JP2005003480A - X-ray examination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray examination apparatus capable of properly examining a subject even if the position or posture of the subject, which passes through the space between an X-ray irradiator and an X-ray line sensor, is shifted. <P>SOLUTION: The X-ray examination apparatus is equipped with the X-ray irradiator, the X-ray line sensor, an image processing routine and an examination deciding and processing routine. The X-ray line sensor detects the X rays from the X-ray irradiator. In the image processing routine, a raw image due to X rays is subjected to image processing to form a processed image while the subject is examined on the basis of the processed image in the examination deciding and processing routine. Further, in the image processing routine, a processed image is formed through a process for extracting the boundary lines S11-S14 of the subject and a background (the outside part of the subject) from the raw image. In the examination deciding and processing routine, the inside region of the boundary lines S11-S14 of the processed image is set as a target to perform examination. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray inspection apparatus, and more particularly to an X-ray inspection apparatus that performs image processing to inspect a specimen that passes between an X-ray source and an X-ray light receiving unit.
[0002]
[Prior art]
In the production line of commodities such as foods, an inspection may be performed by an X-ray inspection apparatus in order to prevent shipment of such commodities when foreign matters are mixed into the commodities or the products are cracked. In this X-ray inspection apparatus, X-rays are radiated from an X-ray source to a specimen (product) that is continuously conveyed, and the X-ray transmission state is detected by an X-ray light receiving unit. It is determined whether there is no contamination, whether the specimen is cracked or missing, and the quantity of unit contents in the specimen is insufficient. In addition, the X-ray inspection apparatus may perform an inspection for counting the number of unit contents in the specimen.
[0003]
As such an X-ray inspection apparatus, for example, an apparatus shown in Patent Document 1 has been proposed.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-228761
[0005]
[Problems to be solved by the invention]
By the way, in a conventional X-ray inspection apparatus, when an area to be inspected is specified from an X-ray image, the area to be inspected is often determined by applying a mask to a predetermined area. The predetermined area to be masked is a fixed area that is set in advance and is set as an area having a thickness of a predetermined dimension from the edge of the image, or is set with XY coordinates from the top of the sample transported by the sensor. To do.
[0006]
However, if the predetermined area is fixed in advance as described above, the mask is originally applied when the specimen is transported while being shifted in the width direction or when the transport posture of the specimen is shifted and inclined. There is a risk of masking a portion that is not an ideal region. In such a case, the specimen may not be properly tested. An object of the present invention is to provide an X-ray inspection apparatus capable of appropriately inspecting a specimen even when the position and posture of the specimen passing between the X-ray source and the X-ray light receiving unit are shifted. .
[0007]
[Means for Solving the Problems]
An X-ray inspection apparatus according to a first aspect includes an X-ray source that emits X-rays, an X-ray light receiving unit, an image processing unit, and an inspection unit. The X-ray light receiving unit receives X-rays from the X-ray source. The image processing unit creates a processed image by performing image processing on the raw image of the X-ray received by the X-ray light receiving unit. The inspection unit inspects the specimen passing between the X-ray source and the X-ray light receiving unit based on the processed image. In addition, the image processing unit creates a processed image through a process of extracting a boundary between the specimen and the background (portion outside the specimen) from the raw image. Then, the inspection unit performs an inspection on the inner region of the boundary of the processed image. The inspection includes inspection of whether or not a foreign substance is mixed in the specimen and inspection of the quantity of unit contents contained in the specimen.
[0008]
Here, X-rays from the X-ray source pass through the specimen when the specimen is present, and directly reach the X-ray light receiving unit otherwise. Based on the processed image obtained by image processing of the raw image by X-ray, the inspection unit has no foreign matter mixed in the specimen, the specimen shape is not abnormal, or the quantity of unit contents in the specimen is Check for normality.
[0009]
Here, in the creation of the processed image by the image processing unit, the boundary between the specimen and the background is extracted, and the inspection unit performs an inspection on the inner region of the boundary. For this reason, even when the position or posture of the specimen passing between the X-ray source and the X-ray light receiving unit is deviated, the part that requires examination of the specimen surely enters the region to be examined, and the specimen Inspected properly.
[0010]
An X-ray inspection apparatus according to a second aspect is the X-ray inspection apparatus according to the first aspect, wherein the specimen is composed of a package and contents in the package. Further, the specimen receives X-rays during transportation. The light receiving unit is an X-ray line sensor, and a plurality of elements extend in a second direction substantially orthogonal to a first direction that is a sample transport direction. The plurality of elements of the X-ray line sensor receive X-rays irradiated radially from the X-ray source. The X-ray inspection apparatus according to claim 2 further includes a mask region setting unit. The mask area setting unit can set the first mask area and the second mask area separately. The first mask region is a mask region set for the vicinity of the first portion of the boundary located at both ends in the first direction of the processed image. The second mask area is a mask area set for the vicinity of the second portion of the boundary located at both ends of the processed image in the second direction. In addition, the inspection unit performs an inspection on a region where the first and second mask regions are removed from the inner region of the boundary of the processed image.
