X-ray device

Abstract

To provide an X-ray device that suppresses the misrecognition of the length of an object. [Solution] The X-ray apparatus 10 includes a conveyor for transporting articles, an X-ray irradiator 13, an X-ray line sensor 14 for detecting X-rays in the detection area where the articles are transported, and a control computer 20. The control computer 20 has a first threshold and a second threshold as thresholds, and detects the front and rear ends of articles by comparing the detected value of the X-ray line sensor 14 with the threshold. The control computer 20 switches the threshold from the first threshold to the second threshold after the front end of the article has passed the detection area and before the rear end of the article has passed the detection area.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2009-270866) discloses an apparatus that irradiates an article to be inspected with X-rays to perform various inspections on the article. Articles determined to be defective in this apparatus are sorted by a sorting mechanism arranged on the downstream side of the apparatus and collected in a collection box located at a place outside the conveyance path.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In the above apparatus, based on the detection result of the X-ray detection unit, the length in the conveyance direction of each article is specified, and this information is sent to the sorting mechanism so that the sorting operation is performed at an appropriate timing.

[0004] However, for example, in a chicken inspection line, an article (chicken) may be conveyed in a state where the skin part extends long behind the main body part of the meat. In such a case, the main body part and the skin part with different thicknesses cannot be detected as the same article, and the apparatus may erroneously recognize the main body part as the first article and the subsequent skin part as the second article. Then, the incorrect information on the length of the first article and the length of the second article will be sent to the sorting device. However, since it is actually one article, the sorting operation will be performed at the timing when the first article or the second article is conveyed. As a result, there will be a problem that the one article is not properly collected in the defective product collection box.

[0005] An object of the present invention is to provide an X-ray apparatus in which misrecognition of the length of a conveyed article is suppressed.

Means for Solving the Problems

[0006] The X-ray apparatus according to the first aspect comprises a transport unit, an X-ray irradiation unit, an X-ray detection unit, and a control unit. The transport unit transports an article. The X-ray irradiation unit irradiates the article being transported by the transport unit with X-rays. The X-ray detection unit detects X-rays in the detection area where the article is being transported. The control unit compares the detected value from the X-ray detection unit with a threshold value to detect the front and rear ends of the article in the transport direction. The control unit has a first threshold value and a second threshold value. The control unit switches the threshold value from the first threshold value to the second threshold value after the front end of the article has passed the detection area and before the rear end of the article has passed the detection area.

[0007] In this X-ray apparatus, the threshold switches from the first threshold to the second threshold after the front end of the article has passed the detection area and before the rear end of the article has passed the detection area. Therefore, for example, when detecting the front and rear ends of an article with different thicknesses at the front and rear ends in the direction of transport using the X-ray apparatus, the detection accuracy is improved. This suppresses the misrecognition of the length of the transported article in the direction of transport.

[0008] Furthermore, detection of the front and rear ends of an item passing through the detection area may be performed using the detection results of the X-ray detection unit, or it may be performed by deploying sensors or cameras separately from the X-ray detection unit.

[0009] The X-ray apparatus relating to the second viewpoint is the same as the X-ray apparatus relating to the first viewpoint, and the control unit switches the threshold from the first threshold to the second threshold when it determines that the front end of the article has passed the detection area. The control unit switches the threshold from the second threshold to the first threshold when it determines that the rear end of the article has passed the detection area.

[0010] In this X-ray device, when it is determined that the trailing edge of an object has passed the detection area, the threshold switches from the second threshold to the first threshold, allowing the trailing edge of a subsequent object to be properly detected by the first threshold.

[0011] The X-ray apparatus relating to the third viewpoint is an X-ray apparatus relating to the first or second viewpoint, and the control unit calculates the length of the article in the transport direction by detecting the front end and rear end of the article.

[0012] This X-ray device can transmit the calculated length information of an object to an external source.

