JP2005351794A - X-ray inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray inspection device allowing proper inspection all the time, by eliminating an influence of an X-ray shielded by a guide part to set a mask area. <P>SOLUTION: In this X-ray inspection device, a conveyer guide 12d for guiding an article conveyed by a conveyer 12 not to come off out of a conveying passage is arranged in an irradiation area of the X-ray emitted from an x-ray irradiation device 13 to be crossed on an X-ray line sensor 14. A mask area setting part 31c sets an image area formed by an image forming part 31a, as the mask area, on the basis of an X-ray detection amount in a picture element 14a of the X-ray line sensor 14 with a reduced X-ray detection amount because of shielding of the X-ray by the conveyer guide 12d. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an X-ray inspection apparatus that inspects foreign matter contamination by irradiating an article to be conveyed with X-rays.

  Conventionally, in the production line of products such as food, in order to prevent the defective product from being shipped when foreign matter is mixed into the product or the product is cracked or broken, the product has failed using an X-ray inspection device. Inspection is being conducted. In this X-ray inspection apparatus, X-rays are irradiated to an object to be inspected continuously, the transmission state of the X-ray is detected by an X-ray light receiving unit, and foreign matter is mixed in the object to be inspected. It is determined whether there is no cracks in the inspection object or whether the quantity of the unit contents in the inspection object is insufficient. Moreover, the X-ray inspection apparatus may perform an inspection for counting the number of unit contents in the inspection object.

  In some X-ray inspection apparatuses, for example, an image is formed by detecting transmitted light of radiation applied to an object to be inspected, and the presence or absence of foreign matter is determined based on this image information. In this X-ray inspection apparatus, using a characteristic that a foreign object such as metal, stone, or glass is displayed darker than an object to be inspected such as food, pixels in a predetermined density range included in the image are extracted, When the area of the extracted pixel cluster is a predetermined size or more, it is determined as a foreign object.

In such an X-ray inspection apparatus, in general, when an article to be inspected is transported in a shield box that is inspected by irradiating X-rays, the article is not removed from the transport path. An annexed guide is provided.
For example, in Patent Document 1, a guide unit is provided along the conveyance path, and an article to be inspected is reliably guided to the inspection area. However, in the X-ray inspection apparatus disclosed in Patent Document 1, when the guide unit is arranged so as to intersect with a part of the light receiving unit that detects X-rays in plan view, the X-ray is detected by the guide unit. As a result, the article to be inspected may not be properly inspected.

On the other hand, Patent Document 2 discloses an X-ray inspection apparatus that transports an article to be inspected prior to the inspection, sets a reference parameter (mask area, etc.), and determines the inspection using the reference parameter. Is disclosed. According to the X-ray inspection apparatus disclosed in Patent Document 2, it is possible to perform appropriate inspection efficiently and efficiently by quickly and simply setting the reference parameters.
JP 2002-328101 A (published on November 15, 2002) JP 2002-148212 A (published on May 22, 2002)

However, the conventional X-ray inspection apparatus has the following problems.
That is, in the X-ray inspection apparatus disclosed in Patent Document 2, the test product is conveyed by the conveyor and the reference parameter is initially set. However, the reference parameter is set while the test product including the foreign matter is conveyed. This is to be created, and the influence of the guide portion is not particularly taken into consideration. For this reason, in the X-ray inspection apparatus disclosed in Patent Document 2, when a part of the light receiving unit is blocked by the guide unit, the X-ray inspection apparatus is appropriate, for example, by determining this part as a foreign object. There is a risk that the inspection cannot be performed.

  An object of the present invention is to provide an X-ray inspection apparatus capable of setting a mask region while eliminating the influence of X-rays shielded by a guide portion and always performing an appropriate inspection.

  An X-ray inspection apparatus according to a first invention includes an irradiation unit, a light receiving unit, a transport unit, a guide unit, an image forming unit, and a mask region setting unit. The irradiating unit irradiates an article to be inspected with X-rays. The light receiving unit detects X-rays emitted from the irradiation unit. The transport unit is disposed between the irradiation unit and the light receiving unit, and transports articles. The guide unit is arranged at a position that shields part of the X-rays detected by the light receiving unit along the conveyance path formed by the conveyance unit. The image forming unit forms an image based on the X-ray dose detected by the light receiving unit. The mask area setting unit is formed in the image forming unit based on the X-ray dose detected at the position of the light receiving unit that is irradiated with X-rays from the irradiation unit and shielded by the guide unit before starting the inspection. An image area is set as a mask area.