[0011]
Here, the contents are in the package, and the boundary in the extracted processed image is the boundary separating the inside and the outside of the package. On the other hand, in the X-ray line sensor, a plurality of elements extend in a second direction substantially orthogonal to the first direction, which is the direction in which the specimen is transported, and the X-ray source projects X-rays radially to these elements. To do. That is, X-rays are irradiated in a fan shape around the X-ray source to a plurality of elements arranged on a straight line.
[0012]
Therefore, at the front and rear ends of the package in the transport direction, even if the first portion that is the boundary is relatively thin and appears in the processed image, the X-ray strikes obliquely at the two ends in the second direction of the package and two or more elements It is assumed that the X-ray shielding is performed, and the second part that is the boundary appears relatively thick in the processed image.
On the other hand, in the apparatus of claim 2, the mask region setting unit includes a first mask region set for the vicinity of the first portion, and a second mask region set for the vicinity of the second portion. Can be set separately. For this reason, it is possible to set the mask region in consideration of the difference in the required mask region at each part of the boundary caused by X-ray irradiation being performed radially to the X-ray line sensor extending from the X-ray source. it can. As a result, the package portion can be appropriately set as the mask area in the processed image as compared with the case where the mask area is uniformly set by a predetermined amount from the boundary.
[0013]
For example, when X-ray irradiation is performed in a fan shape from an X-ray source located above a box containing goods to be conveyed to an X-ray line sensor located below the box, the X-ray irradiated in a fan shape Is received by a long X-ray line sensor, it is assumed that the X-ray hits the side of the box obliquely near both ends of the X-ray line sensor, and the left and right side faces appear thicker than the front and rear side faces of the box in the processed image. The However, here, while setting a large second mask area for the boundary portion (second portion) of the left and right side surfaces of the box that appears thick in the processed image, the boundary portion (first portion) of the front and rear sides of the box that appears thinly ), A small first mask region can be set.
[0014]
An X-ray inspection apparatus according to a third aspect is the X-ray inspection apparatus according to the first aspect, further comprising a mask region setting unit. The mask area setting unit sets a mask area for the vicinity of the boundary of the processed image. Then, the inspection unit performs an inspection on the inner region of the boundary of the processed image excluding the mask region.
Here, the boundary between the specimen and the background is extracted and the inner area of the boundary is set as the inspection target, and the mask area is set near the boundary to exclude the mask area from the inspection target. As a result, even when the specimen is the box and the product or container contained in the box and the contents contained in the container, only the product in the box or the contents in the container can be set as the inspection target.
[0015]
The X-ray inspection apparatus according to claim 4 is the X-ray inspection apparatus according to claim 3, wherein the mask region setting unit stores at least a predetermined shape of the specimen and corresponds to the predetermined shape A part to be processed is found from the processed image, and a mask area is set with the part as a reference.
Here, with respect to the vicinity of the boundary of the processed image, the mask region is set with reference to a portion corresponding to a predetermined shape of the specimen on the processed image. By setting the mask area in this way, when the sample is a box, the product or container contained in the box, and the contents contained in the container, the mask area is set near the boundary to set the box or container. In addition to being able to be removed from the inspection target, even if the product is misaligned in the box or the contents are misaligned in the container, the mask area is set based on the part corresponding to the predetermined shape of the product and contents The inspection object can be determined in an appropriate area on the processed image.
[0016]
For example, if the product in which the tube containing toothpaste is in the box is a specimen, the box area and the empty space in the box can be set as the mask area, and the mask area based on the cap part of the tube with a specific shape When the position of the tube in the box is misaligned, only the inside of the tube can be appropriately determined as the inspection target area on the processed image.
[0017]
An X-ray inspection apparatus according to a fifth aspect is the X-ray inspection apparatus according to the third aspect, wherein the mask region setting unit separately provides a mask region for the vicinity of a plurality of portions at the boundary of the processed image. Set. Then, the inspection unit performs an inspection on a region inside the boundary of the processed image from which the plurality of mask regions are removed.
Here, in the processed image from which the boundary is extracted, different mask regions can be set in the vicinity of a plurality of portions on the boundary. For this reason, when inspecting products contained in containers whose surroundings have different thicknesses, only the portion of the container can be appropriately set as a mask area, or a box for storing products on a processed image When the four sides appear at different thicknesses, only the box portion can be appropriately set as the mask area.
[0018]
An X-ray inspection apparatus according to a sixth aspect is the X-ray inspection apparatus according to the fifth aspect, wherein the specimen is a box having a plurality of sides and contents stored in the box. A plurality of portions at the boundary of the processed image respectively correspond to the sides of the box.
If the box containing the contents is a sample together with the contents, and you want to inspect only the contents, set the box of the processed image as a mask area and remove it from the area to be inspected. There is a request to do. Then, the sides of the box may have different thicknesses on the processed image depending on how the X-rays are hit, or the physical thickness of each side (each side surface, etc.) of the box may be different from the beginning.
