FIG. 1 is a diagram showing an example of an X-ray transmission image related to a stock-out. DETAILED DESCRIPTION

[0017] Hereinafter, the embodiment will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals and redundant descriptions are omitted.

[0018] like Figure 1 As shown, the X-ray inspection apparatus 1 generates an X-ray transmission image of an article G while conveying it, and inspects the article G based on this X-ray transmission image. The article G before inspection is loaded into the X-ray inspection apparatus 1 via an inlet conveyor 51. The inspected article G is unloaded from the X-ray inspection apparatus 1 via an outlet conveyor 52. The article G is a product of a fixed size. The article G is not particularly limited and may include, for example, edible meat. In this embodiment, the article G may include chicken breast.

[0019] The X-ray inspection device 1 includes a device 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 and operation unit 8, and a control unit 10. The device body 2 houses the control unit 10 and the like. The support legs 3 support the device body 2. The shielding box 4 is provided on the device body 2. The shielding box 4 prevents X-rays (electromagnetic waves) from leaking to the outside. An inspection area R for inspecting an article G using X-rays is provided inside the shielding box 4. An inlet 4a and an outlet 4b are formed in the shielding box 4. The conveying unit 5 conveys the article G. In the example shown in the figure, the conveying unit 5 conveys the article G from the inlet 4a of the shielding box 4 via the inspection area R along a conveying direction A to the outlet 4b. The conveying unit 5 is, for example, a conveyor belt.

[0020] like Figure 1 as well as Figure 2 As shown, the X-ray irradiation unit 6 is an X-ray source that irradiates the article G conveyed by the conveyor unit 5 with X-rays. The X-ray irradiation unit 6 is disposed within the shielding box 4. The X-ray irradiation unit 6 includes, for example, an X-ray tube for emitting X-rays, and an aperture for expanding the X-rays emitted from the X-ray tube into a fan shape within a plane perpendicular to the conveying direction A. The X-rays irradiated by the X-ray irradiation unit 6 may include X-rays in various energy bands, ranging from low energy (long wavelength) to high energy (short wavelength).

[0021] The X-ray detection unit 7 is a sensor component that detects X-rays irradiated by the X-ray irradiation unit 6 and transmitted through the article G. The X-ray detection unit 7 may be a line sensor or a two-dimensionally arranged sensor group. The display operation unit 8 is provided on the device body 2. The display operation unit 8 displays various information and accepts external input of various conditions. The display operation unit 8 is, for example, a liquid crystal display that displays an operation screen as a touch panel. In this case, the operator can input various conditions via the display operation unit 8.

[0022] The control unit 10 controls the operation of various components of the X-ray inspection apparatus 1. The control unit 10 includes a processor such as a CPU (Central Processing Unit), memory such as ROM (Read Only Memory), RAM (Random Access Memory), and memory such as an SSD (Solid State Drive). The ROM stores a program for controlling the X-ray inspection apparatus 1. The control unit 10 constitutes the inspection unit that inspects an object based on an X-ray transmission image (image) generated based on the X-ray detection results of the X-ray detection unit 7.

[0023] like Figure 3 As shown, the control unit 10 includes an image generator 11, a quality index calculator 12, and a quality determiner 13. In the control unit 10, the image generator 11, the quality index calculator 12, and the quality determiner 13 are implemented as software. Alternatively, these components may be implemented as hardware. The image generator 11 generates an X-ray transmission image of the article G based on the detection results of the X-ray detector 7. The quality index calculator 12 calculates a quality index value, which serves as an indicator of the quality of the article G, based on the area of ​​the region containing the article G in the generated X-ray transmission image and the density of the X-ray transmission image.

[0024] For example, the quality index calculator 12 calculates the area of ​​the region containing the article G (hereinafter referred to as the "article region") in the X-ray transmission image by performing image processing (e.g., binarization at a predetermined percentage) on the X-ray transmission image. Furthermore, based on the property that heavier materials appear darker in X-ray transmission images, the quality index calculator 12 estimates the weight of each pixel in the article region of the X-ray transmission image based on the intensity of each pixel. The quality index calculator 12 then calculates the quality index value by dividing the weight of the article G by the area of ​​the article region.

