X-ray inspection equipment

Abstract

This invention relates to an X-ray inspection apparatus. The X-ray inspection apparatus includes: a transport unit for transporting an article; an irradiation unit for irradiating the article transported by the transport unit with X-rays; a sensor unit for detecting X-rays; an image generation unit for generating an inspection image including the article based on the X-ray detection result in the sensor unit; an inspection unit for inspecting whether the article contains foreign objects based on the inspection image; and a verification unit for generating a suspected defective image including virtual foreign objects by changing pixel values ​​that constitute a portion of the pixels of the inspection image, and verifying the reliability of the inspection based on the suspected defective image. The verification unit changes the pixel values ​​based on the attenuation rate of X-rays from a substance corresponding to the virtual foreign object.

Description

Technical Field

[0001] This invention relates to X-ray inspection apparatus. Background Technology

[0002] An X-ray inspection apparatus is known, comprising: a conveying unit for conveying an article; an irradiation unit for irradiating the article conveyed by the conveying unit with X-rays; a sensor for detecting X-rays that have passed through the article; and a control unit for generating an inspection image (X-ray transmission image) based on the X-rays detected by the sensor, and inspecting the article based on the inspection image (e.g., Japanese Patent Application Publication No. 2005-3481). Summary of the Invention

[0003] In production sites using X-ray inspection equipment like the one described above, test pieces are sometimes randomly introduced into the production line during normal operation to verify whether the X-ray inspection equipment can detect foreign objects and to test the reliability of the inspection. Preparing samples with test pieces attached and introducing them into the production line to verify the reliability of the inspection places a significant workload on the operators. Because the inspection is performed during production, there is also a risk that the test pieces may become foreign objects and be mixed into the finished product.

[0004] Therefore, in recent years, there has been an exploration of generating suspected defect images, including virtual foreign objects, and using these images to verify the reliability of inspections. However, for example, if a pre-captured image of the foreign object is used, or if a circular image uniformly filled with black is used as the virtual foreign object, it is sometimes impossible to accurately reproduce the test piece in the suspected defect image using the virtual foreign object.

[0005] The purpose of this invention is to provide an X-ray inspection device that can accurately reproduce test specimens in suspected defective images using virtual foreign objects.

[0006] (1) An X-ray inspection apparatus according to one aspect of the present invention includes: a conveying unit for conveying an article; an irradiation unit for irradiating the article conveyed by the conveying unit with X-rays; a sensor unit for detecting X-rays; an image generation unit for generating an inspection image including the article based on the detection result of X-rays in the sensor unit; an inspection unit for inspecting whether the article contains foreign objects based on the inspection image; and an inspection unit for generating a suspected defective image including virtual foreign objects by changing the pixel values ​​of a portion of the pixels constituting the inspection image, and for inspecting the reliability of the inspection based on the suspected defective image, wherein the inspection unit changes the pixel values ​​based on the attenuation rate of X-rays of the substance corresponding to the virtual foreign object.

[0007] In one aspect of the X-ray inspection apparatus of the present invention, the inspection unit generates a suspected defect image including a virtual foreign object by changing the pixel values ​​of a portion of the pixels constituting the inspection image. The inspection unit changes the pixel values ​​based on the attenuation rate of X-rays of the material corresponding to the virtual foreign object. Thus, in the suspected defect image, the virtual foreign object is depicted according to the attenuation rate of X-rays of the material. Therefore, compared to cases where, for example, an image of a pre-taken foreign object is used as the virtual foreign object, or a circular image uniformly filled with black is used as the virtual foreign object, the test piece can be reproduced with higher accuracy in the suspected defect image using the virtual foreign object.

[0008] (2) In (1) above, the inspection department may change the pixel value based on at least one of the X-ray transmission distance of the virtual foreign object, the density of the substance, and the mass absorption coefficient of the substance. In this case, since at least one of the transmission distance, the density of the substance, and the mass absorption coefficient of the substance is used in accordance with the type and shape of the substance specified as the virtual foreign object, the attenuation rate of the X-rays of the substance in the suspected defective image can be calculated with higher accuracy.

[0009] (3) In (2) above, the transmission distance may also be the length of the portion of the virtual straight line connecting the irradiation unit and the sensor unit that passes through the virtual foreign object. In this case, the transmission distance can be calculated geometrically.

[0010] (4) In any of (1) to (3) above, the sensor unit may have multiple detection elements arranged in a cross direction that is horizontally intersecting the transport direction of the transport unit, and the inspection unit may change the pixel value based on the attenuation rate of the X-rays calculated corresponding to each of the multiple detection elements. In this case, the virtual foreign object can be depicted at a resolution corresponding to the inspection image, and therefore, it is easier to reproduce the test piece with high precision using the virtual foreign object.