[0019]
Here, a plurality of portions at the boundary of the processed image respectively correspond to the sides of the box, and different mask areas can be set. For this reason, mask regions having different thicknesses can be set for the respective sides of the box, and it is possible to appropriately cope with cases where the thicknesses of the respective sides of the box are different on the processed image.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
An appearance of an X-ray inspection apparatus according to an embodiment of the present invention is shown in FIG. This X-ray inspection apparatus 10 is one of the apparatuses that perform quality inspection in the production line of products such as foods. The X-ray inspection apparatus 10 transmits X-rays to the products that are continuously conveyed and transmits the products. It is a device that determines the defect of goods based on the X-ray dose.
[0021]
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 determined by the X-ray inspection apparatus 10 for the presence or absence of contamination. The determination result in 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.
[0022]
<Configuration of X-ray inspection apparatus>
As shown in FIGS. 1 and 2, the X-ray inspection apparatus 10 mainly includes a shield box 11, a conveyor 12, an X-ray irradiator (X-ray source) 13, and an X-ray line sensor (X-ray light receiving unit). 14, an LCD monitor 30 with a touch panel function, and a control computer 20 (see FIG. 5).
[0023]
[Shield box]
The shield box 11 has an opening 11a for carrying in / out a product on both side surfaces. In this 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.
Although not shown in FIG. 1, the opening 11 a is closed with a shielding nore for suppressing leakage of X-rays to the outside of the shielding box 11. This shielding nolen is formed from rubber containing lead, and is pushed away by the product when the product is carried in and out.
[0024]
In addition to the LCD monitor 30, a key insertion slot and a power switch are arranged on the upper front portion of the shield box 11.
〔Conveyor〕
The conveyor 12 conveys goods in the shield box 11, and is driven by a conveyor motor 12a shown in FIG. The conveying speed by the conveyor 12 is finely controlled by the inverter control of the conveyor motor 12a by the control computer 20.
[0025]
[X-ray irradiator]
As shown in FIG. 2, the X-ray irradiator 13 is disposed above the conveyor 12 and radiates fan-shaped X-rays (see the hatched area X in FIG. 2) toward the lower X-ray line sensor 14. To do. That is, the X-ray irradiator 13 emits X-rays radially downward.
[0026]
[X-ray line sensor]
The X-ray line sensor 14 is disposed below the conveyor 12 and detects X-rays that pass through the product G and the conveyor 12. As shown in FIG. 3, the X-ray line sensor 14 includes a large number of pixels 14 a that are horizontally arranged in a straight line in a direction orthogonal to the conveying direction by the conveyor 12.
[0027]
[LCD monitor]
The LCD monitor 30 is a full-dot liquid crystal display and also has a touch panel function. The LCD monitor 30 displays an inspection result screen during operation, and also displays a screen for prompting parameter input for initial setting and defect determination.
[0028]
[Control computer]
As shown in FIG. 5, the control computer 20 includes a CPU 21, and a ROM 22, a RAM 23, and an HDD (hard disk) 25 as a main storage unit controlled by the CPU 21. The HDD 25 stores a threshold file 25a, a mask area information file 25b, and the like. The control computer 20 also has an FDD (flexible disk drive) 24 that performs input / output with the flexible disk.
[0029]
Further, the control computer 20 includes a display control circuit that controls data display on the LCD monitor 30, a key input circuit that captures key input data from the touch panel of the LCD monitor 30, an I for controlling data printing in a printer (not shown), and the like. / O port etc.
The CPU 21, ROM 22, RAM 23, FDD 24, HDD 25, and the like are connected to each other via a bus line such as an address bus or a data bus.
[0030]
The control computer 20 is connected to a conveyor motor 12a, a rotary encoder 12b, a photoelectric sensor 15, an X-ray irradiator 13, an X-ray line sensor 14, and the like.
The rotary encoder 12b is attached to the conveyor motor 12a, detects the conveyance speed of the conveyor 12, and sends it to the control computer 20.
[0031]
The photoelectric sensor 15 is a synchronization sensor for detecting the timing at which the product as a sample comes to the position of the X-ray line sensor 14, and is composed of a pair of light projectors and light receivers arranged with a conveyor interposed therebetween.
<Determination of product defects by control computer>
[Create X-ray image]
The image processing routine 28 executed by the CPU 21 of the control computer 20 receives a signal from the photoelectric sensor 15 and when the product G passes through the fan-shaped X-ray irradiation unit (see FIG. 2), the X-ray line sensor 14. X-ray fluoroscopic image signals (see FIG. 3) obtained by the above are acquired at fine time intervals, and an X-ray image (raw image) of the product G is created based on these X-ray fluoroscopic image signals. The X-ray images are images 41 and 51 as shown in FIGS. 9A and 17A.