Here, in an X-ray inspection apparatus that performs foreign object inspection or the like, X-rays are irradiated before starting inspection of an article, and, for example, X-rays are blocked by a guide unit arranged so as to cross over the light receiving unit. The position of the light receiving unit is detected. Then, a region of an image formed based on the X-ray dose detected at the position of the light receiving unit is set as a mask region to be excluded from the inspection target.
In a conventional X-ray inspection apparatus, for example, cutting is performed in the middle so that detection of X-rays in a light receiving unit such as a line sensor is hindered by a guide unit disposed on the upper part and improper inspection is not performed. The guide portion is arranged so as to avoid the position of the light receiving portion by detouring. However, in this case, there is a possibility that the article is caught and stays at the cut portion or the detour portion.

Therefore, in the X-ray inspection apparatus of the present invention, an area of an image formed based on the X-ray dose detected at the position of the light receiving section where X-rays are blocked by the guide section is set as a mask area, and this mask area is Exclude from inspection.
Thereby, even when the guide unit provided in the conveyance unit is arranged at a position that blocks the X-rays irradiated from the irradiation unit to the light receiving unit, an area that is not subject to inspection is automatically set. Thus, an appropriate inspection can be performed without being adversely affected by the X-rays being shielded by the guide portion. As a result, for example, it is possible to use a linear guide section that crosses the light receiving section, and it is not necessary to cut or bypass the guide section in the middle, thereby simplifying the structure of the guide section and reducing costs. Can be planned. Furthermore, it is possible to prevent the occurrence of problems such as the article being transported being caught by the cut portion or the detour portion and staying.

An X-ray inspection apparatus according to a second aspect of the present invention is the X-ray inspection apparatus according to the first aspect of the present invention, wherein the mask area setting unit is combined with calibration for adjusting the detection sensitivity of the light receiving unit before starting the inspection. To set the mask area.
Here, the mask region is set together with calibration for correcting the detection sensitivity of the light receiving unit, which is generally performed in a conventional X-ray inspection apparatus.

As a result, it is possible to efficiently correct and optimize the light receiving portion before the start of inspection, thereby improving the efficiency of the entire inspection.
An X-ray inspection apparatus according to a third invention is the X-ray inspection apparatus according to the first or second invention, wherein the mask region setting unit detects X-rays in the light receiving unit after irradiating the X-rays from the irradiation unit. An average value of the quantities is calculated, and an area of an image formed by the image forming unit is set as a mask area based on the X-ray dose detected in an area that is 10 to 50% or less of the average value.

Here, the average value of the X-ray dose detected in the light-receiving unit is calculated, and the image formed based on the X-ray dose detected at the position of the light-receiving unit where the detected amount of X-rays is 10 to 50% or less. Set the area as a mask area.
This makes it possible to easily set the position of the light receiving portion where the X-ray is blocked by the guide portion and the detection amount is reduced as a mask region corresponding to the guide portion.

An X-ray inspection apparatus according to a fourth invention is the X-ray inspection apparatus according to any one of the first to third inventions, wherein the light receiving section is a line sensor having a plurality of pixels.
Here, a line sensor having a plurality of pixels can be used as the light receiving unit.
Thus, for example, by arranging the line sensor from the lower part of one guide part to the lower part of the other guide part in a direction orthogonal to the transport direction, the entire article flowing on the transport path can be inspected.

An X-ray inspection apparatus according to a fifth aspect of the present invention is the X-ray inspection apparatus according to the fourth aspect of the present invention, wherein the mask region setting unit is detected in pixels included in the line sensor where the X-rays are shielded by the guide unit. A region of an image formed by the image forming unit is set as a mask region based on the X-ray dose.
Here, an image region corresponding to a pixel that clearly has a smaller X-ray dose than the other pixels among the plurality of pixels constituting the line sensor is set as a mask region.