[0011] (5) In any of (1) to (4) above, the inspection unit may store information on multiple virtual foreign objects that are different in at least one of size, shape, and density, and change the pixel value based on the attenuation rate of the X-rays of the substance corresponding to the virtual foreign object selected from the multiple virtual foreign objects. In this case, a suspected defect image corresponding to any of the multiple pre-stored virtual foreign objects can be generated for inspection.

[0012] (6) In any of (1) to (5) above, the inspection department may determine that the reliability of the inspection is problematic when it obtains an inspection result that does not include foreign objects through inspection based on suspected defective images. In this case, it is possible to detect anomalies that should have been determined to include foreign objects but were determined not to include foreign objects.

[0013] (7) In any of (1) to (6) above, the inspection department may generate a suspected defective image and automatically perform inspection after a preset time has elapsed or after inspecting a preset number of items. In this case, the reliability of the inspection is automatically checked according to preset rules. This reduces the workload of the operator.

[0014] (8) In any of (1) to (7) above, the inspection department may generate a suspected defect image by extracting the shape of the item included in the inspection image and changing the pixel values ​​of a portion of the pixels on the inner side of the extracted shape. In this case, the suspected defect image generated by the inspection department becomes an image that is close to the inspection image obtained when foreign matter is mixed into the item produced on the production line. Therefore, the reliability of the inspection is verified based on the inspection image that is actually obtained when foreign matter is mixed into the item produced on the production line, thus improving the inspection accuracy.

[0015] (9) In any of (1) to (8) above, it is also possible that, during the execution of inspection, when the inspection department obtains an inspection result that does not include foreign objects based on an inspection image that does not include virtual foreign objects, it controls the sorting department to sort in a direction different from the direction in which normal items that do not include foreign objects are sorted during the non-execution of inspection; or, when the inspection department obtains an inspection result that does not include foreign objects based on an inspection performed on a suspected defective image during the execution of inspection, it stops the transport of items through the conveyor. In this case, it is possible to distinguish and sort normal items that are determined to be free of foreign objects during the execution of inspection from normal items during the non-execution of inspection. When it is determined that the inspection was not performed correctly, since the transport through the conveyor stops, it is possible to prevent items containing foreign objects from being processed as normal items after inspection.

[0016] According to several methods of the present invention, it is possible to reproduce the test piece with high precision using virtual foreign objects in suspected defective images. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the X-ray inspection apparatus involved in the implementation method.

[0018] Figure 2 yes Figure 1 The diagram shows the internal structure of the shielding box.

[0019] Figure 3 It means Figure 1 A block diagram of the functional structure of an X-ray inspection device.

[0020] Figure 4 This is a schematic diagram illustrating the general outline of a method for generating potentially defective images.

[0021] Figure 5A This is a schematic diagram illustrating multiple detection elements arranged along intersecting directions.

[0022] Figure 5B It is Figure 5A A magnified schematic diagram showing multiple detection elements.

[0023] Figure 6 This is a schematic diagram illustrating an example of calculating the transmission distance of X-rays.

[0024] Figure 7 This is a schematic diagram illustrating the change of pixel values ​​based on the attenuation rate of X-rays from a substance corresponding to a virtual foreign object.

[0025] Figure 8 This is a flowchart illustrating the operation of an X-ray inspection device.

[0026] Figure 9 This is a flowchart illustrating the intermediate inspection process of an X-ray inspection device.

[0027] Figure 10A It is a diagram used to illustrate the problem points of existing examples.

[0028] Figure 10B It is a diagram used to illustrate the problem points of existing examples.

[0029] Figure 11 It is a diagram used to illustrate the problem points of existing examples.

[0030] Explanation of reference numerals in the attached figures

[0031] 1...X-ray inspection device; 5...Conveyor belt (conveying section); 6...X-ray irradiation section (irradiation section); 7...X-ray detection section (sensor section); 7a, 7b, 7p...Detection element; 10A...Storage section (inspection section); 15...Sorting device (sorting section); D1...Conveying direction; D2...Crossing direction; G...Item; VI, VIM...Suspected defective images. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the description of the drawings, the same or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted.

[0033] like Figures 1-3As shown, the X-ray inspection apparatus 1 includes: a main body 2, support legs 3, a shielding box 4, a conveyor belt 5 (conveyor section), an X-ray irradiation section 6 (irradiation section), an X-ray detection section 7 (sensor section), a display 8, a controller 10 (image generation section, inspection section, testing section), and a storage section 10A (testing section). The X-ray inspection apparatus 1 transports an article G while acquiring an inspection image IM of the article G, and performs foreign object contamination inspection on the article G based on the inspection image IM.

[0034] Before inspection, the item G is moved into the X-ray inspection device 1 via the infeed conveyor 9A, and after inspection, the item G is moved out of the X-ray inspection device 1 via the outfeed conveyor 9B. In the normal (in-production) foreign object inspection, which is not an intermediate inspection (inspection) described later, the item G determined to be defective by the X-ray inspection device 1 is sorted out of the production line (outside the system) by the sorting device (sorting section) 15 located downstream of the outfeed conveyor 9B, while the item G determined to be good by the X-ray inspection device 1 passes directly through the sorting device 15.