[0032]
[Product defect judgment]
Then, the inspection determination processing routine 29 of the control computer 20 determines whether the product is good or bad from the obtained X-ray image by three determination methods. The three determination methods are a trace detection method, a binarization detection method, and a mask binarization detection method.
Of these determination methods, the trace detection method and the binarization detection method make a determination on an unmasked region of an image. On the other hand, in the mask binarization method, a determination is made on a masked area of an image. The mask is set for the container portion of the product. In the binarization detection method and the mask binarization method, the obtained X-ray image is binarized to create a processed image, and the processed image is used to determine whether the product is good or bad.
[0033]
In the trace detection method, a reference level (threshold value) is set along the rough thickness of the object to be detected, and it is determined that foreign matter is mixed in the product G when the image becomes darker than that. It is a method. Here, two trace reference levels are set, and each is compared with an image for determination. The first trace reference level is relatively fine and is set to detect foreign matter of 2 mm or less. The second trace reference level is set to detect a foreign matter of 2 to 4 mm.
[0034]
Specifically, the trace reference level of the trace detection method is set as shown in FIG. Setting this trace reference level higher increases the detection sensitivity, but setting it too high makes it easy to misjudg normal products as foreign-contaminated products, so it is appropriate for the size of the foreign matter to be detected. Must be set to
The binarization detection method and the mask binarization method are methods in which a reference level is set to a constant brightness and it is determined that a foreign object is mixed in the product when the image becomes darker than that. This binarization detection method is set to detect a large foreign object of about 4 mm or more. In the binarization detection method and the mask binarization method, different reference levels are set.
[0035]
Specifically, the reference level of the binarization detection method is set as shown in FIG. Setting this reference level higher increases detection sensitivity, but setting it too high makes it easy to misjudg normal products as foreign-contaminated products. Must be set.
The mask in the mask binarization method is set as shown in FIG. In this mask, as described above, the container portion of the product is set as the insensitive area. The set values are basically the number of contractions and the number of expansions. If the brighter part than the effective level of the image is the “background area” and the dark part is the “specimen area”, the mask area is an area that enters the specimen area by the number of expansion pixels from the boundary between the two areas. If there is a background area between the container part and the contents of the product, and the mask area is also applied to the contents when the container is masked, the background area is temporarily reduced by the number of reduction pixels and the container and the contents are The number of expansions is set after eliminating the intervening background area (see FIG. 8), or, as will be described later, other than the outermost background area is combined with the specimen area as not being the background area.
[0036]
Note that the reference level in each of the above determination methods is stored in the threshold file 25a created in the HDD 25. The threshold file 25a stores a reference level for each determination method for each type of product. The number of expansions for determining the mask area is stored in the mask area information file 25b in the HDD 25 for each type of product. These reference levels and the number of expansions can be set and changed by input from the touch panel of the LCD monitor 30 during a test operation or a test operation during normal operation.
[0037]
<Details of mask binarization method>
[Inspection by setting mask area using multiple expansion times]
As shown in FIG. 8, the mask area set as the insensitive area is an area that enters the specimen area by the number of times of expansion from the boundary between the background area and the specimen area. For a normal product, basically only one expansion number is set. That is, in the case of a product composed of a container and contents as shown in FIG. 8, dark portions that may be mistaken for foreign matters appear in the image in the container portion. It is assumed that there is a mask area by using the same number of expansions at both ends of the container. For example, in the case of expansion of a white region, the expansion of a region is a process of making a peripheral pixel white when a certain pixel of interest is white.
[0038]
In addition to products for which the number of expansions may be set uniformly, there are products for which a mask area cannot be set appropriately if the number of expansions is set uniformly among many products. In addition, when a product containing contents in a container or box is transported in an oblique orientation on a plane, the part that needs to be inspected can be appropriately selected by simply setting the number of expansions uniformly. There is a risk that it cannot be inspected. In particular, when the container or box is not circular but rectangular in plan, a further device for image processing is required. In view of this, here, image processing and mask area setting as described below are performed so that a product having a package such as a container or a box is appropriately inspected.
[0039]
An image 41 shown in FIG. 9A is an X-ray image of a product in which the toothpaste-containing tube T enters the box BX1. In the case of such a product, the sides BS11 to BS14 of the box BX1 appearing on the image, the space between the sides BS11 to BS14 and the tube T, the cap portion T1 of the tube T and the folded portion T2 at the lower end are foreign matter. It is easy to be mistaken. Therefore, these are set as mask areas.
[0040]
First, in the image processing routine 28 executed by the CPU 21 of the control computer 20, the image 41 in FIG. 9A is divided into background areas W1, W2, W3, W4 and a sample area by binarization. In FIG. 9B, the white areas are the background areas W1, W2, W3, W4, and the black areas are the sample areas.
