JP2005024453A - X-ray inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray inspection device capable of stably inspecting missing items by reducing the influence on the conveyance direction due to displacement. <P>SOLUTION: A mask region setting means 15a sets a mask region for detecting missing items compatible with the contents of an object to be inspected. A reference position calculating means 19 compares the X-ray transmission image of the contents obtained, when the object to be inspected is exposed to X-rays, with a reference position detection limit value preset according to the arrangement of the contents, and discriminates the position of the X-ray transmission image of the contents exceeding the reference position detecting limit value first, as nearly the tip position of the contents positioned at the top of a housing body for calculating as a reference position. A missing item discriminating means 20a overlaps the X-ray transmission image of the contents to the set mask region for missing item detection, for discriminating the presence or absence of the missing item of the contents with the reference position calculated by the reference position calculation means set as a reference. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an X-ray inspection apparatus that detects foreign matter in an inspection object from the amount of X-ray transmission when X-rays are exposed, and in particular, X-ray that can accurately detect a missing item in the inspection object. It relates to an inspection device.
[0002]
[Prior art]
The X-ray foreign object detection apparatus irradiates X-rays to inspection objects of various varieties (for example, raw meat, fish, processed foods, medicines, etc.) that are sequentially transported on the transport line, and It is a device that detects whether or not foreign matter such as metal, glass, stone, and bone is mixed in the object to be inspected from the amount of transmission.
Prior art document information relating to the invention of this application includes the following.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-228761
[0004]
By the way, when the contents are accommodated in a container such as a tray or a box as an object to be inspected, this type of X-ray foreign object detection device accommodates the object in the pre-processing stage for determining the presence or absence of foreign objects in the object to be inspected. The presence / absence of contents in the body is detected to determine a missing item (defective product).
[0005]
In this shortage determination process, a shortage detection mask area is set in advance on the coordinate axis position assuming the storage position of the content in the container, and the image is developed based on the X-ray transmission data at the time of X-ray exposure. And the missing item detection mask area are overlapped, and if the contents exist in the missing item detection mask area, the inspection object is judged to be normal, and the contents exist in the missing item detection mask area. If not, the inspected item is judged as a missing item (defective product).
[0006]
However, in the above-described conventional shortage determination process, if the contents do not completely overlap within the shortage detection mask area, it is determined that the object to be inspected is a shortage. In some cases, the contents were misjudged as missing parts even if the contents were present in the container.
[0007]
Therefore, in order to cope with the above problem, the present applicant has already proposed the X foreign object detection device disclosed in Patent Document 1. In the X-ray foreign matter detection apparatus disclosed in Patent Document 1, a missing part detection mask region is set with reference to the tip position of a container in which contents are stored as an inspection object, and the set missing part detection is performed. The presence / absence of a missing item is determined based on the ratio of the area of the contents in the mask area.
[0008]
[Problems to be solved by the invention]
According to the X-ray foreign object detection device disclosed in Patent Document 1 above, if the package or tray as the container has a certain degree of rigidity, the tip position of the container does not change. Can be detected with high accuracy. However, if there is variation in the tip of the container relative to the transport direction, the missing part detection mask area is entirely displaced depending on the position of the tip of the container to be detected, leading to an erroneous determination of the missing part. There was a fear.
[0009]
When a specific example is shown and described, for example, in the case of an inspected object in which a plurality of contents are packed in a film-like package as a container, the amount of movement of the contents in the package in the transport direction is extremely high. Few. However, as shown in FIGS. 7A and 7B, the container S used for accommodating this type of inspected object varies depending on how the seal portion Sa is bent.
[0010]
When the inspection object W having a variation in the state of the seal part Sa is a shortage inspection target, the tip position of the seal part Sa of the package S is used in the X-ray foreign object detection device disclosed in Patent Document 1. A missing part detection mask area is set with reference to P. For this reason, in the state of FIG. 7A, a missing item detection mask region is set with reference to the tip position P1 of the seal portion Sa of the package S. On the other hand, in the state of FIG. 7B, a missing part detection mask region is set with reference to the tip position P2 of the bent seal portion Sa. Therefore, when the X-ray foreign object detection device disclosed in Patent Document 1 is employed, the tip position shifts due to variations in the seal portion Sa of the package S as shown in FIGS. There is a risk that the missing part detection mask area will be entirely displaced with respect to the transport direction by the amount t1, and the proportion of the area of the content Wa in the missing part detection mask area will change, resulting in erroneous missing part inspection. was there.