[0035] The shielded box 4 has a loading inlet 4a and a loading outlet 4b. Before inspection, the item G is loaded into the shielded box 4 from the loading inlet conveyor 9A via the loading inlet 4a. After inspection, the item G is loaded out of the shielded box 4 via the loading outlet 4b onto the loading outlet conveyor 9B. The detection sensor 13 detects the item G being transported by the loading inlet conveyor 9A.

[0036] The conveyor belt 5 is disposed inside the shielding box 4, and transports the item G from the inlet 4a to the outlet 4b along the conveying direction D1. The X-ray irradiation unit 6 is disposed inside the shielding box 4, and irradiates the item G transported by the conveyor belt 5 with X-rays.

[0037] The X-ray detection unit 7 is disposed within the shielding box 4 and detects X-rays irradiated by the X-ray irradiation unit 6 that have passed through the article G and the conveyor belt 5. The X-ray detection unit 7 has multiple detection elements 7p arranged in a cross direction D2 that horizontally intersects the conveyor belt 5's transport direction D1. The X-ray detection unit 7 is configured, for example, as a line sensor, which includes multiple photodiodes arranged one-dimensionally in a horizontal direction perpendicular to the transport direction D1, and scintillators disposed opposite each photodiode on the X-ray incident side. The electrical signals detected by the X-ray detection unit 7 are acquired by the controller 10.

[0038] A display 8 is installed on the main body 2 of the device. The display 8 has a display screen as a touch panel and a speaker. The display 8 functions as an operation input unit for accepting various input conditions via the display screen. The display 8 also functions as a display unit for displaying the inspection results of the X-ray inspection device 1 via the display screen.

[0039] The controller 10 is disposed in the main body 2 of the device and controls the operation of various parts of the X-ray inspection device 1. The controller 10 includes a processor such as a CPU, a memory such as ROM and RAM, and a storage device such as an SSD. The controller 10 may also be configured as hardware formed by electronic circuits. The storage unit 10A is composed of one or more of HDD and flash memory. The storage unit 10A may be disposed within the main body 2 of the device or may be configured to communicate with the controller 10 via a network.

[0040] The controller 10 generates an inspection image of the item G based on the detection results of X-rays in the X-ray detection unit 7. The inspection image is an image with pixel values ​​that correspond to the intensity of the X-rays that have passed through the item G.

[0041] The controller 10 generates a suspected defective image, including a virtual foreign object, by changing the pixel values ​​of a portion of the pixels constituting the inspected image, and verifies the reliability of the inspection based on the suspected defective image. In a production site using the X-ray inspection apparatus 1, during the normal operation of the X-ray inspection apparatus 1 used to inspect article G during production, intermediate checks are performed to verify the reliability of the inspection, such as at predetermined intervals, to confirm whether the target foreign object can be detected normally in the X-ray inspection apparatus 1. The controller 10 generates a suspected defective image including a virtual foreign object, and automatically verifies the reliability of the inspection based on the suspected defective image, for example, at predetermined intervals during normal operation of the X-ray inspection apparatus 1.

[0042] exist Figure 10A The diagram shows an acrylic component AC with actual foreign objects F1 and F2 attached to its upper surface. The acrylic component AC has a portion AC1 with a thickness TH1 and a portion AC2 with a thickness TH2 greater than TH1. Foreign objects F1 and F2 are, for example, stainless steel spheres, with the diameter of foreign object F2 being larger than the diameter of foreign object F1. Two foreign objects F1 are attached to portions AC1 and AC2, respectively. One foreign object F2 is attached to the boundary between portions AC1 and AC2. Figure 10B Showing from Figure 10A The diagram above shows the X-ray transmission results when an acrylic component AC with foreign objects F1 and F2 attached is irradiated with X-rays. (See diagram above.) Figure 10B As shown, the brightness of transmitted X-rays differs in portions AC1 and AC2. The brightness XAC2 corresponding to portion AC2 is lower than the brightness XAC1 corresponding to portion AC1. In brightness XF1 and brightness XF3, even foreign objects F1 of the same diameter exhibit different brightness waveforms. Here, if using... Figure 10B The circular image shown, uniformly filled with black, has the problem of failing to reproduce the waveform of brightness differences when X-rays are transmitted through it, even for the same foreign object. For example, as... Figure 11As shown, if a circular image uniformly covered in black is pasted as a virtual foreign object at two locations with different thicknesses of the object, it will not be able to fully reproduce the situation where the brightness of the X-rays should be different at the two locations.