In order to remove the areas W2, W3, and W4 that are distinguished from the background area because the processing image 42 shown in FIG. 9B that has been binarized in this manner is bright despite being inside the box BX1. The image processing routine 28 of the control computer 20 takes out the outermost one (background area W1) from the background areas W1, W2, W3, and W4, and uses the areas W2, W3, and W4 other than the background area W1 as background areas. Recognize not. In this way, the image processing routine 28 of the control computer 20 creates the image 43 divided into the background area W1 and the other sample areas as shown in FIG.
[0041]
In the image 43, the boundary between the background area W1 and the specimen area clearly appears as four boundary lines S11 to S14. These boundary lines S11 to S14 correspond to the sides BS11 to BS14 of the product box BX1 which is the sample. Therefore, the sample area excluding the background area W1 in the image 43 includes the sides BS11 to BS14 of the box BX1, the space between the sides BS11 to BS14 and the tube T, and the cap portion T1 of the tube T and the folded portion T2 at the lower end. Includes the part you want to make the mask area.
[0042]
The image processing routine 28 of the control computer 20 adds a mask area to a portion desired to be a mask area by a method shown in FIG. 10B by a mask area setting processing subroutine 28a. That is, the boundary line S11 located on the left side of FIG. 10 enters the inside (right side) with a predetermined number of expansions (see the white arrow A1) to create a new boundary line S21, and the boundary line located on the right side of FIG. S12 is made to enter the inside (left side) at a predetermined number of expansions (see white arrow A2) to create a new boundary line S22, and the boundary line S13 located on the upper side of FIG. ) (See the white arrow A3), a new boundary line S23 is created, and the boundary line S14 located on the lower side of FIG. 10 enters the inner side (upper side) with a predetermined number of expansions (white arrow A4). Reference) Create a new boundary line S24. Accordingly, an additional left mask area W51, an additional right mask area W52, an additional upper mask area W53, and an additional lower mask area W54 are newly set in the portion that has been the specimen area. In this way, the additional mask areas W51 to W54 are added to the background area W1, and the background area W1 expands inward to create a new mask area W7 (see FIG. 11). The white portions in the image 44 shown in FIG. 11 include the sides BS11 to BS14 of the box BX1, the space between the sides BS11 to BS14 and the tube T, and the cap portion T1 of the tube T and the folded portion T2 at the lower end. This is the final mask area W7. A black portion in the image 44 shown in FIG. 11 is an inspection target area W6 that covers the inside of the tube T.
[0043]
As apparent from FIG. 10B, the number of expansions for creating a new boundary line S21 from the boundary line S11, the number of expansions for creating a new boundary line S22 from the boundary line S12, and the boundary line S13. The number of expansions for creating a new boundary line S23 and the number of expansions for creating a new boundary line S24 from the boundary line S14 are set separately. That is, the number of expansions for each of the boundary lines S11 to S14 is not set uniformly, but is set separately. These settings are made by the operator while viewing the screen during a test run or the like. Specifically, the setting of the number of expansions of the top, bottom, left, and right is set for each product (or each product) at the time of a trial run or the like, but it is also possible to make adjustments while inspecting. The four expansion times set here are stored in the mask area information file 25b in the HDD 25 for each product (or each product type).
[0044]
The mask area W7 of the processed image 44 created by the image processing routine 28 of the control computer 20 in this way is used as follows in the determination of the contamination of the tube T in the inspection determination processing routine 29 of the control computer 20. It is done.
In FIG. 12A, for easy understanding, boundary lines S21 to S24 between the mask area W7 and the inspection target area W6 with respect to the X-ray image of the boxed product in which foreign matter is mixed in the tube T. Are piled up. The image processing routine 28 of the control computer 20 instantaneously performs the above-described image processing (creation of processed images 42, 43, 44) on the X-ray raw image 41, and recognizes an appropriate mask area W7 in the image 41. To do. Then, the control computer 20 erases the foreign matter in the mask area W7 among the foreign matters detected in the image 41. Thus, for example, even when a foreign object is detected in the mask area W7 due to erroneous detection as shown in FIG. 12A, the shadow is erased from the image 41, and finally FIG. 12B. An image 45 showing only the foreign matter in the tube T as shown in FIG. In this way, the inspection determination processing routine 29 of the control computer 20 determines the presence of foreign matter in the tube T.
[0045]
[When products are placed diagonally on the conveyor]
Next, the mask area W7 and the inspection target area W6 when the product in which the tube containing toothpaste enters the box is placed on the conveyor 12 in an oblique state not along any side surface (side) with respect to the transport direction. Generation will be described.
As shown in FIG. 13A, even if the product is in an oblique state, boundary lines S11 to S14 between the background area W1 and the sample area are detected and set based on the boundary lines S11 to S14. Depending on the number of expansions, the additional mask areas W51 to W54 and the boundary lines S21 to S24 between the mask area W7 and the inspection target area W6 are determined. And as shown in FIG.13 (b), the mask area W7 and the test object area W6 are determined in the form corresponding to the diagonal state of goods.
