JP2008175691A - X-ray inspection apparatus and inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and precisely an inspect abnormality of the shape of an article using an X-ray. <P>SOLUTION: An X-ray inspection apparatus 10 includes an image generation part 21a, an inspection region extraction part 21b, an envelope figure deriving part 21c, and inspection parts 21d, 21e. The image generating part 21a generates an X-ray image 61 of sausages S1, S2. The inspection region extracting part 21b extracts inspection regions B1, B2 from the X-ray image 61. The inspection regions B1, B2 are the regions that correspond to the sausages S1, S2. The envelope figure deriving part 21c derives envelope figures C1, C2. The envelope figures C1, C2 are figures which include the overall the inspection regions B1, B2 and keep an area minimum out of figures, in which the outer periphery is expressed by only a projection line. The inspection parts 21d, 21e inspect the shape of the sausages S1, S2 from the envelope figures C1, C2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray inspection apparatus and an inspection method for inspecting the shape of an article using X-rays.

  In a production line for commodities such as food, an inspection may be performed by an X-ray inspection apparatus in order to avoid shipping such commodities when there is an abnormality in the shape of the commodities. In such an X-ray inspection apparatus, X-rays are irradiated to articles continuously conveyed, and an X-ray dose transmitted through the articles is detected by an X-ray line sensor. Then, by performing image processing on the X-ray image obtained based on the X-ray dose, it is determined whether there is an abnormality in the shape of the article.

  When inspecting an article using such an X-ray inspection apparatus, it is common to perform pattern matching between an X-ray image of an article to be inspected and a predetermined reference image (for example, Patent Documents). 1).

In addition, in the X-ray inspection apparatus described in Patent Document 2, the integrated number of pixels constituting the periphery of an object to be inspected is calculated, and the article is determined depending on whether the integrated number is within a predetermined range. The presence or absence of cracks or cracks is determined. That is, in Patent Document 2, the cumulative number of pixels that form the periphery of an article to be inspected is considered to be proportional to the peripheral length of the article.
JP 2002-98652 A JP 2002-310946 A

  However, when a pattern matching method as disclosed in Patent Document 1 is adopted, it is necessary to perform a similarity determination process between complex images, and the time required for the image processing becomes long.

  However, in an X-ray inspection apparatus deployed in a product production line that requires high speed, it is required to shorten the inspection time as much as possible. Of course, if expensive hardware or software is used, pattern matching processing can be performed at high speed. However, in reality, it is important to increase the speed and reduce the cost.

  In addition, when the perimeter measurement method as shown in Patent Document 2 is adopted, an error increases depending on an article to be inspected, and it is difficult to perform an accurate inspection. In particular, if the shape of the article to be inspected is complex or contains many curved parts, the cumulative number of pixels that form the periphery of the article to be inspected is proportional to the perimeter of the article. There are many things that must be avoided.

  An object of the present invention is to simply and accurately inspect abnormalities in the shape of an article using X-rays.

  An X-ray inspection apparatus according to a first invention includes an irradiation unit, a light receiving unit, a generation unit, an extraction unit, a derivation unit, and an inspection unit. The irradiation unit irradiates the article with X-rays. The light receiving unit receives X-rays from the irradiation unit. The generation unit generates an X-ray image based on the X-rays received by the light receiving unit. The extraction unit extracts an examination region from the X-ray image. An inspection area is an area corresponding to an article. The deriving unit derives an envelope graphic. The envelope figure is a figure that includes the entire inspection region and has the smallest area among the figures that are expressed only by convex lines on the outer periphery. The inspection unit inspects the shape of the article based on the envelope figure.

  In this X-ray inspection apparatus, an area occupied by the article (inspection area) is extracted from an X-ray image of the article, an envelope graphic of the extracted inspection area is derived, and the shape of the article is derived based on the derived envelope graphic. Is inspected. Thereby, in this X-ray inspection apparatus, it is possible to easily and accurately inspect abnormalities in the shape of the article.

  An X-ray inspection apparatus according to a second invention is the X-ray inspection apparatus according to the first invention, and includes an irradiation unit, a light receiving unit, a generation unit, an extraction unit, a derivation unit, and an inspection unit. The irradiation unit irradiates the article with X-rays. The light receiving unit receives X-rays from the irradiation unit. The generation unit generates an X-ray image based on the X-rays received by the light receiving unit. The extraction unit extracts an examination region from the X-ray image. The inspection area is an area corresponding to another article or space surrounded by the article. The deriving unit derives an envelope graphic. The envelope figure is a figure that includes the entire inspection region and has the smallest area among the figures that are expressed only by convex lines on the outer periphery. The inspection unit inspects the shape of the article based on the envelope figure.

  In this X-ray inspection apparatus, an area (inspection area) occupied by another article surrounded by the article or a space surrounded by the article is extracted from an X-ray image of the article, and an envelope figure of the extracted inspection area is derived. The shape of the article is inspected based on the derived envelope graphic. Thereby, in this X-ray inspection apparatus, it is possible to easily and accurately inspect abnormalities in the shape of the article.