[0043] Therefore, in this embodiment, the controller 10 changes the pixel values ​​that constitute a portion of the pixels in the inspection image IM generated during the inspection of the item G, based on the attenuation rate of the X-rays of the substance corresponding to the virtual foreign object. As an example, the controller 10 changes the pixel values ​​based on the attenuation rate of the X-rays calculated corresponding to each of the plurality of detection elements 7a, 7b, etc. of the X-ray detection unit 7.

[0044] Figure 4 This is a schematic diagram illustrating a general outline of a method for generating potentially defective images. Figure 4 In the example, the virtual foreign object IF is a stainless steel sphere with a predetermined diameter. The controller 10 assumes that the virtual foreign object IF is virtually irradiated with X-rays and estimates the brightness of the virtually transmitted X-rays. The controller 10 estimates the brightness of the virtually transmitted X-rays, for example, by assuming, at the location of the virtual foreign object IF, that an actual foreign object of the same shape and material as the virtual foreign object IF exists. Figure 5A and Figure 5B As shown, it can be assumed that if a virtual foreign object IF is virtually irradiated with X-rays, the X-rays that have passed through the foreign object IF will reach the multiple detection elements 7p of the X-ray detection unit 7. It can be assumed that such a virtual X-ray transmission path XP exists for each of the multiple detection elements 7p.

[0045] Figure 4 This image shows a portion of an inspection image IM including the article G, generated based on the detection results from the X-ray detection unit 7 that transmits X-rays through the article G. The inspection image IM includes pixels Px1 and Px2 corresponding to the plurality of detection elements 7a and 7b of the X-ray detection unit 7. Figure 4 In this diagram, for ease of explanation, the pixel values ​​A and B of pixels Px1 and Px2 are visually represented by the varying shades of the mesh within the area surrounded by thick lines. Figure 4 In the example, the pixel values ​​A and B of pixels Px1 and Px2 are pixel values ​​that are not affected by the virtual foreign object IF. For Figure 4 The image IM includes the inspection image of item G. For example, if a virtual foreign object IF is further configured along the path of the X-rays passing through item G, then it serves as... Figure 5A and Figure 5BSuch a transmission path XP can be envisioned as transmission paths XPa and XPb. Here, transmission paths XPa and XPb refer to the paths of X-rays that pass through the virtual foreign object IF and the object G, respectively, and reach pixels Px1 and Px2. It can be envisioned that each of the X-ray paths such as transmission paths XPa and XPb corresponds to a detection element 7p within a range corresponding to the location where the virtual foreign object IF is located. For each of the virtual transmission paths XPa and XPb corresponding to the plurality of detection elements 7a, 7b, etc. of the X-ray detection unit 7, the controller 10 calculates the attenuation rate of the X-rays that virtually pass through the virtual foreign object IF, and changes the pixel value based on the attenuation rate of the X-rays.

[0046] The controller 10 can also change the pixel value based on the X-ray transmission distance in the virtual foreign object IF, the density of the material corresponding to the virtual foreign object IF, and the mass absorption coefficient of the material corresponding to the virtual foreign object IF. The transmission distance can be the length of the portion of the virtual straight line connecting the X-ray irradiation unit 6 and the X-ray detection unit 7 that passes through the virtual foreign object IF. For example, as... Figure 6 As shown, the transmission distance can also be the length L of the transmission path XP. When the virtual foreign object IF is spherical, the length L can be geometrically calculated based on the radius R of the virtual foreign object IF and the offset SFT. The offset SFT is the separation distance of the transmission path XP relative to the center M of the virtual foreign object IF along the intersection direction D2. The position of the center M of the virtual foreign object IF can also be a coordinate value determined by the setting of where the virtual foreign object IF is positioned in the inspection image IM. The position of the transmission path XP can be a coordinate value determined by the position of the detection element 7p, which is the object of pixel value change (estimation). The tilt of the transmission path XP relative to the X-ray detection unit 7 shown in Figure 5 can be considered or ignored. Without considering this tilt, in... Figure 6 In this context, the arrow of the offset SFT can also be considered to be orthogonal to the arrow of the path XP.

[0047] The density of the material corresponding to the virtual foreign object IF and the mass absorption coefficient of the material corresponding to the virtual foreign object IF are examples of object characteristics used to calculate the attenuation rate of X-rays. To calculate the attenuation rate of X-rays, only one of these characteristics may be used, or other object characteristics may be used. The object characteristics used to calculate the attenuation rate of X-rays may also be stored, for example, as parameters in the storage unit 10A. The material corresponding to the virtual foreign object IF is, for example, stainless steel. There is no particular limitation on the material corresponding to the virtual foreign object IF; it can be selected according to the purpose of the intermediate inspection.