[0046]
Therefore, if the foreign matter in the mask area W7 shown in FIG. 13B is removed from the foreign matter detected in the X-ray image of the oblique product, an image showing only the foreign matter in the tube that needs to be inspected is generated. Is done.
[When the contents (tube) move in the box]
Next, the adjustment process in the production | generation of the mask area with respect to the goods which the toothpaste tube T may move in a box is demonstrated.
[0047]
When the tube T moves in the box, as shown in FIGS. 14 (a) and 14 (b), the mask area can be appropriately set by using only the four expansion times determined in advance, up, down, left and right. It may not be generated. In FIG. 14A, the boundary lines S21 to S24 of the mask area are at appropriate positions. However, when the tube T moves in the box, the boundary lines S21 to S24 of the mask area are changed as shown in FIG. The proper position is not reached, and a part T10 in the tube T is included in the mask area, or a portion T20 outside the tube T to be masked comes out of the mask area.
[0048]
In order to cope with such a situation, here, for a product in which the tube T moves in the box, the characteristic shape of the tube T is stored, and the portion corresponding to the shape is binary. The number of expansions is adjusted by detecting from the image 42 after the conversion processing. Specifically, the external shape in the vicinity of the cap of the tube T is stored in the HDD 25, and a shape C (see FIG. 15) that matches the external shape is detected from the image 42, and the shape in the region inside the boundary lines S11 to S14. The number of expansions is adjusted according to the position of C. Thereby, even when the tube T moves in the box, the number of expansions is corrected accordingly, and an appropriate mask area is generated in a portion other than the inside of the tube T.
[0049]
It should be noted that the characteristic shape of the tube T (outer shape in the vicinity of the cap) is not detected from the binarized image 42, but the cap shading pattern is detected from the raw X-ray image (gray image). It is also possible to make it.
[When the inside of a tall box is used as an inspection area]
Next, as shown in FIG. 16, the products that are carried on the conveyor 12 are the box BX2 and the contents U (see FIG. 17A) in the box BX2, and the height of the box BX2 is A method for appropriately determining the inspection target area from the X-ray image when it is relatively large will be described. Using this method, the operator sets the number of left and right and up and down expansions during a test run so that an appropriate inspection target area is generated.
[0050]
In the present apparatus 10, as shown in FIG. 2, X-rays are irradiated in a fan shape from the X-ray irradiator 13 above the conveyor 12 toward the X-ray line sensor 14 below the conveyor 12. Therefore, as shown in FIG. 16, X-rays strike diagonally on both side surfaces BS21 and BS22 of the box BX2 in the direction in which the X-ray line sensor 14 extends. For this reason, particularly when the height of the box BX2 is large, the shadows of the side surfaces BS21 and BS22 are reflected on the two or more pixels 14a of the X-ray line sensor 14. That is, if X-rays are irradiated vertically downward from directly above, the shadows of the side surfaces BS21 and BS22 are reflected only on one pixel 14a, but here, they are separated from the central portion of the X-ray line sensor 14. Since the X-rays are obliquely irradiated to the pixels 14a in the portion, the shadows of the side surfaces BS21 and BS22 are reflected on the two or more pixels 14a of the X-ray line sensor 14.
[0051]
For this reason, in the X-ray raw image 51 of the box BX2 and the contents U in the box BX2, as shown in FIG. 17A, both sides in the direction in which the X-ray line sensor 14 extends (conveyor width direction). Surfaces BS21 and BS22 appear thick, and both side surfaces BS23 and BS24 located forward and rearward in the transport direction appear thin. Then, when the binarization process is performed on the image 51 of FIG. 17A, a processed image 52 from which the boundary line shown in FIG. 17B is extracted is obtained. Here, the side surfaces BS21, BS22, BS23, BS24 of the box BX2 to be masked with respect to the four-sided boundary lines S11 to S14 indicating the outer shape of the box BX2, the side surfaces BS23, BS24 before and after the conveying direction, and the conveyor width direction The thicknesses of the side surfaces BS21 and BS22 at both ends are different. The thicknesses of the side surfaces BS23 and BS24 are the dimension L1, the thicknesses of the side surfaces BS21 and BS22 are the dimension L2, and the dimension L2 is larger than the dimension L1.
[0052]
Even in such a case, in the present apparatus 10, the number of expansions when the boundary line S11 enters the inner side (right side), the number of expansions when the boundary line S12 enters the inner side (left side), and the boundary line S13 are set. Since the number of expansions when entering the inner side (lower side) and the number of expansions when entering the inner side (upper side) of the boundary line S14 can be set separately, the side surfaces BS21, It is possible to set an additional mask area only in the portions of BS22, BS23, and BS24 so that the mask area does not cover the contents U. Here, the boundary lines S11 and S12 enter the inside by the number of expansions corresponding to the dimension L2, and the boundary lines S13 and S14 enter the inside by the number of expansions corresponding to the dimension L1.