[0013] The X-ray apparatus relating to the fourth perspective is the same as the X-ray apparatus relating to the third perspective, and a separate item sorting device is provided downstream in the direction of item transport. The control unit of the X-ray apparatus sends the calculation result of the item length to the item sorting device.

[0014] This X-ray system allows the item sorting device to perform sorting operations at the appropriate timing.

[0015] The X-ray apparatus relating to the fifth viewpoint is an X-ray apparatus relating to either the first viewpoint or the fourth viewpoint, and the control unit determines whether the front end of the article has passed the detection area based on the detection result of the X-ray detection unit.

[0016] This X-ray system determines when the front edge of an object has passed the detection area based on the detection result of the X-ray detection unit, eliminating the need for other sensors or cameras and thus reducing costs.

[0017] The X-ray apparatus relating to the sixth perspective is the X-ray apparatus relating to the fifth perspective, where the second threshold is greater than the first threshold. The control unit determines that the front end of the article has passed the detection area when the detected value of the X-ray detection unit falls below the first threshold. The control unit determines that the rear end of the article has passed the detection area when the detected value of the X-ray detection unit exceeds the second threshold.

[0018] The X-ray apparatus relating to the seventh viewpoint is an X-ray apparatus relating to either the first viewpoint or the sixth viewpoint, and the control unit automatically determines the second threshold value from the first threshold value.

[0019] In this X-ray apparatus, the second threshold value can be automatically calculated from the first threshold value determined by inputting and adjusting by actually passing an article through the detection area of the X-ray detection unit at the production site. As a result, the costs and man-hours for trial operation and adjustment operation can be suppressed.

[0020] The X-ray apparatus according to the eighth aspect is the X-ray apparatus according to the first aspect or the second aspect, wherein the control unit compares the amount of decrease per unit time of the detection value of the X-ray detection unit with the first threshold value, and determines that the front end of the article has passed through the detection area. The control unit compares the amount of increase per unit time of the detection value of the X-ray detection unit with the second threshold value, and determines that the rear end of the article has passed through the detection area.

Advantages of the Invention

[0021] According to the X-ray apparatus of the present invention, it is possible to suppress misrecognizing the length of the conveyed article.

Brief Description of the Drawings

[0022] [Figure 1] An external perspective view of an X-ray apparatus according to an embodiment of the present invention. [Figure 2] An internal configuration diagram of a shield box of the X-ray apparatus. [Figure 3] A schematic diagram showing the principle of X-ray inspection. [Figure 4] A diagram showing the processes before and after the X-ray apparatus. [Figure 5] A block diagram of a control computer. [Figure 6] A diagram showing a control flow for detecting the front end and the rear end of an article. [Figure 7] A diagram showing an X-ray image of chicken, which is an example of an article to be inspected. [Figure 8A] A diagram showing an X-ray image when only the main body part of a lump of chicken is erroneously recognized as one article. [Figure 8B] A diagram showing an X-ray image when only the skin part at the rear end of a lump of chicken is erroneously recognized as one article.

Modes for Carrying Out the Invention

[0023] Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.

[0024] (1) Overall configuration of the X-ray apparatus Figure 1 is an external perspective view of an X-ray apparatus 10 according to one embodiment of the present invention. In Figure 1, the X-ray apparatus 10 is one of the devices incorporated into a production line (see Figure 4) to perform quality inspection of articles G, and is a device that determines the quality of articles G by irradiating them with X-rays as they are continuously transported.

[0025] The sample item G is transported to the X-ray apparatus 10 by the upstream conveyor 60. Item G is classified as either good or defective in the X-ray apparatus 10. The inspection results from the X-ray apparatus 10 are sent to the item sorting device 70 located downstream of the X-ray apparatus 10.