[0048] like Figure 7As shown, the controller 10 calculates the attenuation rate of X-rays for each of the plurality of detection elements 7p, for example, by multiplying the transmission distances L1 and L2 of X-rays in the virtual foreign object IF, the density of the material corresponding to the virtual foreign object IF, and the mass absorption coefficient of the material corresponding to the virtual foreign object IF. The controller 10 multiplies the calculated attenuation rate of X-rays by, for example, Figure 4 The pixel values ​​A and B of pixels Px1 and Px2 are used to calculate pixel values ​​α and β. Pixel values ​​α and β are the pixel values ​​of pixels Pxv1 and Pxv2 that constitute the suspected defective image VIM. Pixels Pxv1 and Pxv2 are pixels in the suspected defective image VIM corresponding to pixels Px1 and Px2. Pixel values ​​α and β are pixel values ​​that simulate the further attenuation of X-rays transmitted through object G due to the virtual foreign object IF. Controller 10 generates the suspected defective image VIM composed of pixels Pxv1 and Pxv2 by changing the pixel values ​​of pixels Px1 and Px2 to pixel values ​​α and β.

[0049] It is worth mentioning that the controller 10 can also generate a suspected defective image VIM by extracting the shape of the item G included in the inspection image IM and changing the pixel values ​​of a portion of the pixels on the inner side of the extracted shape of the item G (the dark area with the shape of the item G as the edge, equivalent to the inspection object). The controller 10 acquires the inspection image IM of the item G sent from the upstream side and extracts the shape of the item G. The shape of the item G can be extracted using known methods such as binarization, sharpening, and pattern matching.

[0050] It should be noted that the virtual foreign object (IF) is not limited to the case of an attached or mixed-in item G; it can also be attached to the container containing the item G where the item G is not present. In this case, instead of the pixel values ​​A and B of pixels Px1 and Px2, pixel values ​​corresponding to the brightness of X-rays that pass through the container but not through the item G can be used. The controller 10 can also generate a suspected defective image (VIM) by changing the pixel values ​​of a portion of the outer edge of the extracted item G (the bright part with the shape of the item G as the edge, equivalent to the inspection object), a portion of the pixels on the boundary line of the extracted item G (the weak edge), a portion of the pixels on the outer edge of the extracted container containing the item G (the bright part with the shape of the container as the edge, equivalent to outside the inspection object), and a portion of the pixels on the boundary line of the extracted container containing the item G (the strong edge).

[0051] Regarding the location of the virtual foreign object IF in the inspection image IM from the above configuration example, considering the position that affects inspection performance, it can be selected according to the operator's input operation, randomly selected by the controller 10, or a configuration mode can be preset in the controller 10. Alternatively, the coordinates in the inspection image IM can be directly specified by the operator's input operation, thereby configuring the virtual foreign object IF in the inspection image IM. The operator's input operation is not particularly limited; it can be an operation of touching or clicking the desired position in the inspection image IM displayed on the display 8, or an operation of inputting coordinate values. By configuring the virtual foreign object IF in this way, the reproducibility of the virtual foreign object IF's position is improved compared to the case of manually pasting the test piece. As a result, even in the inspection of items G where sensitivity differences arise due to the position of the test piece making foreign object detection more difficult, sensitivity differences (inconsistencies) can be reduced, and the quantification of sensitivity evaluation at specific locations can be easily achieved.

[0052] The storage unit 10A can also store multiple virtual foreign object IFs that differ in at least one of size, shape, and density. The controller 10 can also change the pixel value based on the X-ray attenuation rate of the material corresponding to the virtual foreign object IF selected from the multiple virtual foreign object IFs. For example, the controller 10 can select the type of virtual foreign object IF for intermediate inspection from the multiple virtual foreign object IFs stored in the storage unit 10A according to operator input or a preset intermediate inspection mode. When the selection of the type of virtual foreign object IF is automatic according to a preset intermediate inspection mode, it is easier to quantify the detection accuracy of foreign objects for a specific inspection image IM according to each type of virtual foreign object IF compared to manually pasting test pieces.

[0053] The controller 10 verifies the reliability of the inspection based on the suspected defective image VIM generated as described above. "Verification reliability" here refers to, for example, confirming whether foreign objects identified from one or more elements determined by factors such as size, thickness, and material can be detected. The elements to be verified (in other words, the required performance) are configured to be set via the display 8. Based on the suspected defective image VIM, the controller 10 determines whether the predetermined required performance is met.

[0054] The controller 10 generates a suspected defective image VIM and automatically performs inspection after a preset time (e.g., 1 hour) has elapsed since the start of production of item G (from the start of inspection) or after a preset number of items G (e.g., 1000) have been inspected. In other words, the controller 10 performs routine inspections based on the inspection image IM to check whether item G contains foreign objects, from the start of production of item G until the preset time (e.g., 1 hour) has elapsed or until a preset number of items G (e.g., 1000) have passed through the X-ray inspection device 1. The controller 10 generates the suspected defective image VIM for the first time when the preset time has elapsed since the start of production of item G or when a preset number of items G have passed through the X-ray inspection device 1.