[0053]
When the commodity is the box BX2 and the contents U in the box BX2, the inspection determination processing routine 29 of the control computer 20 determines whether the quantity of the contents U in the box BX2 is normal / It is also possible to determine abnormality.
<Characteristics of X-ray inspection equipment>
(1)
In the present apparatus 10, X-rays from the X-ray irradiator 13 pass through the product when the product is present, and directly reach each pixel 14 a of the X-ray line sensor 14 at other times. Based on the processed images 42, 43, 44, 52 obtained by processing the raw images 41, 51 by X-rays, the inspection determination processing routine 29 of the control computer 20 determines that no foreign matter is mixed in the product, or An inspection determination is made as to whether or not the quantity of the contents U in the box BX2 is normal.
[0054]
In the apparatus 10, in the creation of the processed images 42, 43, 44, 52 by the image processing routine 28 of the control computer 20, the boundary lines S11 to S14 between the product and the background are extracted, and the boundary lines S11 to S11 are further extracted. The boundary lines S21 to S24 are generated from S14, and the inspection determination processing routine 29 of the control computer 20 performs the inspection determination on the inspection target area W6 (see FIG. 11) surrounded by the boundary lines S21 to S24. For this reason, even when the position and posture of a product passing between the X-ray irradiator 13 and the X-ray line sensor 14 are deviated, the portion of the product that needs to be inspected is surely the region to be inspected (inspection target Area W6) is entered, and the product defect inspection is appropriately performed.
[0055]
(2)
In the present apparatus 10, boundary lines S11 to S14 between the product and the background are extracted, and an additional left mask area W51, an additional right mask area W52, an additional upper mask area W53, and an additional area are added in the vicinity of the boundary lines S11 to S14. A lower mask area W54 is set. Then, additional mask areas W51 to W54 are added to the background area W1 that is an area outside the boundary lines S11 to S14 to generate a mask area W7 (see FIG. 11) in which the background area W1 is expanded inward. Yes. In other words, an area obtained by subtracting the additional mask areas W51 to W54 from the area inside the boundary lines S11 to S14 is the inspection target area W6 shown in FIG.
[0056]
In this way, the area inside the boundary lines S11 to S14 where the product is present is not set as the inspection target area, but the space between the side BS11 to BS14, the side BS11 to BS14 of the box BX1 and the tube T from there. The inspection target area W6 from which the cap portion T1 of the tube T and the folded back portion T2 at the lower end are removed is generated, and the inspection determination processing routine 29 of the control computer 20 performs the inspection determination on the inspection target area W6.
[0057]
As a result, when it is desired to inspect the contents contained in the tube 1 in the box BX1 shown in FIG. 9A, the aggregate of the contents U in the box BX2 shown in FIG. Even if it is desired to be an inspection target, the inspection target area can be appropriately specified.
(3)
In the present apparatus 10, for a product in which the tube T moves in a box, a characteristic shape of the tube T is stored, and a portion corresponding to the shape is an image after binarization processing. 42, the number of expansions is adjusted. Specifically, the external shape in the vicinity of the cap of the tube T is stored in the HDD 25, and a shape C (see FIG. 15) that matches the external shape is detected from the image 42, and the shape in the region inside the boundary lines S11 to S14. The number of expansions is adjusted according to the position of C.
[0058]
Thereby, even when the tube T moves in the box, the number of expansions is corrected accordingly, and an appropriate mask area is generated in a portion other than the inside of the tube T.
(4)
In this apparatus 10, in the processed images 43 and 51 from which the boundary lines S11 to S14 are extracted, different mask regions (mask areas W51 to W54) can be set in the vicinity of the boundary lines S11 to S14. For this reason, when inspecting the inside of a box whose periphery differs in thickness depending on the part, only the part of the box can be appropriately set as a mask area.
[0059]
For example, when quantity inspection is performed on the contents U in the box BX2 shown in FIG. 17A, the side surfaces BS21, BS22, BS23, BS24 of the box BX2 are to be masked, but the X-ray irradiator 13 Since the line line sensor 14 is irradiated with X-rays in a fan shape, the side surfaces BS21 and BS22 appear thick and the side surfaces BS23 and BS24 appear thin, and the background area outside the boundary lines S11 to S14 is simply expanded. Then, the side surfaces BS21, BS22, BS23, BS24 are not properly masked. However, since the number of expansions corresponding to each of the boundary lines S11 to S14 can be set in advance here, the vicinity of the side surfaces BS21 and BS22 can be masked thickly and the vicinity of the side surfaces BS23 and BS24 can be masked thinly. It is.
[0060]
【The invention's effect】
In the present invention, in the creation of the processed image by the image processing unit, the boundary between the specimen and the background is extracted, and the inspection unit performs the inspection for the inner region of the boundary. For this reason, even when the position or posture of the specimen passing between the X-ray source and the X-ray light receiving unit is deviated, the part that requires examination of the specimen surely enters the region to be examined, and the specimen Inspected properly.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an X-ray inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a simplified configuration diagram inside a shield box of an X-ray inspection apparatus.