[0011]
In addition, for example, in the case of retort food that uses shochu and dumplings as the contents Wa, as shown in FIG. 8, in a state where a plurality of shochu and dumplings are arranged on the tray T as the contents to be inspected. It is packaged in a film-shaped package S. In such a case, the tray T may move in the package S with respect to the transport direction even if the tip position of the seal portion Sa of the package S does not change.
[0012]
For this reason, when the missing item inspection is performed using the X-ray foreign matter detecting device disclosed in Patent Document 1, the missing item detection mask area is set with reference to the tip position of the package S. The missing item detection mask area is displaced as a whole with respect to the transport direction by the amount of movement, and as described above, the proportion of the area of the content Wa in the missing item detection mask area changes, resulting in an incorrect missing item. There was a risk of inspection.
[0013]
By the way, when the to-be-inspected object W by which the several content Wa was arrange | positioned on the tray T in the package S as mentioned above is made into a missing item inspection object, the front-end | tip of the tray T in the package S shown in FIG. It is also conceivable to set a missing part detection mask region based on the position P3. However, in many cases, this type of tray T is often formed thin, and it is difficult to distinguish the tray T from X-ray transmission data at the time of X-ray exposure, and detection by X-rays is difficult. Even when the leading edge position P3 of the tray T can be detected and the missing part detection mask area is set with reference to the leading edge position P3 of the tray T, as shown in FIGS. When the content Wa moves on the tray T in S with respect to the transport direction, the inspection detection mask area is entirely displaced by the amount of movement t2 of the content Wa. There was a risk that the proportion of the area of the content Wa in the region would change and an incorrect shortage inspection was performed.
[0014]
Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide an X-ray inspection apparatus capable of performing a stable shortage inspection while reducing the influence of a positional deviation in the transport direction. To do.
[0015]
[Means for Solving the Problems]
Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
The X-ray inspection apparatus according to claim 1 exposes an X-ray to the inspection object W accommodated in a container, and inspects the inspection object based on an X-ray transmission amount associated with the X-ray exposure. In the X-ray inspection apparatus 1 that performs
Based on an X-ray transmission image of the contents Wa of the inspection object obtained by setting a missing part detection mask region M that matches the contents of the inspection object and exposing the inspection object to X-rays. With the approximate tip position of the content located at the head of the container detected in this manner as a reference position RF, the X-ray transmission image of the content and the missing item detection mask region are overlapped, and the missing portion of the content is detected. A signal processing means 14 for determining the presence or absence of a product is provided.
[0016]
The X-ray inspection apparatus according to claim 2 irradiates the inspection object W accommodated in the container with X-rays, and inspects the inspection object based on an X-ray transmission amount associated with the X-ray exposure. In the X-ray inspection apparatus 1 that performs
A mask area setting means 15a for setting a missing part detection mask area M that matches the contents of the inspection object;
X-ray transmission image of the content Wa of the inspection object obtained at the time of X-ray exposure to the inspection object, and a reference position detection limit value set in advance according to the arrangement of the content of the inspection object And the position of the X-ray transmission image of the content that first exceeds the reference position detection limit value is determined as the approximate tip position of the content located at the head of the container and is calculated as a reference position RF. Position calculating means 19;
A discriminating unit for discriminating whether or not the content item is missing by superimposing the X-ray transmission image of the content and the missing item detection mask area on the basis of the reference position calculated by the reference position calculating unit; It is provided with.
[0017]
The X-ray inspection apparatus according to claim 3 is the X-ray inspection apparatus according to claim 2,
The discriminating means 20 determines whether the content is missing based on a comparison between the ratio of the area of the X-ray transmission image of the content Wa contained in the missing part detection mask region M and a preset reference value. It is characterized by determining the presence or absence of goods.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an X-ray inspection apparatus according to the invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is an external view of an X-ray inspection apparatus according to the present invention, FIG. 2 is a block diagram showing an electrical configuration of the X-ray inspection apparatus according to the present invention, and FIGS. FIG. 4 is a diagram showing an example of a missing part inspection target to be inspected by a line inspection apparatus and the level of an X-ray transmission image thereof; FIG. 4 is a diagram showing an example of a missing part detection mask region; FIG. 6A is a diagram showing a state in which an object to be inspected is normally accommodated in the container, FIG. 6B is a diagram showing a state in which the object to be inspected is missing, FIG. FIG. 6C is a diagram for explaining the discrimination process based on the area ratio. FIG. 3 (c) schematically shows a light and shade level in which only the contents are emphasized.