[0055] If the controller 10 obtains an inspection result that does not include foreign objects through inspection based on a suspected defective image VIM, it determines that the reliability of the inspection is problematic. If the controller 10 obtains an inspection result that includes foreign objects through inspection based on a suspected defective image VIM, it determines that the reliability of the inspection is not problematic. In this way, the controller 10 uses a suspected defective image VIM to verify the reliability of the inspection.

[0056] The controller 10 controls the sorting of the sorting device 15 located downstream of the X-ray inspection device 1. If the controller 10 determines that the item G is normal (excluding foreign objects) during the routine inspection, it does not operate the sorting device 15 and transports the item G, conveyed by the outgoing conveyor belt 9B, downstream. If the controller 10 determines that the item G is abnormal (including foreign objects) during the routine inspection, it operates the sorting device 15 and sorts the item G outside the production line (in a direction different from its direction of transport in the conveyor section). Examples of the sorting device 15 include arm-type sorting devices using arms, lifting conveyor belt-type sorting devices, pusher-type sorting devices using pushers, drop-plate sorting devices, jet-type sorting devices, and fin-type sorting devices.

[0057] When the controller 10 obtains an inspection result excluding foreign objects during the reliability check based on the suspected defective image VIM, in other words, when it determines that there is a problem with the reliability of the inspection, it stops the transport of item G via the infeed conveyor 9A, the transport conveyor 5, and the outfeed conveyor 9B. That is, in this case, the controller 10 determines that the current inspection performed by the X-ray inspection device 1 does not meet the predetermined performance requirements, and thus stops the operation of the production line. The controller 10 may also notify the operator, for example, by displaying the problem with the reliability check result on the display 8.

[0058] Next, the operation of the X-ray inspection device 1 will be explained. For example... Figure 8As shown, if production of item G begins (step S1), the controller 10 resets the counter that counts the number of inspections (step S2). The controller 10 counts the items G transported to the X-ray inspection apparatus 1 (step S3). The controller 10 counts the items G based on the detection results of the detection sensor 13 that detects the items G moving on the conveyor belt 9A. The X-ray inspection apparatus 1 acquires an inspection image (X-ray transmission image) IM of the transported items G (step S4). The controller 10 confirms the number of inspections when the inspection image IM is acquired (step S5).

[0059] If the controller 10 confirms that the number of checks i is less than a predetermined number N (e.g., N=1000), it performs a routine check based on the inspection image IM to check whether the item G contains foreign objects (step S6). Here, if the controller 10 determines that the item G contains foreign objects based on the routine check based on the inspection image IM (step S6: Yes), it activates the sorting device 15 (step S7) to discharge the item G out of the system. If the controller 10 determines that the item G does not contain foreign objects based on the routine check based on the inspection image IM (step S6: No), it does not activate the sorting device 15, but instead transports the item G to the downstream side of the outgoing conveyor belt 9B.

[0060] Next, controller 10 determines whether the production of item G has ended (step S8). If it determines that the production of item G has ended (step S8: Yes), it terminates a series of processes. Thus, the series of processes in X-ray inspection device 1 ends. Furthermore, the termination of production of item G is determined, for example, based on whether the number of items G produced in one day has been reached. If controller 10 determines that the production of item G has not ended (step S8: No), it returns to step S3 and increments the inspection count i by one. Afterward, controller 10 executes the steps from step S4 onward.

[0061] If controller 10 confirms that the number of checks i is greater than or equal to a predetermined number N (e.g., N=1000), it performs an intermediate check (step S9). As an intermediate check, such as... Figure 9 As shown, the controller 10 manually or automatically selects the type of the virtual foreign object IF (step S10) and manually or automatically sets the configuration of the virtual foreign object IF (step S11). As described above, the controller 10 calculates the attenuation rate of X-rays of the material corresponding to the virtual foreign object IF (step S12) and generates a suspected defective image VIM by changing the pixel value based on the attenuation rate of X-rays (step S13).

[0062] If the inspection is not based on an inspection image that does not include virtual foreign objects, the controller 10 performs a reliability check on the inspection using the suspected defective image VIM (step S14: No). If the controller 10 determines that the inspection using the suspected defective image VIM does not include foreign objects (step S15: Yes), it determines that there is a problem with the reliability of the inspection (step S16) and stops the transport of the item G via the inbound conveyor 9A, the transport conveyor 5, and the outbound conveyor 9B (step S17). Thus, the intermediate inspection process ends.

[0063] On the other hand, when the controller 10 determines that the inspection using the suspected defective image VIM contains foreign objects (step S15: no), it determines that the reliability of the inspection is not a problem (step S18), and then operates the sorting device 15 to discharge the item G out of the system (step S19).