Thereby, the mask area can be set for the area of the image corresponding to each pixel.
An X-ray inspection apparatus according to a sixth aspect of the present invention is the X-ray inspection apparatus according to the fifth aspect of the present invention, wherein the mask region setting unit includes a pixel in which X-rays are blocked by the guide unit and several pixels on both sides thereof. A region of an image formed in the image forming unit is set as a mask region based on the X-ray dose detected in the pixel group including the mask.

Here, in addition to the pixels with a small amount of detection because the X-rays are blocked by the guide unit, an image area corresponding to a pixel group including up to several pixels on both sides is set as a mask area.
Thereby, for example, even when the guide part vibrates with the conveyance of the article, it is possible to exclude the influence of the shielding by the guide part arranged at the position where the X-ray is shielded and perform an appropriate inspection. Become.

An X-ray inspection apparatus according to a seventh aspect of the present invention is the X-ray inspection apparatus according to any one of the first to sixth aspects of the present invention, in which the mask area setting unit conveys the article by the conveyance unit. The mask area is set based on the detection result of the X-rays irradiated in the state.
Here, the mask area is set based on the detection result of the X-rays irradiated while conveying the article to be inspected.

In this way, by setting the mask area under the same conditions as after the actual inspection has started, it is possible to perform a more appropriate inspection in consideration of the influence of vibration and the like accompanying the conveyance of the article.
An X-ray inspection apparatus according to an eighth aspect of the present invention is the X-ray inspection apparatus according to any one of the first to seventh aspects of the present invention, which stores the pattern of the light receiving unit that is shielded by the guide unit. The storage unit is further provided.

Here, a storage unit is further provided for storing a pattern (number of guides, width, position, etc.) corresponding to the feature of the guide unit to be detected in the light receiving unit.
Accordingly, whether or not the mask area is properly set can be confirmed based on whether or not the position of the light receiving section corresponding to the image set as the mask area matches the feature of the guide section. Thereby, it is possible to avoid improper inspection by applying an erroneously set mask region.

An X-ray inspection apparatus according to a ninth aspect is the X-ray inspection apparatus according to any one of the first to eighth aspects, wherein the guide portion is attached in a detachable state.
Here, since the guide part is detachable, only the guide part can be removed and cleaned.
For this reason, even when a food or the like is inspected as an object to be inspected, the guide portion can be washed and always kept clean. Furthermore, even when the guide portion is frequently attached and detached, the mask area can be automatically set before the inspection is started, so that stable and appropriate inspection can be performed.

  According to the X-ray inspection apparatus of the present invention, it is possible to perform an appropriate inspection without being adversely affected by the X-rays being shielded by the guide unit, simplify the configuration of the guide unit, and reduce costs. In addition, it is possible to prevent the occurrence of problems such as the article being transported being caught by the cut part or the detour part.

An X-ray inspection apparatus according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 9B.
[Configuration of X-ray inspection system as a whole]
As shown in FIG. 1, the X-ray inspection apparatus 10 of the present embodiment is one of apparatuses that perform quality inspection in a production line for products such as food. The X-ray inspection apparatus 10 irradiates X-rays to products that are continuously conveyed, and inspects whether or not foreign substances are mixed in the products based on the X-ray dose that has passed through the products.

  As shown in FIG. 2, the product G that is the inspection object of the X-ray inspection apparatus 10 is carried 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 transmitted 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 as it is when the product G is determined to be a non-defective product in the X-ray inspection apparatus 10. On the other hand, when the product G is determined to be a defective product in the X-ray inspection apparatus 10, the arm 70a having the downstream end as a rotation shaft rotates so as to block the conveyance path. As a result, the product G determined to be defective can be collected by the defective product collection box 90 arranged at a position off the conveyance path.

  As shown in FIG. 1, the X-ray inspection apparatus 10 mainly includes a shield box 11, a conveyor (conveying unit) 12, a shielding noren 16, and a monitor (display device) 26 with a touch panel function. . In addition, as shown in FIG. 3, a conveyor 12, an X-ray irradiator (irradiation unit) 13, an X-ray line sensor (light receiving unit) 14, and a control computer (control unit) 20 shown in FIG. I have.