  An X-ray inspection apparatus according to a third aspect of the present invention is the X-ray inspection apparatus according to the first or second aspect of the present invention, wherein the inspection unit derives a recessed area and compares the area of the recessed area with a predetermined threshold value. Inspect the shape of the article. A dent area | region is an area | region which deducted the test | inspection area | region from the envelope figure.

  In this X-ray inspection apparatus, the indented region included in the envelope graphic is derived by subtracting the inspection region from the envelope graphic including the inspection region. Then, the shape of the article is inspected according to the area of the recessed area. Thereby, in this X-ray inspection apparatus, the shape of the article can be inspected more accurately.

  An X-ray inspection apparatus according to a fourth aspect is the X-ray inspection apparatus according to the first aspect, wherein the article has an elongated shape. The inspection unit inspects the degree of bending of the article.

  In this X-ray inspection apparatus, the degree of curvature of an article having an elongated shape can be inspected more accurately.

  An X-ray inspection apparatus according to a fifth aspect is the X-ray inspection apparatus according to the second aspect, wherein the article is a container having an internal space. The inspection unit inspects the degree of depression of the article.

  In this X-ray inspection apparatus, it is possible to more accurately inspect the degree of dent of a container having an internal space.

  The inspection method according to the sixth aspect comprises an extraction step, a derivation step, and an inspection step. The extraction step is a step of extracting the inspection region from the X-ray image of the article. An inspection area is an area corresponding to an article. The derivation step is a step of deriving an envelope graphic. The envelope figure is a figure that includes the entire inspection region and has the smallest area among the figures that are expressed only by convex lines on the outer periphery. The inspection step is a step of inspecting the shape of the article based on the envelope figure.

  In this inspection method, an area occupied by the article (inspection area) is extracted from the X-ray image of the article, an envelope graphic of the extracted inspection area is derived, and the shape of the article is inspected based on the derived envelope graphic Is done. Thereby, in this inspection method using X-rays, it is possible to easily and accurately inspect abnormalities in the shape of the article.

  The inspection method according to the seventh aspect comprises an extraction step, a derivation step, and an inspection step. The extraction step is a step of extracting the inspection region from the X-ray image of the article. The inspection area is an area corresponding to another article or space surrounded by the article. The derivation step is a step of deriving an envelope graphic. The envelope figure is a figure that includes the entire inspection region and has the smallest area among the figures that are expressed only by convex lines on the outer periphery. The inspection step is a step of inspecting the shape of the article based on the envelope figure.

  In this inspection method, an area (inspection area) occupied by another article surrounded by the article or a space surrounded by the article (inspection area) is extracted from the X-ray image of the article, and an envelope figure of the extracted inspection area is derived and derived. The shape of the article is inspected based on the enveloped figure. Thereby, in this inspection method using X-rays, it is possible to easily and accurately inspect abnormalities in the shape of the article.

  In the present invention, an area occupied by the article (inspection area), or another article surrounded by the article or an area occupied by the space surrounded by the article (inspection area) is extracted and extracted from the X-ray image of the article. An envelope graphic of the inspection area is derived, and the shape of the article is inspected based on the derived envelope graphic. Thereby, in this X-ray inspection apparatus, it is possible to easily and accurately inspect abnormalities in the shape of the article.

  Hereinafter, X-ray inspection apparatuses 10 and 110 and an inspection method according to first and second embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 shows an appearance of an X-ray inspection apparatus 10 according to the first embodiment of the present invention. The X-ray inspection apparatus 10 is one of the apparatuses that inspect the quality of the product G in the production line of the product G such as food, and irradiates the product G that is continuously conveyed with X-rays, This is a device that determines the defect of the product G based on the amount of X-rays transmitted through the product G.

  As shown in FIG. 4, the product G, which is a specimen of the X-ray inspection apparatus 10, is conveyed to the X-ray inspection apparatus 10 by the front conveyor 60. The product G is classified as a good product or a defective product in the X-ray inspection apparatus 10. The inspection result obtained by the X-ray inspection apparatus 10 is sent to a distribution mechanism 70 disposed on the downstream side of the X-ray inspection apparatus 10. The distribution mechanism 70 sends the product G to the regular line conveyor 80 when the product G is determined to be a non-defective product in the X-ray inspection device 10, and the product G is determined to be a defective product in the X-ray inspection device 10. In this case, the product G is distributed to the defective product storage conveyor 90.

(Configuration of X-ray inspection equipment)
As shown in FIGS. 1, 2 and 5, the X-ray inspection apparatus 10 mainly includes a shield box 11, a conveyor 12, an X-ray irradiator (irradiation unit) 13, and an X-ray line sensor (light receiving unit). 14, a monitor 30 with a touch panel function, and a control computer 20.

[Shield box]
On both side surfaces of the shield box 11, openings 11 a for carrying the product G in and out of the shield box 11 are formed. In the shield box 11, a conveyor 12, an X-ray irradiator 13, an X-ray line sensor 14, a control computer 20 and the like are accommodated.