[0020]
The X-ray inspection apparatus 1 of the present example is provided in a part of the transport line and inspects for missing items (presence / absence of missing items) of the inspected items that are sequentially conveyed at predetermined intervals. A foreign matter contamination inspection (presence or absence of foreign matter contamination in the inspection object) is performed.
[0021]
In particular, the X-ray inspection apparatus 1 of this example is suitable for the case where the shortage inspection is stably performed when the contents are accommodated in the container as the inspection object.
[0022]
The inspection object to be inspected for shortage is one in which the contents are contained in the container, and the contents do not move more than half in the container in a normal state. Specifically, the content Wa is packaged by the package S as the inspection object W as shown in FIG. 3, and the content Wa is arranged on the tray T as the inspection object W as shown in FIG. And the like packaged by the package S.
[0023]
In this example, only the package S or the package S containing the tray T is referred to as a container. Further, in this example, an example in which eight contents Wa are accommodated in the package S as the inspection object W is described.
[0024]
In the X-ray inspection apparatus 1 shown in FIG. 1, a conveyance unit 2 and a foreign matter detection unit 3 are provided in the apparatus main body 4, and a display 5 is provided in the upper front portion of the apparatus main body 4.
[0025]
The transport unit 2 sequentially transports the same type of inspection object W in which the contents Wa are stored in a container (the package S or a combination of the package S and the tray T) at predetermined intervals. This conveyance part 2 can be comprised with the belt conveyor arrange | positioned horizontally with respect to the apparatus main body 4, for example. The conveyance unit 2 directs the inspection object W carried in from the carry-in port 7 at a predetermined conveyance speed set in advance by driving of the drive motor 6 shown in FIG. 1 toward the carry-out port 8 (carrying direction X in FIG. 1). To transport.
[0026]
The foreign matter detection unit 3 detects the presence or absence of a missing part or the presence of foreign matter in the middle of the transport path of the workpiece W to be transported, and an X-ray generator provided at a predetermined height above the transport unit 2 9 and an X-ray detector 10 provided in the transport unit 2 so as to face the X-ray generator 9.
[0027]
The X-ray generator 9 has a configuration in which a cylindrical X-ray tube 12 provided in a metal box 11 is immersed in insulating oil (not shown), and an electron beam from the cathode of the X-ray tube 12 is an anode target. X-rays are generated by irradiation. The X-ray tube 12 is provided in a direction (Y direction in FIG. 1) whose longitudinal direction is orthogonal to the conveyance direction X of the inspection object W. The X-rays generated by the X-ray tube 12 are exposed to the lower X-ray detector 10 in the form of a substantially triangular screen by a slit (not shown) along the longitudinal direction.
[0028]
The X-ray detector 10 detects X-rays transmitted through the inspection object W when the X-rays are exposed to the inspection object W accommodated in the container S, and the detected X-rays are detected. An electrical signal corresponding to the transmission amount of the line is output. The X-ray detector 10 is provided along the Y direction orthogonal to the transport direction X of the inspection object W transported on the transport unit 2. The X-ray detector 10 uses an array line sensor including a plurality of photodiodes arranged in a line and a scintillator provided on the photodiode.
[0029]
As shown in FIG. 2, position detection means 13 for detecting the passage of the inspection object W is provided on the carry-in entrance 7 side of the transport unit 2. This position detection means 13 is comprised by the photo sensor which consists of a pair of light projector / receiver provided in the entrance side of the belt conveyor as the conveyance part 2, for example. With this configuration, an ON signal is input from the position detection unit 13 to the signal processing unit 14 as a timing signal while the inspection object W passes in front of the photosensor.