[Shield box]
The shield box 11 has an opening 11a for carrying in and out the product on both the entrance side and the exit side of the product G. 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.
Further, as shown in FIG. 1, the opening 11 a is closed by a shield noren 16 in order to prevent leakage of X-rays to the outside of the shield box 11. This shielding nolen 16 has a rubber nolene portion containing lead, and is pushed away by the product when the product is carried in and out.

Further, in addition to the monitor 26, 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 commodities in the shield box 11, and is driven by a conveyor motor 12f included in the control block shown in FIG. The conveyance speed of the conveyor 12 is finely controlled by the inverter control of the conveyor motor 12f by the control computer 20 so as to be the set speed input by the operator.

  Moreover, the conveyor 12 has the conveyor belt 12a, the conveyor frame 12b, the opening part 12c, and the conveyor guide (guide part) 12d, as shown in FIG. The conveyor 12 is attached to the shield box 11 in a removable state. As a result, even when food or the like is handled as an inspection target, the conveyor can be removed and frequently washed to keep the inside of the shield box 11 clean.

The conveyor belt 12a is an endless belt, and is supported by the conveyor frame 12b from the inside of the belt. And the object mounted on the belt is conveyed in a predetermined direction by receiving the driving force of the conveyor motor 12f and rotating.
The conveyor frame 12b supports the conveyor belt 12a from the inside of the endless belt, and has an opening 12c that is long in the direction orthogonal to the conveying direction at a position facing the inner surface of the conveyor belt 12a. ing.

  The opening 12c is formed on a line connecting the X-ray irradiator 13 and the X-ray line sensor 14 in the conveyor frame 12b. In other words, the opening 12c is formed in the X-ray irradiation region from the X-ray irradiator 13 in the conveyor frame 12b. Thereby, the X-ray which permeate | transmitted the goods G permeate | transmits the conveyor belt 12a, and is detected in the X-ray line sensor 14 without being shielded by the conveyor frame 12b.

  The conveyor guide 12d is provided on both sides of the conveyor belt 12a that forms the conveyance path for the product G, and guides the article so that the article moving on the conveyor 12 does not deviate from the conveyance path. In other words, as shown in FIG. 4, the conveyor guide 12 d crosses over the X-ray line sensor 14 disposed below the conveyor 12 and intersects the X-ray line sensor 14 in plan view. These are arranged in the irradiation region of the X-rays irradiated from the X-ray irradiator 13. For this reason, in some pixels 14a included in the X-ray line sensor 14 whose X-rays are blocked by the conveyor guide 12d, if there is no conveyor guide 12d, the detection amount should be equal to the irradiation amount. Only a very small amount of X-rays can be detected. Furthermore, the conveyor guide 12d is attached to the shield box 11 together with the conveyor 12 in a detachable state. For this reason, even when food or the like is handled as an inspection target, the inside of the shield box 11 can always be kept clean by removing and cleaning the entire conveyor 12.

[X-ray irradiator]
As shown in FIG. 3, the X-ray irradiator 13 is disposed above the conveyor 12 and is disposed below the conveyor 12 through an opening 12c formed in the conveyor frame 12b. (Light receiving part, line sensor) X-rays are irradiated in a fan shape toward the light 14 (see the hatched part in FIG. 3).

Note that the X-rays emitted from the X-ray irradiator 13 are emitted over a region including the pixels 14a at both ends of the X-ray line sensor 14 as shown in FIGS. 3 and 5A.
[X-ray line sensor]
The X-ray line sensor 14 is disposed below the conveyor 12 and detects X-rays transmitted through the product G and the conveyor belt 12a. As shown in FIG. 5A and the like, the X-ray line sensor 14 includes a plurality of pixels 14 a that are horizontally arranged in a straight line in a direction orthogonal to the conveying direction by the conveyor 12.

  5A and 5B show the X-ray irradiation state in the X-ray inspection apparatus 10 and the X-ray dose detected in each pixel 14a constituting the X-ray line sensor 14 at that time. Each graph is shown. The dotted lines in the graphs shown at the bottom of each figure correspond to the positions of the pixels 14a where the X-rays are blocked by the conveyor guide 12d in the X-ray irradiation state shown at the top. The same applies to FIGS. 9A and 9B described later.