[0026] The item sorting device 70 sends items G that have been determined to be good by the X-ray device 10 to the conveyor 80 that discharges normal items, and sorts items G that have been determined to be defective by the X-ray device 10 to the defective item discharge direction 90 or defective item discharge direction 91. The item sorting device 70 is a separate device from the X-ray device 10. The item sorting device 70 recognizes the entry of items G into the device by a light-emitting and light-receiving photoelectric sensor installed at the entrance, and determines the timing of the sorting operation based on the length information of the items G in the transport direction sent from the item length calculation unit 21e of the X-ray device 10, which will be described later. The item sorting device 70 sorts the items G by moving guide members or by activating an air jet mechanism.

[0027] (2) Detailed configuration Figure 2 is an internal configuration diagram of the shield box 11 of the X-ray apparatus 10. As shown in Figures 1 and 2, the X-ray apparatus 10 mainly consists of the shield box 11, a conveyor 12, an X-ray irradiator 13, an X-ray line sensor 14, a monitor 30 with touch panel functionality (see Figure 1), and a control computer 20 (see Figure 5).

[0028] (2-1) Shield box 11 Openings 11a are formed on both sides of the shield box 11 to allow articles G to be moved in and out of the shield box 11. The openings 11a are covered by a shielding curtain (not shown) to prevent X-ray leakage to the outside of the shield box 11. This shielding curtain is molded from lead-containing rubber and is designed to be pushed aside by the articles G as they pass through the openings 11a.

[0029] The shield box 11 houses the conveyor 12, X-ray irradiator 13, X-ray line sensor 14, control computer 20, and other components. A monitor 30 and power switch are located on the upper front of the shield box 11.

[0030] (2-2) Conveyor 12 The conveyor 12 is a transport unit that transports articles G within the shield box 11, and as shown in Figure 1, it is positioned to pass through openings 11a formed on both sides of the shield box 11. The conveyor 12 transports articles G placed on the belt by rotating an endless belt with drive rollers driven by a conveyor motor 12a (see Figure 5).

[0031] The conveying speed of the conveyor 12 is precisely controlled by the inverter control of the conveyor motor 12a by the control computer 20 so that it reaches the set speed entered by the operator. The conveyor motor 12a is also equipped with an encoder 12b (see Figure 5) that detects the conveying speed of the conveyor 12 and sends the information to the control computer 20.

[0032] (2-3)X-ray irradiator 13 As shown in Figure 2, the X-ray irradiator 13, which serves as the X-ray irradiation unit, is positioned above the conveyor belt 12 and irradiates X-rays into a fan-shaped irradiation area X towards the X-ray line sensor 14 below. In other words, the X-ray irradiator 13 irradiates the items G being transported by the conveyor belt 12 with X-rays.

[0033] (2-4) X-ray line sensor 14 Figure 3 is a schematic diagram illustrating the principle of X-ray inspection. In Figure 3, the X-ray line sensor 14, which acts as the X-ray detection unit, is positioned below the conveyor belt 12 and has a large number of pixel sensors 14a. The number of pixel sensors 14a in this X-ray line sensor 14 is several hundred or more than a thousand. These pixel sensors 14a are arranged horizontally in a straight line perpendicular to the direction of transport by the conveyor belt 12. Each pixel sensor 14a detects X-rays that have passed through the object G or the conveyor belt 12 and outputs an X-ray fluoroscopic image signal. The X-ray fluoroscopic image signal indicates the brightness (density) of the X-rays.

[0034] In the X-ray apparatus 10, the space directly above the X-ray line sensor 14 inside the shield box 11 is the detection area S. In Figure 2, the width dimension of the detection area S in the transport direction (direction of the white arrow in Figure 2) is shown enlarged for ease of understanding, but the width of the detection area S is equal to the width dimension of the pixel sensor 14a, and the actual width dimension is smaller.

[0035] The X-ray line sensor 14 detects X-rays that have passed through the item G and the conveyor 12 in the detection area S where the item G is being transported.

[0036] (2-5) Monitor 30 Monitor 30 is a full-dot LCD display that shows a screen prompting the operator to input inspection parameters and other information required during inspection. Monitor 30 also has a touch panel function to accept input of inspection parameters and other information from the operator.