[0025] If the calculated quality index value is greater than a threshold, the quality determination unit 13 determines that the quality of the item G is low. Specifically, if the calculated quality index value is greater than the threshold, the quality determination unit 13 determines that at least a portion of the item G, which is the subject of quality determination, is harder than a qualified item (a standard item). In this embodiment, the quality determination unit 13 determines that the item G is of low quality because it contains lignified breast meat (i.e., it determines that the item G is a low-quality item containing lignified breast meat).

[0026] The threshold value can be pre-set and stored in the control unit 10. The threshold value can also be set for each category of the object G. The threshold value can be a fixed value or a variable value that can be changed by the user via the display operation unit 8 or the like. Lignified breast is chicken breast that has not naturally hardened. Lignified breast is chicken breast that is as hard as wood. Lignified breast has a tough texture and is more likely to occur in larger chickens. Lignified breast is a fibrous (woody) chicken breast. Lignified breast is also called wood breast.

[0027] If the quality determination unit 13 determines that the article G is not of low quality, the control unit 10 causes the display operation unit 8 to display the generated X-ray transmission image 31 and a message indicating that the article G is OK (a message indicating that the article G is a qualified product) (see Figure 4A ). When the quality determination unit 13 determines that the quality of the article G is low, the control unit 10 causes the display operation unit 8 to display the generated X-ray transmission image 31 and a prompt message indicating that the article G is NG and out of stock (prompt message indicating that the article G is a low-quality article) (refer to Figure 4B ).

[0028] This study revealed that X-ray transmission images may show the following differences between conforming products and low-quality products, which are at least partially harder than conforming products. Specifically, conforming products, when transported in a state of drooping and expanding due to their own weight, tend to appear as light and large images in X-ray transmission images. In contrast, low-quality products, when transported in a state of shrinking blocks due to their hardness, tend to appear as dark and small images in X-ray transmission images.

[0029] Therefore, in the X-ray inspection apparatus 1, if the quality index value calculated by the control unit 10 based on the area of ​​the article region and the image density in the X-ray transmission image 31 is greater than a threshold value, the article G is determined to be of low quality. This allows for high-precision detection of low-quality products by leveraging the knowledge that conforming products tend to appear as light and large images in X-ray transmission images, while low-quality products that are harder than conforming products tend to appear as dark and small images.

[0030] In the X-ray inspection apparatus 1, the quality index calculation unit 12 of the control unit 10 calculates the quality index by dividing the weight estimated based on the shading of the article region by the area of ​​the article region. In this case, since the quality index corresponds to the weight of the article G per unit area of ​​the article region, the quality index value of low-quality products containing lignified breast meat increases because lignified breast meat is concentrated in a smaller area than that of qualified products. Therefore, in this case, the above-mentioned knowledge can be effectively utilized to detect these low-quality products with higher accuracy.

[0031] In the X-ray inspection apparatus 1, if the item G includes chicken breast, the control unit 10 determines that the item G includes lignified breast meat, indicating that the item G is of low quality. In this case, low-quality items including lignified breast meat can be identified and their shipment can be prevented. In other words, high-quality chicken breast meat can be shipped.

[0032] As mentioned above, although embodiment was described, one aspect of the present disclosure is not limited to the above-mentioned embodiment.

[0033] In the above embodiment, the weight of the article G may be measured by a weighing device separate from the X-ray inspection apparatus 1. In this case, the quality index value calculation unit 12 of the control unit 10 may calculate the quality index value based on the area of ​​the article region in the X-ray transmission image and the measured weight.

[0034] In the above-described embodiment, the quality index value calculation unit 12 of the control unit 10 can also calculate the quality index value by dividing the weight estimated based on the density of the dark portion (i.e., the portion of the object region in the X-ray transmission image where the density is higher than a predetermined value) by the area of ​​the dark portion. In this case, even low-quality products that partially include a harder portion than that of qualified products (e.g., lignified breast meat) can be inspected with high accuracy.