  In addition, in order to suppress the leakage of X-rays to the outside of the shield box 11, the opening 11a is blocked by a shielding noren (not shown). This shielding nolen is formed from rubber containing lead, and is pushed away by the product G when the product G passes through the opening 11a.

  In addition to the monitor 30, a key insertion slot, a power switch, and the like are disposed on the front upper portion of the shield box 11.

〔Conveyor〕
The conveyor 12 conveys the commodity G in the shield box 11 and is disposed so as to penetrate through the openings 11a formed on both side surfaces of the shield box 11 as shown in FIG. And the conveyor 12 conveys the goods G mounted on the belt, rotating an endless belt with the drive roller driven by the conveyor motor 12a (refer FIG. 5). The conveyance speed by the conveyor 12 is finely controlled by the inverter control of the conveyor motor 12a by the control computer 20 so as to be the set speed input by the user.

  The conveyor motor 12a is equipped with an encoder 12b (see FIG. 5) that detects the conveying speed of the conveyor 12 and sends it to the control computer 20.

[X-ray irradiator]
As shown in FIG. 2, the X-ray irradiator 13 is disposed above the conveyor 12 and irradiates the fan-shaped irradiation range X with X-rays toward the lower X-ray line sensor 14.

[X-ray line sensor]
The X-ray line sensor 14 is disposed below the conveyor 12 and receives X-rays transmitted through the conveyor 12. As shown in FIG. 3, the X-ray line sensor 14 is mainly composed of many pixel sensors 14a. These pixel sensors 14a are arranged in a straight line in the horizontal direction in a direction orthogonal to the conveying direction by the conveyor 12.

  FIG. 3 shows a transmission state of X-rays in the shield box 11 and a graph of the transmission amount of X-rays detected by each pixel sensor 14a in the transmission state.

〔monitor〕
The monitor 30 is a full-dot liquid crystal display, and displays a screen that prompts the user to input initial setting values and inspection parameters necessary for inspection. The monitor 30 also has a touch panel function, and accepts inputs such as initial setting values and inspection parameters from the user.

[Control computer]
As shown in FIG. 5, the control computer 20 includes a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, a RAM (Random Access Memory) 23, an HDD (Hard Disk) 25, and a storage medium for insertion. A drive 24 is provided.

  In the CPU 21, various programs stored in the HDD 25 are executed. In addition to various programs, the HDD 25 stores a threshold file 25a and an inspection result log file 25b. The threshold value file 25a stores a threshold value that is an inspection parameter, and the inspection result log file 25b stores and accumulates inspection images and inspection results for the product G determined to be defective by inspection. These data are stored and accumulated in a storage medium inserted in the drive 24 in place of or in addition to the HDD 25 according to user settings.

  Further, the control computer 20 includes a display control circuit (not shown) that controls data display on the monitor 30 and a key input circuit (not shown) that captures key input data input by the user via the touch panel of the monitor 30. ), And a communication port (not shown) that enables connection with an external device such as a printer (not shown) or an external network such as a LAN.

  And each part 21-25 etc. of the control computer 20 are mutually connected via bus lines, such as an address bus and a data bus.

  The control computer 20 is connected to a conveyor motor 12a, an encoder 12b, a photoelectric sensor 15, an X-ray irradiator 13, an X-ray line sensor 14, and the like. The photoelectric sensor 15 is a synchronous sensor for detecting the timing when the product G as a specimen passes through the fan-shaped X-ray irradiation range X (see FIG. 2), and is mainly a pair of sensors arranged with the conveyor 12 interposed therebetween. It consists of a projector and a light receiver.

(Determination of product defects by control computer)
The CPU 21 of the control computer 20 generates an X-ray image of the product G by reading and executing an image generation module included in the inspection program stored in the HDD 25. Further, the CPU 21 of the control computer 20 has one or more of a curvature inspection module, a foreign matter inspection module, a crack inspection module, and a quantity inspection module included in the inspection program stored in the HDD 25 according to a user setting. These inspection modules can be read out and executed. That is, according to the product G, the user of the X-ray inspection apparatus 10 confirms that the product G is not curved, foreign matter is not mixed in the product G, or the product G has no cracks, An inspection as to whether or not the quantity of the contents included in the product G is correct can be appropriately performed. Such curvature inspection, foreign object inspection, crack inspection, and quantity inspection by the control computer 20 are realized through image processing on the X-ray image of the product G.

  The user can also perform other inspections on the product G by upgrading the inspection module or adding a new one.

  The inspection results of the curvature inspection, foreign object inspection, crack chip inspection, and quantity inspection are sent to the distribution mechanism 70. The distribution mechanism 70 distributes the product G determined to be a non-defective product in all of these inspections to the regular line conveyor 80, and the product determined to be a defective product in at least one of these inspections. G is distributed to the defective product storage conveyor 90.