[0030]
In the X-ray detector 10 having such a configuration, X-rays are exposed from the X-ray generator 9 to the inspection object W transported on the transport unit 2. Then, the X-ray transmitted through the inspection object W with the X-ray exposure to the inspection object W is received by the scintillator and converted into light. The light converted by the scintillator is received by a photodiode disposed under the scintillator. Each photodiode converts the received light into an electrical signal and outputs it. The X-ray detector 10 outputs an electric signal having a level corresponding to the intensity of the received X-ray to the signal processing means 14.
[0031]
In FIG. 2, the signal processing unit 14 includes a CPU, a memory, and the like, and an on signal when the position detection unit 13 detects the inspection object W is used as a timing signal, and the position detection unit 13 outputs an on signal. The period during which it is determined is the length of the inspection object W (packaging body S), and various signal processings are performed by taking in an electrical signal from the X-ray detector 10.
[0032]
As shown in FIG. 2, the signal processing unit 14 includes a setting input unit 15, a storage unit (data memory) 16, and an image processing unit 17.
[0033]
The setting input means 15 includes a plurality of settings operated by the user for giving various settings regarding the missing item inspection and foreign matter mixing inspection of the contents Wa contained in the package S as the inspection object W, various settings regarding display, and various instructions. Consists of keys and switches.
[0034]
As shown in FIG. 2, the setting input means 15 has a mask area setting means 15a. This mask area setting means 15a preliminarily inspects each object to be inspected according to the arrangement of the contents Wa in the container when performing a lack inspection of the contents Wa stored in the package S as the object to be inspected. Of the plurality of types of missing part detection mask areas M stored, a missing part detection mask area M that matches the contents Wa of the inspection object W to be inspected is set. As shown in FIG. 4, in the missing part detection mask area M, the coordinate axis positions x and y and the mask ranges xL and yL are set for each mask area with the approximate tip position of the first content Wa as a reference. Is selected and set. As shown in FIGS. 4 and 5, the missing part detection mask area M is based on the reference position RF, and the coordinate axis positions x and y of each mask area are substantially the centers of the corresponding contents Wa of the object W to be inspected. The mask ranges xL and yL are set according to the size of the contents Wa.
[0035]
More specifically, the coordinate axis positions x and y and the mask ranges xL and yL of the setting items can be set by actually transporting the inspection object W by the transport unit 2 at the initial setting before performing the inspection. For example, a plurality of objects to be inspected stored without missing items in the container are prepared as samples, and the above setting items are changed while being transported by the transport unit 2 to confirm whether or not “OK” is determined. At this time, the coordinate axis positions x and y are moved to various places in the container, and the mask ranges xL and yL are changed to check whether or not “OK” is determined for all samples. In addition to the above setting items, the value when the area ratio B is varied and becomes “OK” in all samples is set as the best setting. Note that when performing the above setting, it is confirmed whether or not all samples in a state where no contents are stored in the container are determined to be “NG”.
[0036]
In addition to the above settings, the setting input means 15 sets the conveyance speed of the conveyance unit 2, the setting of a reference position detection limit value used as a reference when calculating a reference position RF described later, and the presence / absence of a missing item described later. The setting of the area ratio B used for the discrimination and the foreign matter detection limit value serving as a reference for discriminating the presence or absence of foreign matter in the inspection object W are set.
[0037]
The area ratio B and each detection limit value depend on the ratio of the area occupied by the contents Wa in the package S, the type of the package S, the type of the inspection object W, the type of foreign matter to be detected, and the like. Can be set as appropriate.
[0038]
The storage means 16 stores X-ray transmission data for each inspection object W. This X-ray transmission data is obtained by taking in data obtained by A / D converting the electrical signal from the X-ray detector 10 by an A / D converter (not shown) at the detection timing of the position detecting means 13. To explain further, for example, 640 pieces of X-ray transmission data per line (Y direction in FIG. 1) of the X-ray detector 10 are stored in the storage means 16 every time one inspection object W is inspected. A predetermined number of lines (480 lines) corresponding to at least the length in the transport direction of the inspection object W to be transported (corresponding to a detection period from the front end to the rear end) is stored.