And in the X-ray line sensor 14, as shown to Fig.5 (a), since a part of X-ray irradiated in fan shape by the conveyor guide 12d is interrupted | blocked, as shown in FIG.5 (b), There are two pixel groups (two to three consecutive pixels) in which the detected amount of X-rays is smaller than that of the other pixels 14a.
In the X-ray inspection apparatus 10 of this embodiment, a pixel group in the X-ray line sensor 14 in which the detection amount of X-rays is reduced is detected as a guide candidate position, and the X-ray inspection apparatus 10 is formed based on the X-ray dose detected in this pixel group. An image area is set as a mask area. Thereby, the detection results in the plurality of pixels 14a whose X-rays are shielded by the conveyor guide 12d can be excluded from the inspection results as mask regions. A specific inspection method in the X-ray inspection apparatus 10 will be described in detail later.

〔monitor〕
The monitor 26 is a full dot display liquid crystal display. Further, the monitor 26 has a touch panel function, and displays a screen that prompts input of parameters relating to initial setting and defect determination.
The monitor 26 displays an X-ray image formed by an image forming unit 31a (see FIG. 7) of the control computer 20 described later. As a result, the presence / absence, location, size, etc. of foreign matter contained in the product G can be visually recognized by the user. Furthermore, the monitor 26 displays the detection result of the conveyor guide 12d described later.

[Control computer]
As shown in FIG. 6, the control computer 20 includes a CPU 21 and a ROM 22, a RAM 23, and a CF (Compact Flash (registered trademark)) 25 as a main storage unit controlled by the CPU 21. The CF 25 stores a threshold file 25a for storing a threshold value of the density, an inspection result log file 25b for storing inspection images and inspection results, and the like.

The control computer 20 also includes a display control circuit that controls data display on the monitor 26, a key input circuit that captures key input data from the touch panel of the monitor 26, and an I / O for controlling data printing in a printer (not shown). USB 24 as an external input terminal is provided.
Storage units such as the CPU 21, ROM 22, RAM 23, and CF 25 are connected to each other via bus lines such as an address bus and a data bus.

The control computer 20 is connected to a conveyor motor 12f, a rotary encoder 12g, an X-ray irradiator 13, an X-ray line sensor 14, a photoelectric sensor 15, and the like.
The rotary encoder 12g is attached to the conveyor motor 12f, detects the conveying speed of the conveyor 12, and transmits it to the control computer 20.
The X-ray irradiator 13 is controlled by the control computer 20 to control X-ray irradiation timing, X-ray irradiation amount, X-ray irradiation prohibition, and the like.

  The X-ray line sensor 14 detects the pixel 14a where X-rays are shielded by the conveyor guide 12d when the mask area is set before the start of inspection, and transmits this X-ray shielding pattern to the control computer 20. . Furthermore, the X-ray line sensor 14 transmits a signal value based on the X-ray dose detected in each pixel 14 a to the control computer 20 after the examination is started.

The photoelectric sensor 15 is a synchronous sensor for detecting the timing at which the product G, which is the object to be inspected, 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. Yes.
The control computer 20 has the above-described configuration, and the CPU 21 shown in FIG. 6 reads various programs stored in the storage unit such as the CF 25, and the image forming unit 31a and the inspection determination as shown in FIG. The processing unit 31b and the mask area setting unit 31c are formed as functional blocks.

The image forming unit 31 a is a functional block formed by the CPU 21 reading an image forming program stored in the storage unit (CF 25 or the like), and forms an X-ray image based on the detection result of the X-ray line sensor 14. .
The inspection determination processing unit 31b is a functional block formed by the CPU 21 reading an inspection determination program stored in the storage unit, and determines the presence or absence of foreign matter based on the X-ray image formed by the image forming unit 31a. To do.

  The mask area setting unit 31c is a functional block formed by the CPU 21 reading a mask area setting program stored in the storage unit, and the X-ray line is shielded by the conveyor guide 12d when the mask area is set. A region of an image formed by the image forming unit 31a is set as a mask region based on the X-ray dose detected by the pixel 14a of the sensor 14.