FIG. 3 is a schematic diagram showing the principle of X-ray inspection.
FIG. 4 is a diagram showing a configuration before and after an X-ray inspection apparatus.
FIG. 5 is a block diagram of a control computer.
FIG. 6 is a diagram showing a trace reference level in the trace detection method.
FIG. 7 is a diagram showing a reference level in a binarization detection method.
FIG. 8 is a diagram showing creation of a mask area.
FIG. 9A is a view showing an X-ray raw image of a product in which a tube containing toothpaste is contained in a box.
(B) The figure which shows the processed image of the X-ray after a binarization process.
FIG. 10A is a view showing a processed image that has been subjected to image processing for distinguishing between a background area outside the product and other areas;
(B) The figure which shows the method when adding a mask area.
FIG. 11 is a view showing a mask area and an inspection target area in which a background area is expanded separately in the vertical and horizontal directions;
FIG. 12A is a diagram in which a boundary line between a mask area and an inspection target area is superimposed on an X-ray image of a boxed product in which foreign matter is mixed in a tube.
(B) The figure which shows the final processed image of X-ray used as the basis of a test | inspection determination process.
FIG. 13A is a diagram showing a method for setting a mask area when a product is placed on the conveyor in an oblique state.
(B) The figure which shows the mask area and test | inspection area in case goods are mounted in the diagonal state on the conveyor.
FIG. 14 is a diagram showing that the tube movement in the box cannot be handled simply by using the number of expansions of the top, bottom, left, and right.
FIG. 15 is a diagram showing detection of an outer shape near a cap of a tube in an X-ray processed image in order to adjust four times of expansion.
FIG. 16 is a diagram showing how X-rays hit a side of a product box on a conveyor.
FIG. 17A is a diagram showing that front and rear side surfaces and left and right side surfaces of a box appear on an X-ray image with different thicknesses.
(B) The figure which shows the processed image of the X-ray in which the boundary line appeared by binarization.
[Explanation of symbols]
10 X-ray inspection equipment
13 X-ray irradiator (X-ray source)
14 X-ray line sensor (X-ray detector)
14a Pixel (element)
20 Control computer
28 Image processing routine (image processing unit)
28a Mask area setting processing subroutine (mask area setting section)
29 Inspection determination processing routine (inspection unit)
41,51 X-ray raw image
42, 43, 44, 52 X-ray processed images
BS11-BS14 Box side
BS21, BS22 Both sides of the box transport direction (second part)
BS23, BS24 Box sides in the conveyor width direction (first part)
BX1, BX2 box
C Shape (predetermined shape) that matches the external shape near the cap of the tube
S11, S12, S13, S14 boundary line
T tube
U contents
W6 Area to be inspected (region inside the border of the processed image excluding the mask area)

Claims (6)

An X-ray source that emits X-rays;
An X-ray light receiving unit for receiving X-rays from the X-ray source;
An image processing unit for processing a raw image by X-rays received by the X-ray light receiving unit to create a processed image;
Based on the processed image, an inspection unit for inspecting a specimen passing between the X-ray source and the X-ray light receiving unit;
With
The image processing unit creates the processed image through a step of extracting a boundary between the specimen and the background outside the specimen from the raw image,
The inspection unit performs the inspection for an inner region of the boundary of the processed image.
X-ray inspection equipment. The specimen is composed of a package and contents in the package, and receives the X-ray during transportation.
The light receiving unit is an X-ray line sensor in which a plurality of elements that receive X-rays radiated from the X-ray source extend in a second direction substantially orthogonal to a first direction that is a specimen transport direction. ,
A first mask region for the vicinity of the first portion of the boundary located at both ends of the processed image in the first direction, and a second portion of the boundary positioned at both ends of the processed image in the second direction. A mask area setting unit capable of separately setting the second mask area for the neighborhood;
The inspection unit performs the inspection on an inner region of the boundary of the processed image from which the first and second mask regions are removed;
The X-ray inspection apparatus according to claim 1. A mask region setting unit for setting a mask region for the vicinity of the boundary of the processed image;
The inspection unit performs the inspection for an inner region of the boundary of the processed image from which the mask region is removed.
The X-ray inspection apparatus according to claim 1. The mask region setting unit stores a predetermined shape of at least a part of the specimen, finds a portion corresponding to the predetermined shape from the processed image, and sets the mask region based on the portion.
The X-ray inspection apparatus according to claim 3. The mask area setting unit separately sets a mask area for each of the vicinity of the plurality of portions on the boundary of the processed image,
The inspection unit performs the inspection for an inner region of the boundary of the processed image from which the plurality of mask regions are removed.
The X-ray inspection apparatus according to claim 3. The specimen is a box having a plurality of sides and contents contained in the box,
The X-ray inspection apparatus according to claim 5, wherein a plurality of portions of the boundary of the processed image respectively correspond to sides of the box.

Images