[0039]
The image processing unit 17 performs various types of image processing based on the X-ray transmission data of one inspection object W stored in the storage unit 16, and includes a content image extraction unit 18, a mask reference position calculation unit 19, and a discrimination. Means 20 are provided. Further, the image processing means 17 displays and outputs image data indicating the X-ray transmission amount output from the X-ray detector 10 on the display 5. At this time, the display density of the foreign matter portion in the inspection object W is displayed so as to be different from other portions, or is displayed in a color different from that other than the foreign matter portion. Thereby, the state of the outer shape of the inspection object W in which the contents Wa are accommodated in the package S as viewed in a plane, and the transmission of X-rays in the inspection object W are displayed on the display screen of the display 5. It is possible to confirm the position of the foreign object, and the position where the foreign substance is mixed can be grasped. Further, the image processing means 17 displays and outputs on the display 5 the results of OK / NG judgment results and the inspection results such as the total number of inspections, the number of non-defective products, and the total number of NG.
[0040]
The content image extracting means 18 is an extracted image A of only the content Wa of the inspection object W excluding the package S as shown in FIG. 5 from the X-ray transmission image based on the X-ray transmission data stored in the storage means 16. Is extracted. When extracting the extracted image A of only the contents Wa, a detection limit value is set by the setting input means 15 in the vicinity of a substantially intermediate level between the X-ray transmission amounts of the container and the contents Wa in advance. In general, since the content Wa has a lower X-ray transmission amount than the container, the content image extraction means 18 is an area lower than the detection limit value in the X-ray transmission image based on the X-ray transmission data in the storage means 16. Is extracted as the content Wa, and the extracted image A of only the content Wa is extracted. The extracted image A containing only the content Wa is processed as an image having a predetermined gray level.
[0041]
The mask reference position calculation means 19 determines the density level of the extracted image A of the contents Wa of the inspection object W obtained when the inspection object W is exposed to X-rays and the arrangement of the contents Wa of the inspection object W. Accordingly, the reference position detection limit value set in advance is compared, and the position of the density level of the content Wa that first exceeds the reference position detection limit value is contained (packaging body S or packaging body S containing the tray T). Is determined as the approximate tip position of the content Wa located at the head of the content, and the approximate tip position is calculated as the reference position RF.
[0042]
More specifically, in this mask reference position calculation means 19, when the sulfur-extracted image A having a predetermined shading level of only the contents Wa of the inspection object W extracted by the contents image extraction means 18 is inputted, The gray level of the pixel for each line (direction orthogonal to the conveyance direction) of the extracted image A is compared with the reference position detection limit value set in advance by the setting input unit 15. Then, the position where the gray level of the pixel for each line exceeds the reference position detection limit value is determined as the head position of the first content Wa, and the position is calculated as the reference position RF. The reference position detection limit value is set in advance from the setting input unit 15 in accordance with the content Wa of the inspection object W, and is set to a value at which the content Wa of the inspection object W can be detected. For example, when the content Wa of the inspection object W is spherical, the intermediate value between the content Wa and the belt surface of the transport unit 2 is set.
[0043]
The determination unit 20 includes a shortage determination unit 20a, a foreign matter determination unit 20b, and a pass / fail determination unit 20c. The missing item discriminating means 20a reads the missing item detection mask area M set in advance by the mask area setting means 15a, and the reference position calculated by the mask reference position calculating means 19 based on the detection of the leading position of the contents Wa. Using the RF as a reference, the read out missing part detection mask area M and the extracted image A of the contents Wa are overlapped to determine whether there is a missing part. The process of determining whether or not there is a shortage is performed by a logical product operation of each pixel described below. This AND operation is performed by scanning in units of pixels, and if the extracted image A of the content Wa is positioned within the shortage detection mask area M in an overlapped state, one pixel is detected. Count one by one. The shortage detection mask area M to be set has the number of pixels n, and the count value CNT is increased to the number of pixels of the extracted image A of the contents Wa included in the shortage detection mask area M. become.
[0044]
FIG. 6A is a view showing a state in which the contents Wa are normally accommodated in the package S. FIG. FIG. 6A shows a state in which the missing part detection mask region M and the extracted image A of the contents Wa are superimposed. In the state of FIG. 6A, since the missing part detection mask area M includes all of the extracted images A of the contents Wa, the count value CNT matches the number of pixels n in the missing part detection mask area M ( (Strictly, it is almost the same)
[0045]
The shortage determination means 20a compares the count value CNT with the number of pixels n × area ratio B of the shortage detection mask area M. If the count value CNT is higher, “OK” is obtained, and the count value CNT is greater. Is low, it is determined as “NG (out of stock)”. In the example of FIG. 6A, since the count value CNT substantially matches the number n of pixels in the missing item detection mask area M, it is determined that “OK”, that is, the content Wa exists in the package S. To do. The discrimination result at this time is output as a discrimination signal (OK signal or NG signal) to the pass / fail discrimination means 20c.