[Generation of X-ray images]
The CPU 21 of the control computer 20 operates as the image generation unit 21 a by reading and executing the image generation module stored in the HDD 25. The image generation unit 21a performs X-ray fluoroscopy indicating the amount of X-ray transmission (see FIG. 3) detected by the X-ray line sensor 14 when the product G passes through the fan-shaped X-ray irradiation range X (see FIG. 2). Image signals are acquired at fine time intervals, and an X-ray image of the product G is generated based on these X-ray fluoroscopic image signals. At this time, the timing at which the product G passes through the fan-shaped X-ray irradiation range X (see FIG. 2) is determined by a signal from the photoelectric sensor 15. That is, the image generation unit 21a includes the product G and the background portion thereof by connecting data for each fine time interval related to the X-ray transmission amount obtained from each pixel 14a of the X-ray line sensor 14 in time series. An X-ray image is generated.

[Bending inspection]
The CPU 21 of the control computer 20 operates as an inspection region extraction unit 21b, an envelope graphic deriving unit 21c, a recessed region deriving unit 21d, and a comparison unit 21e by reading and executing the curvature inspection module stored in the HDD 25. Each of these units 21b to 21e inspects the degree of curvature of the product G by performing image processing on the X-ray image of the product G generated by the image generation unit 21a.

  Hereinafter, with reference to FIG. 6 and FIG. 7, the details of the curvature inspection will be described by taking as an example the case where the elongated sausages S1 and S2 are used as specimens. In order to make the explanation easy to understand, one of the two sausages S1 and S2 is assumed to be a non-defective product that is linearly extended, and the other sausage S2 is a defective product that is greatly curved. On the X-ray image 61 shown in FIG. 6A, the dark area A1 appearing on the left side shows a non-defective sausage S1, and the dark area A2 appearing on the right side shows a defective sausage S2. .

  First, in step S71, the inspection area extraction unit 21b performs binarization processing to determine the area on the X-ray image 61 as the area B1 indicating the sausage S1, the area B2 indicating the sausage S2, and the background of the sausages S1 and S2. It is divided into region B3. Note that the X-ray image 61 that is the target of the binarization processing in step S71 is generated by the image generation unit 21a.

  In the binarization process, the value of the amount of X-ray transmission corresponding to each pixel constituting the X-ray image 61 is compared with a predetermined threshold value. Then, either “0” or “1” is assigned to each pixel according to the magnitude relationship between these values. “0” indicates an area corresponding to the sausages S1 and S2, and “1” indicates an area corresponding to the background of the sausages S1 and S2. Here, the threshold value used for the binarization processing is appropriately determined in advance according to the sausages S1 and S2 that are specimens by performing a test or the like before starting the test. It is assumed that the data is stored in the threshold file 25a of the HDD 25 by the user.

  An image 62 shown in FIG. 6B is an image after the binarization process is performed on the X-ray image 61. On the image 62, the area B1 appearing white on the left side corresponds to the sausage S1, the area B2 appearing white on the right side corresponds to the sausage S2, and the other area B3 appearing black represents the background of the sausages S1 and S2. Corresponding to That is, in step S71, the regions B1 and B2 corresponding to the sausages S1 and S2 are extracted from the X-ray image 61. Hereinafter, the areas B1 and B2 extracted as the areas corresponding to the sausages S1 and S2 in step S71 are referred to as inspection areas B1 and B2.

  Next, in step S72, the envelope figure deriving unit 21c derives the envelope figures C1 and C2 (see FIG. 6C) of the inspection regions B1 and B2 extracted in step S71. In addition, the envelope figure of a certain area means a figure that includes the entire area and has the smallest area among figures that are expressed only by a convex line on the outer periphery. In other words, the envelope figure of a certain area refers to a figure surrounded by a rubber band applied along the cross section of an object whose cross section has the same shape as that area. Further, the convex line means a line in which a line segment connecting any two points in a region surrounded by the line is always included in the region.

  In the image 63 shown in FIG. 6C, the envelope figure C1 that appears white on the left side is the envelope figure of the inspection region B1 on the image 62 shown in FIG. 6B, and the envelope figure that appears white on the right side. The figure C2 is an envelope figure of the inspection area B2 on the image 62 shown in FIG. The envelope figure C1 of the inspection area B1 corresponding to the sausage S1 extending in a straight line has the same shape as the inspection area B1. This is because the outer periphery of the inspection region B1 is originally represented only by a convex line because the sausage S1 extends linearly. On the other hand, the envelope figure C2 of the inspection area B2 corresponding to the curved sausage S2 has a substantially triangular shape, whereas the inspection area B2 is substantially V-shaped. More specifically, the envelope figure C2 is substantially the same as the triangle formed by straightly connecting the end points on the opposite side of the V-shaped vertex of the two line segments constituting the V-shaped inspection area B2. It has a shape. That is, the envelope figure of the inspection area corresponding to the curved product G has a larger area than the original inspection area.

  Next, in step S73, the recessed area deriving unit 21d derives recessed areas D1, D2 (see FIG. 6D) included in the envelope figures C1, C2 derived in step S72. A dent area | region means the area | region which deducted the test | inspection area | region extracted by step S71 from the envelope figure derived | led-out by step S72.