[0064] On the other hand, when the inspection is based on an inspection image that does not include virtual foreign objects, the controller 10 can perform an inspection without using the suspected defective image VIM (step S14: Yes). If the controller 10 determines that no foreign object is present during the inspection without using the suspected defective image VIM (step S20: Yes), it activates the sorting device 15 to sort the item as a normal item in the inspection in a direction different from steps S19 and S22 (step S21). On the other hand, if the controller 10 determines that a foreign object is present during the inspection without using the suspected defective image VIM (step S20: No), it activates the sorting device 15 to discharge the item G out of the system (step S22). This ends the intermediate inspection process. Afterwards, the controller 10 returns to... Figure 8 In the above step S8, a determination is made as to whether the production of item G has ended.

[0065] As explained above, in the X-ray inspection apparatus 1, the controller 10 generates a suspected defective image VIM including a virtual foreign object IF by changing the pixel values ​​that constitute a portion of the pixels of the inspection image. The controller 10 changes the pixel values ​​based on the attenuation rate of X-rays of the material corresponding to the virtual foreign object IF. Thus, the virtual foreign object IF is depicted in the suspected defective image VIM according to the attenuation rate of X-rays of the material. Therefore, compared to cases where, for example, a pre-captured foreign object image is used as the virtual foreign object IF or a circular image uniformly filled with black is used as the virtual foreign object IF, the test piece can be reproduced in the suspected defective image VIM with higher accuracy using the virtual foreign object IF.

[0066] The controller 10 modifies the pixel value based on at least one of the X-ray transmission distance L in the virtual foreign object IF, the density of the material, and the mass absorption coefficient of the material. Therefore, by using at least one of the transmission distance, material density, and mass absorption coefficient corresponding to the type and shape of the material designated as the virtual foreign object IF, the attenuation rate of X-rays in the suspected defective image VIM can be calculated with higher accuracy.

[0067] The transmission distance L is the length of the portion of the virtual straight line connecting the X-ray irradiation unit 6 and the X-ray detection unit 7 that passes through the virtual foreign object IF. The transmission distance L can be calculated geometrically.

[0068] The X-ray inspection unit 7 has multiple inspection elements 7p arranged along a cross direction D2 that intersects the conveyor belt 5 in the horizontal direction D1. The controller 10 changes the pixel values ​​based on the attenuation rate of the X-rays calculated corresponding to each of the multiple inspection elements 7p. As a result, a virtual foreign object IF can be depicted at a resolution corresponding to the inspection image, making it easier to reproduce the test piece with high accuracy using the virtual foreign object IF.

[0069] The storage unit 10A stores information on multiple virtual foreign object IFs that differ in at least one of size, shape, and density. The controller 10 modifies pixel values ​​based on the attenuation rate of X-rays of the material corresponding to the virtual foreign object IF selected from the multiple virtual foreign object IFs. This allows for the generation of a suspected defect image (VIM) corresponding to any of the pre-stored multiple virtual foreign object IFs for inspection.

[0070] When the controller 10 obtains an inspection result that does not include foreign objects through inspection based on a suspected defective image (VIM), it determines that there is a problem with the reliability of the inspection. Therefore, it is possible to detect anomalies that should have been classified as including foreign objects but were instead classified as not including them.

[0071] The controller 10 generates a suspected defective image (VIM) after a preset time has elapsed or after inspecting a preset number of items G, and automatically performs an inspection. Based on this, the reliability of the inspection is automatically verified according to preset rules. This reduces the workload of the operator.

[0072] The controller 10 generates a suspected defective image VIM by extracting the shape of the item G included in the inspection image and changing the pixel values ​​of a portion of the pixels inside the extracted shape. Thus, the suspected defective image VIM generated by the controller 10 becomes an image close to the inspection image IM obtained when foreign matter is mixed into the item G produced on the production line. Therefore, by verifying the reliability of the inspection based on the inspection image IM actually obtained when foreign matter is mixed into the item G produced on the production line, the inspection accuracy can be improved.

[0073] When the controller 10 obtains an inspection result excluding foreign objects based on an inspection image excluding virtual foreign objects (IF) during intermediate inspection, it controls the sorting device 15 to sort the items G in a direction different from the direction in which normal items G excluding foreign objects are sorted during non-intermediate inspection. When the controller 10 obtains an inspection result excluding foreign objects based on a suspected defective image (VIM) during intermediate inspection, it stops the transport of items G via the infeed conveyor 9A, conveyor 5, and outfeed conveyor 9B. This allows for the differentiation and sorting of normal items determined to be free of foreign objects during intermediate inspection from normal items during non-intermediate inspection (normal operation). When an inspection is determined to be incorrect, the stopping of transport via the infeed conveyor 9A, conveyor 5, and outfeed conveyor 9B prevents items G containing foreign objects from being processed as normal items after intermediate inspection.

[0074] The above describes the embodiments of the present invention, but the present invention is not necessarily limited to the above embodiments and various modifications can be made without departing from its spirit.

[0075] In the above embodiment, the controller 10 uses all of the X-ray transmission distance in the virtual foreign object IF, the density of the substance corresponding to the virtual foreign object IF, and the mass absorption coefficient of the substance corresponding to the virtual foreign object IF, but is not limited to this example, and may also change the pixel value based on at least one of these.