[0046]
FIG. 6B is a diagram showing a missing state of the contents Wa. As shown in FIG. 6B, when the content Wa is not present in the package S (out of stock), the shortage detection mask area M and the extracted image A of the content Wa are overlaid. Since the extracted image A of the content Wa is not included in the missing item detection mask area M, the count value CNT is 0 (strictly, a value close to 0 as far as possible). In this case, the shortage determination means 20a compares the count value CNT with the number of pixels n × area ratio B of the shortage detection mask area M, and the count value CNT is lower. ) ”. The discrimination result at this time is output as a discrimination signal (NG signal) to the pass / fail discrimination means 20c.
[0047]
FIG. 6C is a diagram illustrating a detection state of the content Wa by the area ratio. At the time of X-ray detection, the inspected object W may move slightly in the package S, or the tray T on which the content Wa is placed may move in the package S. Therefore, in this example, the presence / absence of the content Wa is determined based on the ratio of the area of the extracted image A of the content Wa occupying the shortage detection mask region M.
[0048]
In the case of FIG. 6C, in a state where the missing part detection mask region M and the extracted image A of the content Wa are overlapped, a part of the extracted image A of the content Wa (substantially half in the illustrated example). 50%) overlaps the missing item detection mask area M and is not included in the entire missing item detection mask area M. In this case, the count value CNT is 2 / n. Here, if 40% is set as the area ratio B by the setting input means 15, the shortage determination means 20 a has the count value CNT and the number of pixels n of the shortage detection mask area M × the area ratio B (40 %) And the count value CNT is higher, the determination result is “OK”, that is, it is determined that the content Wa exists in the package S.
[0049]
The foreign matter discriminating means 20b judges a portion of the content area of the object W to be inspected as a foreign object in the content area where the contrast level is different from the others. More specifically, the foreign matter determination means 20b compares the density level of the X-ray transmission data of the inspection object W stored in the storage means 16 with the foreign matter detection limit value set in advance by the setting input means 15, and X When the line transmission data exceeds the foreign object detection limit value, it is determined that the foreign object is mixed in the inspection object W. The discrimination result at this time is output as a discrimination signal (OK signal or NG signal) to the pass / fail discrimination means 20c. The foreign object detection limit value can be set from the setting input unit 15 as appropriate for each inspection object W.
[0050]
The pass / fail determination means 20c externally outputs a selection signal indicating whether the inspection object W is normal or defective based on the determination signal from the shortage determination means 20a and the determination signal from the foreign matter determination means 20b.
[0051]
That is, in this pass / fail judgment means 20c, when a discrimination signal (OK signal) indicating normality is input from both the missing part discrimination means 20a and the foreign matter discrimination means 20b, it is determined that there is no missing part and no foreign matter in the inspection object W. A discrimination signal indicating normality is output to the outside. On the other hand, when a determination signal (NG signal) indicating a shortage is input from the shortage determination means 20a or a determination signal (NG signal) indicating the entry of foreign matter is input from the foreign matter determination means 20b, It is determined that there is a shortage or foreign matter mixed in W, and a selection signal indicating a defect is output to the outside.
[0052]
On the display screen of the display 5, an X-ray transmission image obtained by planarly viewing the inspection object W based on the determination result of the determination means 20, “OK” or “NG” pass / fail judgment result, total inspection number, non-defective product number, Inspection results such as the total number of NG are displayed based on a predetermined key operation from the setting input means 15.
[0053]
When the missing item inspection of the inspection object W accommodated in the package S is performed using the X-ray inspection apparatus 1 having the above configuration, the following processing is executed in the signal processing unit 14. First, an optimum shortage detection mask region M is input in advance from the maximum region setting means 15a in accordance with the type of the inspection object W to be inspected.