[0035] The above embodiment may further include a detection unit that detects the height of the articles G conveyed by the conveyor unit 5. In this case, the quality index value calculation unit 12 of the control unit 10 may calculate the volume of the articles G based on the height of the articles G detected by the detection unit and the area of ​​the article region, and calculate the quality index value based on the volume of the articles G and the density of the X-ray transmission image or the weight of the articles G. In this case, the quality index value corresponds to, for example, the weight per unit volume of the articles G. Therefore, the quality index value can be calculated taking into account the volume of the articles G, enabling the detection of low-quality products with higher accuracy.

[0036] In the above embodiment, when the calculated quality index value is less than the lower limit threshold (other threshold), the quality judgment unit 13 of the control unit 10 can also judge the item G as the quality judgment object as a low-quality product including an overly soft part, a loose interior, a large amount of fat, or a poor balance between red meat and fat.

[0037] In the above embodiment, the control unit 10 may also determine whether the quality of the article G is low through the following separate processing. Specifically, the control unit 10 may perform a first process and a second process. The first process uses the brightness of each pixel in the X-ray transmission image and a first threshold value for inspecting the article G for foreign matter to determine the presence or absence of foreign matter in the article G. The second process uses the brightness of each pixel in the X-ray transmission image and a second threshold value lower than the first threshold value for inspecting the quality of the article G to determine the quality of the article G. The second process determines that the quality of the article G is low if the range of pixels with brightness less than the first threshold value and greater than the second threshold value is greater than a predetermined range. Alternatively, the control unit 10 may binarize the X-ray transmission image based on the brightness less than the first threshold value and greater than the second threshold value, obtain the area of ​​a region in the binarized image, and determine that the quality of the article G is low if the area of ​​the region is greater than a predetermined area.

[0038] In this case, if the quality determination unit 13 determines that the quality of the item G is low and the aforementioned additional processing also determines that the quality of the item G is low, the item G may be determined to be highly likely to be a low-quality item (including lignified breast meat). Alternatively, if only either the quality determination unit 13 or the aforementioned additional processing determines that the quality of the item G is low, the item G may be determined to be highly likely to be a low-quality item. Alternatively, if neither the quality determination unit 13 nor the aforementioned additional processing determines that the quality of the item G is low, the item G may be determined to be a conforming item (with a low probability of being a low-quality item).

[0039] In each structure in the above embodiment and the above modification, it is not limited to the above-mentioned material and shape, and various materials and shapes can be applied. In addition, each structure in the above embodiment and the modification can be arbitrarily applied to each structure in other embodiments or modification.

Claims

1. An X-ray inspection device comprising: An X-ray irradiation unit irradiates an object with X-rays; An X-ray detection unit, detecting the X-rays; as well as an inspection unit that inspects the article based on an image generated based on a detection result of the X-rays detected by the X-ray detection unit, The inspection unit determines that the quality of the article is low when a quality index value is greater than a threshold value, the quality index value being calculated based on the area of ​​a region where the article exists in the image, the density of the image, or the weight of the article.

2. The X-ray inspection apparatus according to claim 1, wherein The inspection unit calculates the quality index value by dividing a weight estimated based on the shading of the region by an area of ​​the region.

3. The X-ray inspection apparatus according to claim 1, wherein The inspection unit calculates the quality index value by dividing a weight estimated from the density of a dark portion, which is a portion of the region having a density darker than a fixed value, by an area of ​​the dark portion.

4. The X-ray inspection apparatus according to claim 1 or 2, wherein: The X-ray inspection device further includes a detection unit configured to detect the height of the article. The inspection unit calculates the volume of the article based on the height of the article detected by the detection unit and the area of ​​the region. The inspection unit calculates the quality index value based on the volume of the article and the density of the image or the weight of the article.

5. The X-ray inspection apparatus according to claim 1 or 2, wherein: The items include chicken breast, The inspection unit determines that the quality of the item is low because the item includes lignified breast meat.

Images