  Therefore, the recessed area D1 derived by subtracting the inspection area B1 having the same shape as the envelope figure C1 from the envelope figure C1 is an area having a zero area. For this reason, the dent area | region D1 does not appear on the image 64 shown in FIG.6 (d). On the other hand, as shown in FIG. 6D, the recessed area D2 derived by subtracting the inspection area B2 having a smaller area than the envelope figure C2 from the envelope figure C2 has a mountain shape.

Next, in step S74, the comparison unit 21e calculates areas E1 and E2 of the recessed regions D1 and D2 derived in step S73, and compares the areas E1 and E2 with a preset threshold value F. As a result of comparison, if the areas E1 and E2 of the recessed regions D1 and D2 are equal to or less than the threshold value F, the sausages S1 and S2 are determined to be non-defective products, and if larger than the threshold value F, the sausages S1 and S2 are determined to be defective products. Will be. The threshold value F is appropriately determined in advance in accordance with the sausages S1 and S2 that are specimens by performing a test or the like before starting the test. For example, the threshold value F is input by the user via the touch panel of the monitor 30 and is HDD25. Are stored in the threshold file 25a. here,
E1 = 0 <F <E2
The relationship is established. Therefore, in step S74, it is finally determined that the sausage S1 is a non-defective product and the sausage S2 is a defective product. And the curvature inspection about sausage S1, S2 is complete | finished.

  Note that the areas E1, E2 of the recessed regions D1, D2 increase as the degree of curvature of the sausages S1, S2 increases. Accordingly, the areas E1 and E2 of the recessed regions D1 and D2 are indexes indicating the degree of curvature of the sausages S1 and S2. That is, by comparing the areas E1, E2 of the recessed regions D1, D2 with the threshold value F, it is possible to inspect the degree of curvature of the sausages S1, S2 corresponding to the recessed regions D1, D2.

  The results of the curvature inspection in steps S71 to S74 are sent to the distribution mechanism 70. Then, the distribution mechanism 70 distributes the sausage S <b> 2 determined to be defective to the defective product storage conveyor 90. Note that the sausage S1 that is determined to be non-defective in the curvature inspection is distributed to the regular line conveyor 80 only when it is determined to be non-defective in all other inspections other than the curvature inspection. If any of the inspections is determined to be a defective product, the product is distributed to the defective product storage conveyor 90.

[Foreign matter inspection]
The CPU 21 of the control computer 20 reads and executes the foreign substance inspection module stored in the HDD 25 to perform image processing on the X-ray image of the product G generated by the image generation unit 21a, and is included in the product G. Detecting foreign objects. Examples of image processing methods employed in the foreign object inspection include a trace detection method and a binarization detection method. As a result of determination by these methods, if there is even one that is determined to be defective, the product G is determined to be defective.

  In the trace detection method, a threshold value is set in advance along the rough thickness of the product G, and foreign matter is mixed into the product G when there is an area that appears darker than the threshold on the X-ray image of the product G. It is a method to judge that. In this method, it is possible to detect a relatively small foreign object.

  The binarization detection method is a method for determining that a foreign matter is mixed in the product G when there is an area that appears darker than a preset threshold on the X-ray image of the product G. With this method, it is possible to detect a relatively large foreign object.

  In the above method, a mask can be set on the X-ray image. For example, when the product G is packaged in a container, the mask is set for an area corresponding to the container on the X-ray image.

  The threshold value and mask in each method are set and changed by an input from the user using the touch panel function of the monitor 30.

(Crack inspection)
The CPU 21 of the control computer 20 reads and executes the crack inspection module stored in the HDD 25 to perform image processing on the X-ray image of the product G generated by the image generation unit 21a. Detect cracks and cracks. Image processing methods employed for the crack inspection include a pattern matching method and a perimeter measurement method. As a result of determination by these methods, if there is even one that is determined to be defective, the product G is determined to be defective.

  In the pattern matching method, an X-ray image in at least one of a normal state and an abnormal state of the product G is stored in the HDD 25 as a determination criterion in advance, and an X-ray image of the product G is compared with an X-ray image serving as a determination criterion. It is a method.

  The perimeter measurement method is a method of comparing the perimeter of the product G appearing on the X-ray image with the perimeter of the product G in a normal state. The peripheral length of the product G in the normal state is stored in the threshold file 25a of the HDD 25 in advance.

[Quantity inspection]
The CPU 21 of the control computer 20 reads and executes the quantity inspection module stored in the HDD 25, thereby performing image processing on the X-ray image of the product G generated by the image generation unit 21a and including the product G. Check the number of contents to be stored.

  In the quantity inspection, the number of contents of the product G appearing on the X-ray image is counted, and it is determined whether or not the number is normal. The number of contents of the product G in the normal state is stored in the threshold file 25a of the HDD 25 in advance.