[0076] In the above embodiment, the transmission distance L is the length of the portion of the virtual straight line connecting the X-ray irradiation unit 6 and the X-ray detection unit 7 that passes through the virtual foreign object IF, but it is not limited to this example. The transmission distance can also be given using predetermined parameters corresponding to the virtual foreign object.

[0077] In the X-ray inspection apparatus 1 described in the above embodiments and variations, an X-ray detection unit 7 consisting of a single line sensor was used as an example. However, it can also be configured as a multi-energy sensor consisting of a first line sensor and a second line sensor that can detect different energy bands. The X-ray detection unit 7 can also detect X-rays by photon counting. The X-ray detection unit 7 can be either a direct conversion type detection unit or an indirect conversion type detection unit. These sensors are arranged, for example, at least in a direction orthogonal to the conveying direction and the vertical direction of the conveyor belt 5 (width direction). This element can be arranged not only along the width direction but also along the conveying direction.

[0078] In the above embodiment, the storage unit 10A stores information of multiple virtual foreign object IFs, but it is not limited to this example and may also store information of a single virtual foreign object IF.

[0079] In the above embodiment, an inspection based on an inspection image excluding virtual foreign object IFs was performed during the intermediate inspection, but this inspection can be omitted. Figure 9 S20~S22.

[0080] In the description of the operation of the X-ray inspection apparatus 1 in the above embodiment, examples are listed as follows: Figure 4 The example shown illustrates how controller 10 determines the reliability of performing a check based on the number of checks, but it is not limited to this. For example, controller 10 may also determine the reliability of performing a check based on the elapsed time (e.g., 1 hour) since the start of the check.

[0081] In the above embodiment, examples of the controller 10 generating a suspected defective image VIM and automatically performing an inspection reliability test when a preset time has elapsed since the start of production of item G or when a preset number of items G have been inspected are given. However, the reliability test of the inspection can also be performed according to instructions from the operator.

Claims

1. An X-ray inspection device, comprising: The transport department transports goods. An irradiation unit irradiates the article conveyed by the transport unit with X-rays; The sensor unit detects the X-rays; The image generation unit generates an inspection image including the item based on the detection result of the X-rays in the sensor unit; The inspection department checks whether the article contains foreign objects based on the inspection images; and The inspection department generates a suspected defective image, including a virtual foreign object, by changing the pixel values ​​of a portion of the pixels constituting the inspected image, and verifies the reliability of the inspection based on the suspected defective image. The inspection unit changes the pixel value based on the attenuation rate of the X-rays of the substance corresponding to the virtual foreign object.

2. The X-ray inspection apparatus according to claim 1, wherein, The inspection unit changes the pixel value based on at least one of the X-ray transmission distance in the virtual foreign object, the density of the substance, and the mass absorption coefficient of the substance.

3. The X-ray inspection apparatus according to claim 2, wherein, The transmission distance is the length of the portion of the virtual straight line connecting the irradiation part and the sensor part that passes through the virtual foreign object.

4. The X-ray inspection apparatus according to any one of claims 1 to 3, wherein, The sensor unit has a plurality of detection elements arranged in a cross direction that horizontally intersects the conveying direction of the conveying unit. The inspection unit changes the pixel value based on the attenuation rate of the X-rays calculated corresponding to each of the plurality of detection elements.

5. The X-ray inspection apparatus according to any one of claims 1 to 4, wherein, The inspection unit stores information on a plurality of virtual foreign objects that are different in at least one of size, shape, and density, and changes the pixel value based on the attenuation rate of the X-rays of the substance corresponding to the virtual foreign object selected from the plurality of virtual foreign objects.

6. The X-ray inspection apparatus according to any one of claims 1 to 5, wherein, When the inspection department obtains an inspection result that does not include the foreign object through the inspection based on the suspected defective image, it determines that there is a problem with the reliability of the inspection.

7. The X-ray inspection apparatus according to any one of claims 1 to 6, wherein, The inspection department generates the suspected defective image and automatically performs the inspection after a preset time has elapsed or after inspecting a preset number of the items.

8. The X-ray inspection apparatus according to any one of claims 1 to 7, wherein, The inspection unit generates the suspected defective image by extracting the shape of the item included in the inspection image and changing the pixel value of a portion of the pixels on the inner side of the extracted shape.

9. The X-ray inspection apparatus according to any one of claims 1 to 8, wherein, When the inspection department obtains an inspection result excluding the foreign object based on the inspection image excluding the virtual foreign object during the execution of the inspection, it controls the sorting department to sort the items in a direction different from the direction in which the normal items excluding the foreign object are sorted by the sorting department during the non-execution of the inspection. When the inspection unit obtains an inspection result excluding the foreign object through the inspection based on the suspected defective image during the execution of the inspection, it stops the transport of the article through the transport unit.

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