[0054]
When X-rays are exposed to the inspection object W transported on the transport unit 2, X-ray transmission data associated with the X-ray exposure is stored in the storage unit 16. Then, the image processing unit 17 creates an entire grayscale image (entire image including the inspection object W and the belt surface of the transport unit 2) from the X-ray transmission data stored in the storage unit 16.
[0055]
Next, the content extraction means 18 extracts the extracted image A of only the content Wa of the inspection object W excluding the package S from the entire gray image of the created X-ray transmission image.
[0056]
Next, the mask reference position calculation means 19 calculates the pixel gray level for each line (Y direction orthogonal to the conveyance direction X in FIG. 1) of the extracted image A of only the contents Wa of the extracted inspection object W. The reference position detection limit value set in advance by the setting input means 15 is compared. Then, the position where the gray level of the pixel for each line exceeds the reference position detection limit value is determined as the approximate tip position of the first content Wa, and this approximate tip position is calculated as the reference position RF.
[0057]
Thereafter, the shortage determination means 20a reads out a preset shortage detection mask area M from the mask area setting means 15a, and is the approximate tip position of the leading content Wa calculated by the mask reference position calculation means 19. With reference to the reference position RF, the missing part detection mask region M and the extracted image A of the contents Wa are superimposed, and the presence / absence of a missing part is determined by the above-described determination process.
[0058]
By the way, in the X-ray inspection apparatus 1 of the present example, in addition to the above-described shortage inspection of the inspection object W, foreign matter mixed in the inspection object W from the X-ray transmission amount when the inspection object W is exposed to X-rays. An inspection for the presence or absence is also performed.
[0059]
When inspecting the presence or absence of foreign matter in the inspected object W, the X-ray transmission data stored in the storage unit 16 is compared with the foreign matter detection limit value preset by the setting input unit 15. Then, when the X-ray transmission data exceeds the foreign object detection limit value, it is determined that the foreign object is mixed in the inspection object W.
[0060]
As described above, in the X-ray inspection apparatus of the present example, the approximate tip position of the content located at the top of the container of the inspection object being conveyed is detected, and the detected approximate tip position is used as a reference position. The product detection mask area and the extracted image of the contents of the object to be inspected are overlapped to inspect the contents of the object to be inspected. Stable missing item inspection can be performed without being affected by variations in position due to movement.
[0061]
Specifically, as shown in FIG. 3 (c), an extraction image of the missing item detection mask region M and the content Wa is obtained with the approximate tip position of the first content Wa in the package S as the reference position RF. Since the shortage inspection is performed by superimposing, even if the seal part Sa of the package S has a variation due to bending or the like as shown in FIGS. 3A and 3B, it is accurate without being affected by this variation. Stockout inspection can be performed.
[0062]
In addition, when the first content Wa in the package S is missing, the approximate tip position of the next content Wa is set as the reference position RF, and the shortage detection mask area M and the content Wa are extracted. Since the images are overlapped, the missing part detection mask area M is entirely displaced in the transport direction, but there is a mask area that is determined to be a missing part, so that it is prevented from erroneously determining that there is no missing part. it can.
[0063]
Furthermore, even if the contents are actually present in the container, the X-ray may be detected while the contents and the tray on which the contents are placed are moved and shifted in the container. However, in the X-ray inspection apparatus of this example, at the time of the shortage inspection, the ratio of the X-ray transmission image of the contents contained in the shortage detection mask region and the preset reference value (the shortage detection mask region). Based on the comparison with the number of pixels x area ratio), it is possible to prevent the content from being misidentified as “NG (missing item)” and improve the reliability of missing item discrimination. Can be made. Moreover, even if the entire contents are not included in the missing part detection mask area, if the ratio of the area of the contents overlapping in the missing part detection mask area is equal to or larger than a preset area ratio, the contents are It can be detected as existing.
[0064]
Furthermore, since the inspection of foreign matters in the inspection object is simultaneously performed in addition to the shortage inspection of the contents of the inspection object, different inspection items can be performed by one apparatus, and the equipment cost can be reduced.
[0065]
By the way, in the above-described embodiment, the shortage detection mask area M in which one mask area is assigned to one content Wa is used. However, a plurality of masks are used for one content Wa. It is also possible to use a missing part detection mask area to which an area is assigned. In this case, in addition to the shortage inspection of the content Wa, a defect such as a partial chipping of the content Wa can be detected.