(Characteristic)
[1]
In the curvature inspection of the X-ray inspection apparatus 10, the inspection areas B1, B2 occupied by the sausages S1, S2 are extracted from the X-ray images 61 of the sausages S1, S2, and the envelope figures C1, C2 of the extracted inspection areas B1, B2 are extracted. The shapes of the sausages S1 and S2 are inspected based on the derived envelope figures C1 and C2. That is, in the X-ray inspection apparatus 10, the degree of bending of the product G is inspected simply and with high accuracy.

  The curvature inspection of the X-ray inspection apparatus 10 is particularly useful when inspecting the degree of curvature of the elongated product G such as the sausages S1 and S2.

[2]
In the X-ray inspection apparatus 10, it is possible to perform a foreign substance inspection, a cracked chip inspection, a quantity inspection, and the like along with the curvature inspection on the X-ray image generated by the image generation unit 21 a. Therefore, the product G can be inspected from various viewpoints based on one X-ray image 61.

Second Embodiment
Next, an X-ray inspection apparatus 110 according to the second embodiment of the present invention will be described.

  As shown in FIG. 8, the X-ray inspection apparatus 110 according to the second embodiment performs a dent inspection instead of a curvature inspection in the control computer 20 as compared with the X-ray inspection apparatus 10 according to the first embodiment. It is different only in that it is different, and is the same in other points. That is, the X-ray inspection apparatus 110 according to the second embodiment is obtained by replacing the curvature inspection module stored in the hard disk 25 of the control computer 20 of the X-ray inspection apparatus 10 according to the first embodiment with a dent inspection module. is there. Therefore, only the details of the dent inspection according to the second embodiment will be described below, and the other configuration and operation of the X-ray inspection apparatus 110 are the same as those of the first embodiment, and the description thereof will be omitted.

[Indentation inspection]
The CPU 21 of the control computer 20 reads and executes the dent inspection module stored in the HDD 25, thereby operating as an inspection region extraction unit 121b, an envelope graphic derivation unit 121c, a dent region derivation unit 121d, and a comparison unit 121e (FIG. 8). Each of these units 121b to 121e inspects the degree of depression of the product G by performing image processing on the X-ray image of the product G generated by the image generation unit 21a.

  Hereinafter, the details of the dent inspection will be described with reference to FIGS. 9 and 10 by taking the canned T as a sample. In addition, in order to make explanation easy to understand, the canned food T illustrated is a substantially cylindrical can T2 filled with the contents T1, and a part of the side surface of the can T2 is recessed inside. On the X-ray image 161 shown in FIG. 9A, a region I1 that appears dark and substantially circular at the center indicates the contents T1 of the canned T, surrounds the region I1, and is darker than the region I1 in a ring shape. A region I2 appearing in FIG. 2 shows the can T2 of the can T. Of the region I2, a region I3 surrounded by a dotted line in FIG. 9A indicates a dent formed in the can T2.

  First, in step S171, the inspection region extraction unit 121b performs binarization processing on the region on the X-ray image 161, the region J1 indicating the contents T1 of the canned T, and the can T2 of the canned T or the background of the canned T. Into the area J2 indicating. Note that the X-ray image 161 to be binarized in step S171 is generated by the image generating unit 21a.

  In the binarization process, it is determined whether or not the value of the amount of X-ray transmission corresponding to each pixel constituting the X-ray image 161 is between two predetermined threshold values. Then, according to the determination result, either “0” or “1” is assigned to each pixel. “0” indicates a region corresponding to the contents T1 of the canned T, and “1” indicates a region corresponding to the can T2 of the canned T or the background of the canned T. Here, the two threshold values used for the binarization processing are appropriately determined in advance according to the canned sample T by performing a test or the like before starting the inspection. It is assumed that the data is stored in the threshold file 25a of the HDD 25 by the user.

  An image 162 illustrated in FIG. 9B is an image after the binarization process is performed on the X-ray image 161. On the image 162, a region J1 appearing white in the center corresponds to the contents T1 of the canned T, and other regions J2 appearing black correspond to the can T2 of the canned T or the background of the canned T. That is, in step S171, the region J1 corresponding to the contents T1 of the canned T packed in the can T2 of the canned T is extracted from the X-ray image 161. Hereinafter, the region J1 extracted as the region corresponding to the contents T1 of the canned T in step S171 is referred to as an inspection region J1.

  Next, in step S172, the envelope graphic deriving unit 121c derives the envelope graphic K1 (see FIG. 9C) of the inspection region J1 corresponding to the contents T1 of the canned T extracted in step S171. In addition, the envelope figure of a certain area means a figure that includes the entire area and has the smallest area among figures that are expressed only by a convex line on the outer periphery. In other words, the envelope figure of a certain area refers to a figure surrounded by a rubber band applied along the cross section of an object whose cross section has the same shape as that area. Further, the convex line means a line in which a line segment connecting any two points in a region surrounded by the line is always included in the region.