[0037] (2-6) Control computer 20 Figure 5 is a block diagram of the control computer 20. In Figure 5, the control computer 20 has a CPU (Central Processing Unit) 21, ROM (Read-Only Memory) 22, RAM (Random Access Memory) 23, HDD (Hard Disk Drive) 25, and a drive 24 for inserting storage media, etc.

[0038] The CPU 21 executes various programs stored in the ROM 22 or HDD 25. The HDD 25 stores inspection parameters and inspection results. Inspection parameters can be set and changed by the operator using the touch panel function of the monitor 30.

[0039] Furthermore, the control computer 20 also includes a display control circuit (not shown) that controls the display of data on the monitor 30, a key input circuit (not shown) that captures key input data entered by the operator via the touch panel of the monitor 30, and a communication port (not shown) that enables connection to external devices such as a printer (not shown) and a network such as a LAN.

[0040] Furthermore, the various parts 21-25 of the control computer 20 are interconnected via bus lines such as an address bus and a data bus.

[0041] Furthermore, the control computer 20 is connected to the conveyor motor 12a, encoder 12b, X-ray irradiator 13, X-ray line sensor 14, etc.

[0042] (3) Configuration of CPU21 The HDD 25 of the control computer 20 stores inspection programs, including an item end detection module, an image generation module, an area identification module, a weight estimation module, a weight diagnostic module, a foreign object inspection module, a spacing detection module, and an impingement estimation module. The CPU 21 of the control computer 20 reads and executes these program modules, thereby operating as functional units such as the item front / rear end determination unit 21a, the image generation unit 21b, the area identification unit 21c, the foreign object inspection unit 21d, and the item length calculation unit 21e (see Figure 5). Here, among the many program modules, the item end detection module, the image generation module, the area identification module, and the foreign object inspection module are given as examples, and the item front / rear end determination unit 21a, the image generation unit 21b, the area identification unit 21c, the foreign object inspection unit 21d, and the item length calculation unit 21e, which operate as a result of their execution, are described.

[0043] (3-1) Article front and rear end determining section 21a The CPU 21, which operates as the article front / rear end determination unit 21a (hereinafter referred to as the article front / rear end determination unit 21a), detects and determines the ends of the article G in accordance with the control flow shown in Figure 6. The article front / rear end determination unit 21a detects the front and rear ends of the article G in the transport direction by comparing the detected value of the X-ray line sensor 14 (the output value of the X-ray fluoroscopic image signal output by the pixel sensor 14a) with a threshold. The article front / rear end determination unit 21a has a first threshold and a second threshold as thresholds. The article front / rear end determination unit 21a switches the threshold from the first threshold to the second threshold after the front end of the article G has passed through the detection area S and before the rear end of the article G has passed through the detection area S.

[0044] The front / rear end determination unit 21a then switches the threshold from the first threshold to the second threshold when it determines that the front end of the item G has passed through the detection area S. Furthermore, the front / rear end determination unit 21a then switches the threshold from the second threshold to the first threshold when it determines that the rear end of the item G has passed through the detection area S.

[0045] The operation of the front and rear end determination unit 21a of the article described above will be explained with reference to Figure 6.

[0046] In step S1, the front and rear end determination unit 21a of the article sets the threshold to the first threshold.

[0047] In step S2, the front / rear end determination unit 21a extracts the average or minimum value of the darkest few output values ​​from the many pixel sensors 14a of the X-ray line sensor 14, and compares that value with a threshold (first threshold). If it is determined in step S2 that the value is below the first threshold, the process moves to step S3, where the front / rear end determination unit 21a determines that the front end of the article G has passed through the detection area S, and determines the front end position of the article G.

[0048] In step S2, if the extracted value is not below the first threshold, that is, if the extracted value is less than or equal to the first threshold, it is determined that item G has not yet entered the detection area S, and the determination in step S2 is repeated.