[0066]
【The invention's effect】
As described above, according to the X-ray inspection apparatus according to the present invention, the approximate tip position of the content located at the head in the container of the inspection object is detected, and the detected substantially tip position is used as a reference position. Since the missing item detection mask area and the extracted image of the contents of the inspection object are superimposed, the inspection of the contents of the inspection object is performed, so the movement of the contents in the container and the contents are placed. Stable shortage inspection can be performed without being affected by variations in position due to movement of the tray.
[0067]
Further, even when X-rays are detected while the contents and the tray on which the contents are placed are moved and shifted in the container, the X-ray transmission of the contents contained in the shortage detection mask area is performed. Since the presence / absence of a missing item in the contents is determined based on a comparison between the ratio of the area of the image and a preset reference value, it is possible to prevent erroneous determination and improve the reliability of the missing item determination.
[Brief description of the drawings]
FIG. 1 is an external view of an X-ray inspection apparatus according to the present invention.
FIG. 2 is a block diagram showing an electrical configuration of an X-ray inspection apparatus according to the present invention.
FIGS. 3A to 3C are diagrams showing a shortage inspection target to be inspected by the X-ray inspection apparatus according to the present invention and the level of an X-ray transmission image thereof.
FIG. 4 is a diagram illustrating an example of a missing part detection mask region;
FIG. 5 is a diagram illustrating an example of an extracted image of an inspection object accommodated in a container.
FIG. 6A is a diagram showing a state in which an object to be inspected is normally stored in the container.
(B) It is a figure which shows a to-be-inspected item missing item state.
(C) The figure for demonstrating the discrimination | determination process by area ratio It is an external view of the X-ray inspection apparatus which concerns on this invention.
FIG. 7 is a diagram illustrating an example of an object to be inspected accommodated in a container, and is a diagram for explaining a problem when the X-ray foreign object detection device of Patent Document 1 is adopted.
FIG. 8 is a diagram illustrating another example of an object to be inspected accommodated in a container, and is a diagram for explaining a problem when the X-ray foreign object detection device of Patent Document 1 is employed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... X-ray inspection apparatus, 14 ... Signal processing means, 15a ... Mask area setting means, 19 ... Mask reference position calculation means, 20 ... Discrimination means, W ... Inspection object, Wa ... Contents, S ... Container, Sa ... seal part, RF ... reference position.

Claims (3)

X-ray inspection apparatus (1) that inspects the object to be inspected based on the amount of X-ray transmission accompanying the X-ray exposure by exposing the object to be inspected (W) accommodated in the container. In
An X-ray of the contents (Wa) of the inspection object obtained by setting a missing part detection mask region (M) that matches the contents of the inspection object and exposing the inspection object to X-rays. The X-ray transmission image of the contents and the missing item detection mask area are overlapped with the approximate tip position of the contents located at the head of the container detected based on the transmission image as a reference position (RF). An X-ray inspection apparatus comprising signal processing means (14) for determining whether or not the contents are missing. X-ray inspection apparatus (1) that inspects the object to be inspected based on the amount of X-ray transmission accompanying the X-ray exposure by exposing the object to be inspected (W) accommodated in the container. In
Mask area setting means (15a) for setting a missing part detection mask area (M) that matches the contents of the inspection object;
X-ray transmission image of the contents (Wa) of the inspection object obtained at the time of X-ray exposure to the inspection object, and a reference position detection set in advance according to the arrangement of the contents of the inspection object A limit value is compared, and the position of the X-ray transmission image of the content that first exceeds the reference position detection limit value is determined as the approximate tip position of the content positioned at the head of the container, and the reference position (RF) Reference position calculating means (19) for calculating as
Discriminating means (20) for discriminating the presence or absence of a missing part of the content by superimposing the X-ray transmission image of the content and the missing part detection mask region on the basis of the reference position calculated by the reference position calculating means. And an X-ray inspection apparatus. The discriminating means (20) is based on a comparison between the ratio of the area of the X-ray transmission image of the contents (Wa) contained in the missing part detection mask area (M) and a preset reference value. The X-ray inspection apparatus according to claim 2, wherein the presence or absence of the content is determined.

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