  The envelope figure K1 of the inspection area J1 on the image 162 shown in FIG. 9B appears in a white and substantially circular shape at the center on the image 163 shown in FIG. 9C. The inspection area J1 corresponding to the contents T1 of the canned T has a shape in which a part of the outer periphery of a substantially circular shape is recessed inward, whereas the envelope figure K1 is the corresponding area of the inspection area J1. It has a shape in which a dent is filled in by drawing a string in the dent. That is, the envelope figure of the inspection area corresponding to the contents packed in the can recessed inside has a larger area than the original inspection area.

  Next, in step S173, the recessed area deriving unit 121d derives the recessed area L1 (see FIG. 9D) included in the envelope figure K1 derived in step S172. A dent area | region means the area | region which deducted the test | inspection area | region extracted by step S171 from the envelope figure derived | led-out by step S172.

Next, in step S174, the comparison unit 121e calculates the area M1 of the recessed area L1 derived in step S173, and compares the area M1 with a preset threshold value N. As a result of the comparison, if the area M1 of the recessed region L1 is equal to or less than the threshold value N, the canned product T is determined as a non-defective product, and if it is larger than the threshold value N, the canned product T is determined as a defective product. The threshold value N is appropriately determined in advance according to the canned sample T by performing a test or the like before starting the test. For example, the threshold value N is input by the user via the touch panel of the monitor 30 and the threshold value of the HDD 25 is set. It is assumed that it is stored in the file 25a. Here, tentatively
N <M1
This relationship is established. In this case, in step S174, the canned product T is finally determined to be a defective product. And the dent inspection about canned T is complete | finished.

  In addition, the area M1 of the dent area | region L1 becomes large as the degree of the dent to the inner side of the can T2 of the can T increases. Therefore, the area M1 of the dent region L1 is an index indicating the degree of dent in the can T2 inside the can T. That is, by comparing the area M1 of the dent region L1 with the threshold value N, it is possible to inspect the degree of dent in the can T2 inside the can T2.

  The result of the dent inspection in steps S171 to S174 is sent to the distribution mechanism 70. Then, the distribution mechanism 70 distributes the canned goods T determined to be defective products to the defective product storage conveyor 90.

(Characteristic)
In the dent inspection of the X-ray inspection apparatus 110, the inspection region J1 occupied by the contents T1 of the canned T surrounded by the can T2 of the canned T is extracted from the X-ray image 161 of the canned T, and the envelope figure of the extracted inspection region J1 is extracted. K1 is derived, and the shape of the can T2 of the can T is inspected based on the derived envelope graphic K1. That is, the X-ray inspection apparatus 110 can easily and accurately inspect the abnormality of the degree of the dent of the product G.

  Note that the dent inspection of the X-ray inspection apparatus 110 is particularly useful when inspecting the dent toward the inner space side of a container having an inner space such as the canned T.

<Modification>
Although the first embodiment and the second embodiment of the present invention have been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

(A)
In the above embodiment, in order to extract the inspection areas B1, B2, J1 from the X-ray images 61, 161, the areas on the X-ray images 61, 161 are the inspection areas B1, B2, J1 and the other areas B3, J2. A binarization process is used. However, other image processing can be adopted instead of or in addition to the binarization processing.

(B)
In the above embodiment, the threshold value used for the binarization process and the inspection parameters such as the threshold values F and N used in steps S74 and S174 are manually input by the user via the touch panel of the monitor 30. This may be configured to be automatically input.

  For example, by flowing sausage at the boundary between a non-defective product and a defective product to the X-ray inspection apparatus 10, the area of the recessed region corresponding to the sausage is automatically calculated from the obtained X-ray image, and the area is set as the threshold value F. It may be set automatically. Sausage at the boundary between good and defective products is a sausage that is a criterion for determining whether the product is good or defective, and sausage that is straighter than the sausage is treated as a good product and curved more than the sausage. Will be handled as defective.

  Thereby, the trouble of manual input by the user can be saved.

(C)
In the above embodiment, various inspections by the control computer 20 are realized by the CPU 21 executing the inspection program stored in the HDD 25. However, various inspections may be realized by other software, hardware, or any combination thereof.

  In addition, the processing relating to the inspection region extraction units 21b and 121b, the envelope figure deriving units 21c and 121c, the recessed region deriving units 21d and 121d, and the comparison units 21e and 121e is an apparatus provided separately from the X-ray inspection apparatuses 10 and 110. It may be executed in the above. For example, the X-ray images 61 and 161 obtained by the image generation unit 21a are sent to a separate computer via a network or a storage medium that can be inserted into the drive 104, and based on the sent X-ray images 61 and 161. The above processing may be executed in the computer.

(D)
In the first embodiment, after step S72, the following processing may be executed instead of step S73 and step S74.

  That is, the area of each envelope figure C1, C2 derived in step S72 is compared with a preset threshold value. As a result of the comparison, if the areas of the envelope figures C1 and C2 are equal to or smaller than the threshold value, the sausages S1 and S2 are determined to be non-defective products, and if they are larger than the threshold value, the sausages S1 and S2 are determined to be defective products. It may be.

  In this case, it is not necessary to derive the recessed areas D1 and D2, and the process for the curvature inspection is simplified.