[0049] After determining the front end position of article G in step S3, the article front / rear end determination unit 21a immediately sets the threshold to the second threshold in step S4. The second threshold is a value greater than the first threshold (a brighter value).

[0050] In step S5, the article front / rear end determination unit 21a extracts the average or minimum value of the few darkest pixels from the output values ​​of hundreds or thousands or more of the pixel sensors 14a of the X-ray line sensor 14, and compares that value with a threshold (second threshold). If it is determined in step S5 that the value exceeds the second threshold, the process moves to step S6, where the article front / rear end determination unit 21a determines that the rear end of article G has passed through the detection area S, and determines the position of the rear end of article G.

[0051] (3-2) Image generation section 21b The CPU 21, which operates as the image generation unit 21b (hereinafter referred to as the image generation unit 21b), generates an X-ray transmission image of the object G based on the X-ray fluoroscopic image signal output from the X-ray line sensor 14. The image generation unit 21b acquires the X-ray fluoroscopic image signal output from each pixel sensor 14a of the X-ray line sensor 14 at fine time intervals and generates an X-ray transmission image of the object G based on the acquired X-ray fluoroscopic image signal. Note that the fact that the front and rear ends of the object G have passed through the detection region S is determined by the object front / rear end determination unit 21a as described above. The image generation unit 21b generates an X-ray transmission image of the object G using the X-ray fluoroscopic image signal from slightly before the front end of the object G passes through the detection region S until slightly after the rear end of the object G passes through the detection region S. The image generation unit 21b generates an X-ray transmission image of the object G by concatenating the data on the brightness of the X-rays obtained from each pixel sensor 14a of the X-ray line sensor 14 at fine time intervals in a matrix in a time series.

[0052] (3-3) Area identification part 21c The CPU 21, which operates as a region identification unit 21c (hereinafter referred to as the region identification unit 21c), identifies the region of an item from the X-ray transmission image of the item G generated by the image generation unit 21b. The region identification unit 21c calculates the average value of the X-ray density values ​​of the pixel sensors 14a output from each of the numerous pixel sensors 14a at the same timing, and uses the calculated value as a representative value of the X-ray density value at that timing. It then checks (true / false determination) whether or not this representative value falls within a predetermined range. The region identification unit 21c superimposes the X-ray transmission image P generated by the image generation unit 21b with the result of the true / false determination process, and defines the region corresponding to the target range as the item region.

[0053] (3-4) Foreign object inspection department 21d The CPU 21, which operates as the foreign object inspection unit 21d (hereinafter referred to as the foreign object inspection unit 21d), detects foreign objects contained in the item G by performing a binarization process on the X-ray transmission image P of the item G generated by the image generation unit 21b. More specifically, as shown in Figure 3, if there is a region that appears darker than a preset inspection threshold on the X-ray transmission image P of the item G, it is determined that the item G contains foreign objects and that the item G is abnormal.

[0054] (3-5) Article length calculation section 21e The CPU 21, which operates as an item length calculation unit 21e (hereinafter referred to as the item length calculation unit 21e), calculates the length of item G in the transport direction from the front and rear end positions of item G determined by the item front and rear end determination unit 21a described above. The item length calculation unit 21e then sends the calculated length of item G to the item sorting device 70.

[0055] (4) Features (4-1) In the X-ray apparatus 10, a control computer 20 having a CPU 21 detects the front and rear ends of the article G in the transport direction by comparing the detected value of the X-ray line sensor 14 with a threshold. There are a first threshold and a second threshold. The article front / rear end determination unit 21a of the control computer 20 switches the threshold from the first threshold to the second threshold between steps S3 and S6 in Figure 6, that is, after the front end of the article G has passed through the detection area S and before the rear end of the article G has passed through the detection area S.

[0056] Therefore, when detecting the front and rear ends of an item G with different thicknesses in the front and rear portions in the transport direction using the X-ray device 10, the detection accuracy is improved. In particular, the X-ray device 10 is effective for items G with irregular shapes and a portion with less thickness at the rear end.