  This modification can also be applied to the second embodiment.

(E)
The dent inspection disclosed in the second embodiment is also useful for a can that is not filled with contents, that is, an empty can. In this case, in step S171, a region corresponding to the cavity surrounded by the can is extracted from the X-ray image as an inspection region.

(F)
The X-ray inspection apparatus 10 according to the first embodiment may include the dent inspection module according to the second embodiment. That is, the X-ray inspection apparatus 110 according to the second embodiment may include the curvature inspection module according to the first embodiment.

  INDUSTRIAL APPLICABILITY The present invention has an effect that an abnormality in the shape of an article can be easily and accurately inspected, and is useful as an X-ray inspection apparatus and an inspection method for inspecting the shape of an article using X-rays.

1 is an external perspective view of an X-ray inspection apparatus according to a first embodiment of the present invention. The block diagram inside the shield box of a X-ray inspection apparatus. The schematic diagram which shows the principle of a X-ray inspection. The block diagram before and behind an X-ray inspection apparatus. The block block diagram of the control computer concerning 1st Embodiment of this invention. (A) The figure which shows the X-ray image of a sausage. (B) The figure which shows the image after performing the binarization process to the X-ray image shown to (a). (C) The figure which shows the envelope figure of the test | inspection area | region contained in the image shown to (b). (D) The figure which shows the dent area | region contained in the image shown to (c). The flowchart which shows the process of the curvature test | inspection concerning 1st Embodiment of this invention. The block block diagram of the control computer concerning 2nd Embodiment of this invention. (A) The figure which shows the X-ray image of canned food. (B) The figure which shows the image after performing the binarization process to the X-ray image shown to (a). (C) The figure which shows the envelope figure of the test | inspection area | region contained in the image shown to (b). (D) The figure which shows the dent area | region contained in the image shown to (c). The flowchart which shows the process of a dent test | inspection concerning 2nd Embodiment of this invention.

Explanation of symbols

10,110 X-ray inspection device 13 X-ray irradiator (irradiation unit)
14 X-ray line sensor (light receiving part)
21a Image generation unit (generation unit)
21b, 121b Inspection region extraction unit (extraction unit)
21c, 121c Envelope figure derivation unit (derivation unit)
21d, 121d Depression region derivation part (inspection part)
21e, 121e Comparison part (inspection part)
61,161 X-ray image B1, B2 Inspection area C1, C2 Envelope figure D1, D2 Depression area E1, E2 Depression area area F Threshold G Product J1 Inspection area K1 Envelope figure L1 Depression area M1 Depression area area N Threshold value S1 Good Sausages (articles)
S2 Defective sausage (article)
T Canned T1 Canned contents T2 Canned can (article)

Claims (7)

An irradiation unit for irradiating the article with X-rays;
A light receiving unit for receiving X-rays from the irradiation unit;
A generator that generates an X-ray image based on the X-rays received by the light receiver;
An extraction unit that extracts an inspection region that is a region corresponding to the article from the X-ray image;
A derivation unit for deriving an envelope figure that includes the entire inspection region and has a minimum area among figures that are expressed only by convex lines on the outer periphery;
An inspection unit that inspects the shape of the article based on the envelope figure;
Comprising
X-ray inspection equipment. An irradiation unit for irradiating the article with X-rays;
A light receiving unit for receiving X-rays from the irradiation unit;
A generator that generates an X-ray image based on the X-rays received by the light receiver;
An extraction unit that extracts an inspection area that is an area corresponding to another article or space surrounded by the article from the X-ray image;
A derivation unit for deriving an envelope figure that includes the entire inspection region and has a minimum area among figures that are expressed only by convex lines on the outer periphery;
An inspection unit that inspects the shape of the article based on the envelope figure;
Comprising
X-ray inspection equipment. The inspection unit derives a recessed area that is an area obtained by subtracting the inspection area from the envelope figure, and inspects the shape of the article by comparing the area of the recessed area with a predetermined threshold value.
The X-ray inspection apparatus according to claim 1 or 2. The article has an elongated shape;
The inspection unit inspects the degree of curvature of the article;
The X-ray inspection apparatus according to claim 1. The article is a container having an internal space;
The inspection unit inspects the degree of depression of the article.
The X-ray inspection apparatus according to claim 2. An extraction step of extracting an inspection area, which is an area corresponding to the article, from an X-ray image of the article;
A derivation step of deriving an envelope figure that is a figure that has the smallest area among figures that include the entire inspection area and that is represented only by a convex line on the outer periphery;
An inspection step of inspecting the shape of the article based on the envelope figure;
Comprising
Inspection method. An extraction step of extracting an inspection area, which is an area corresponding to another article or space surrounded by the article, from an X-ray image of the article;
A derivation step of deriving an envelope figure that is a figure that has the smallest area among figures that include the entire inspection area and that is represented only by a convex line on the outer periphery;
An inspection step of inspecting the shape of the article based on the envelope figure;
Comprising
Inspection method.

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