[0057] For example, if the cut chicken shown in Figure 7 is item G, its shape and planar size are not constant, and when item G is being transported, the thin skin portion CS tends to extend from the main body portion CM of the chicken to the rear end (posture). In such an item G, while the front end is easy to detect, the small thickness of the skin portion CS can lead to misdetection of the rear end. If the sorting device 70 mistakenly detects that item G is interrupted at the boundary between the main body portion CM and the skin portion CS in Figure 7, and mistakenly recognizes the main body portion CM shown in Figure 8A as one item G1 and the skin portion CS shown in Figure 8B as one item G2, then the length information of items G1 and G2, which is the result of the misdetection, will be sent to the item sorting device 70. In that case, if a foreign object is detected in the skin portion CS as shown in Figures 7 and 8B, the item sorting device 70 will operate to sort only the skin portion CS that was mistakenly identified as item G2. In this configuration, since the leather portion CS is actually integrated with the main body portion CM, items G whose center of gravity lies on the main body portion CM side will be transported downstream as normal items without being sorted.

[0058] Such false detection of item G is less likely to occur in the X-ray apparatus 10 of this embodiment. In other words, the X-ray apparatus 10 is designed to suppress the misrecognition of the length of the item G being transported.

[0059] (4-2) In the X-ray apparatus 10, when it is determined that the front end of the item G has passed the detection area S, the threshold is immediately switched from the first threshold to the second threshold (see step S4 in Figure 6). Similarly, when it is determined that the rear end of the item G has passed the detection area S, the threshold is immediately switched from the second threshold to the first threshold (see step S1 following step S6 in Figure 6). Therefore, even if the length of the item G in the transport direction is short, or if the transport interval between multiple items G is short, the front and rear ends of the item G can be reliably detected.

[0060] (4-3) In the X-ray apparatus 10, the article length calculation unit 21e sends the calculation result of the length of article G to the article sorting device 70. This allows the article sorting device 70 to control the actuators that perform the sorting operation so that, for example, force is applied to the vicinity of the center of the length of article G in the conveying direction. For example, if a mechanism is used that sorts articles G on a conveyor by rotating a guide member, the timing of that rotation can be set to an appropriate timing. Also, for example, if an air jet mechanism is used that sorts articles G on a conveyor by spraying high-pressure air from the side, the high-pressure air can be appropriately sprayed to the vicinity of the center of the length of article G.

[0061] (4-4) In the X-ray apparatus 10, the detection result of the X-ray line sensor 14 determines whether the edge of the object G has passed through the detection area S, eliminating the need for other sensors or cameras. This allows for a reduction in the cost of the X-ray apparatus 10.

[0062] (5) Variant (5-1) In the above embodiment, the functions of the X-ray device 10 include determining the end of the article G and calculating the length of the article G, as well as foreign object inspection to detect foreign objects (metal fragments or bone fragments) contained in the article G as an inspection process. However, as mentioned above, the X-ray device 10 may also perform inspection processes other than foreign object contamination inspection, such as weight estimation, weight diagnosis, and bite estimation. Furthermore, the control computer 20 of the X-ray device 10 may be made to perform a quantity estimation process to estimate the number of articles G inside the package.

[0063] (5-2) In the above embodiment, the front and rear end determination unit 21a extracts the average or minimum value of the darkest few output values ​​from the many pixel sensors 14a of the X-ray line sensor 14 and compares it with a threshold. It is preferable to change which of the many pixel sensors 14a output values ​​is extracted and adopted as a representative value depending on the shape, size, and properties of the article G.

[0064] Furthermore, in the above embodiment, the output value of the pixel sensor 14a of the X-ray line sensor 14 is compared with the threshold value itself. Alternatively, the decrease or increase in the output value of the pixel sensor 14a per unit time may be compared with the threshold value. For example, the decrease in the detected value per unit time may be compared with a first threshold value to determine that the front end of the item G has passed the detection area S, and the increase in the detected value per unit time may be compared with a second threshold value to determine that the rear end of the item G has passed the detection area S.

[0065] (5-3) In the above embodiment, the detection result of the X-ray line sensor 14 is used to detect when the end of the item G has passed through the detection area S. Alternatively, a photoelectric sensor may be placed at the entrance of the X-ray apparatus 10 to calculate the timing when the item G reaches the detection area S, or a CCD camera may be placed inside the shield box 11 to confirm when the item G enters or leaves the detection area S.

[0066] (5-4) In the above embodiment, the first and second threshold values ​​of the article front and rear end determination unit 21a are not described in detail, but it is necessary to change the threshold values ​​depending on the type and thickness of the article G, the X-ray transmittance, etc., and it is necessary to adjust the threshold values ​​by running actual articles G through them during trial runs or when starting use in the field.

[0067] Therefore, both the first and second thresholds basically need to be adjusted and set manually. However, for items where there is a certain relationship between the first and second thresholds, it is possible to manually adjust only one of them and have the other calculated automatically. In this case, for example, when the first threshold is set manually, the control computer 20 reads the relationship formula between the first and second thresholds from the product master (a collection of information about items G) stored in the HDD 25 or ROM 22, and automatically determines the second threshold from the first threshold. [Explanation of Symbols]

[0068] 10 X-ray equipment 12. Conveyor (transport section) 13 X-ray irradiator (X-ray irradiator) 14. X-ray line sensor (X-ray detection unit) 20. Control computer (control unit) 21 CPU (Control Unit) 70. Item sorting device G Goods S detection area [Prior art documents] [Patent Documents]

[0069] [Patent Document 1] Japanese Patent Publication No. 2009-270866

Claims

1. A conveying unit for transporting goods, An X-ray irradiation unit that irradiates the article being transported by the transport unit with X-rays, An X-ray detection unit that detects the X-rays in the detection area where the article is transported, A control unit that compares the detected value of the X-ray detection unit with a threshold value to detect the front and rear ends of the article in the transport direction, Equipped with, The control unit, The aforementioned thresholds include a first threshold and a second threshold, The threshold is switched from the first threshold to the second threshold after the front end of the article has passed the detection area and before the rear end of the article has passed the detection area. X-ray equipment.

2. The control unit, When it is determined that the front end of the article has passed the detection area, the threshold is switched from the first threshold to the second threshold. When it is determined that the rear end of the article has passed the detection area, the threshold is switched from the second threshold to the first threshold. The X-ray apparatus according to claim 1.

3. The control unit detects the front end and rear end of the article and calculates the length of the article in the transport direction. The X-ray apparatus according to claim 1 or 2.

4. A separate device from the X-ray apparatus, called an article sorting device, is provided downstream in the direction of transport of the aforementioned articles. The control unit sends the calculation result of the length of the article to the article sorting device. The X-ray apparatus according to claim 3.

5. The control unit determines, based on the detection result of the X-ray detection unit, that the front end of the article has passed through the detection area. The X-ray apparatus according to claim 1 or 2.

6. The second threshold is greater than the first threshold. The control unit, When the detection value of the X-ray detection unit falls below the first threshold, it is determined that the front end of the article has passed the detection area. When the detection value of the X-ray detection unit exceeds the second threshold, it is determined that the rear end of the article has passed the detection area. The X-ray apparatus according to claim 5.

7. The control unit automatically determines the second threshold from the first threshold. The X-ray apparatus according to claim 1 or 2.

8. The control unit, The amount of decrease per unit time of the detected value of the X-ray detection unit is compared with the first threshold value to determine that the front end of the article has passed the detection area. The increase in the detected value per unit time of the X-ray detection unit is compared with the second threshold to determine that the rear end of the article has passed the detection area. The X-ray apparatus according to claim 1 or 2.

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