<Determination of product defects by control computer>
[Create X-ray image]
The control computer 20 receives a signal from the photoelectric sensor 15, and the product G passes through the fan-shaped X-ray irradiation region (see the hatched portion shown in FIGS. 3 and 5A) and the X-ray line sensor 14. X-ray fluoroscopic image signals (see FIG. 8) are acquired at fine time intervals, and the image forming unit 31a described above creates an X-ray image of the product G based on these X-ray fluoroscopic image signals. That is, data at each time is obtained from each pixel 14a of the X-ray line sensor 14 with a fine time interval, and a two-dimensional image is created from these data.

[Foreign matter contamination inspection]
In the control computer 20, the inspection determination processing unit 31b performs image processing on the X-ray image created by the image forming unit 31a, and determines whether the product is good or bad (whether foreign matter is not mixed) by a plurality of determination methods. to decide. Examples of the determination method include a trace detection method and a binarization detection method. As a result of the determination by these determination methods, if there is even one that is determined to be defective (the foreign object image shown in FIG. 8), the product G is determined to be defective.

In the trace detection method and the binarization detection method, foreign matter contamination is determined for an image region other than the mask region. The mask area is set for the conveyor guide 12d, the container portion of the product G, and the like. The setting of the mask area will be described in detail later.
The trace detection method is a method in which a reference level (threshold value) is set along the approximate thickness of an object to be detected, and it is determined that foreign matter is mixed in the product G when the image becomes darker than that. is there. In this method, a product defect can be detected by detecting a relatively small foreign object.

[Setting of mask area by X-ray inspection equipment]
In the X-ray inspection apparatus 10 of the present embodiment, a mask area for setting an image area that is not to be inspected is set together with calibration that is performed before the start of inspection for contamination. This calibration starts the inspection of data for making the X-ray detection sensitivities uniform in each pixel by correcting the detection sensitivities caused by the individual pixels 14a of the X-ray line sensor 14 due to temperature and the like. What to get before. Then, the mask area set here is excluded from the area of the image created in the image forming unit 31a to be a non-inspection area, and then the inspection determination processing unit 31b performs the inspection for the contamination as described above. .

  That is, in the X-ray inspection apparatus 10 of the present embodiment, as shown in FIG. 5A, the two conveyor guides 12 d are irradiated from the X-ray irradiator 13 so as to cross the X-ray line sensor 14. It is disposed within the X-ray irradiation range. For this reason, as shown in FIG. 5B, there are two clusters of pixels 14a in which the detected amount of X-rays in the X-ray line sensor 14 is significantly smaller than other pixels.

In the X-ray inspection apparatus 10 according to the present embodiment, the pixel 14a in which the amount of X-ray detection is significantly reduced is detected as a guide candidate position, and an image formed based on the X-ray dose detected at the pixel 14a. Set the area as a mask area.
In the setting of the mask region, as shown in FIG. 5B, after calculating the average value (Ave) of the X-ray dose detected in each pixel 14a, the average value is 20% (Ave / 5) or less. The pixel 14a is set as a guide candidate position. Then, an image area formed based on the X-ray dose detected in the pixel 14a at the guide candidate position is set as a mask area. In other words, at the time of performing the inspection, the detection result of the pixel 14a detected as the guide candidate position is excluded from the inspection target and the determination is performed.

  Note that the calibration and mask area setting performed before the start of the contamination inspection is performed while the inspection sample is conveyed by the conveyor 12. In this way, by performing calibration and setting the mask area in a state where the actual inspection is performed, the mask area is set more accurately in consideration of the vibration of the conveyor guide 12d and the like during the inspection. be able to.

  Further, the X-ray inspection apparatus 10 according to the present embodiment has a pattern on the X-ray line sensor 14 that is shielded by the conveyor guide 12d (the position and number of pixels 14a that are shielded by the X-ray line sensor 14). The maximum / minimum value of the size of the lump) is stored in a storage unit such as CF25 for each conveyor guide 12d. Such parameters of the conveyor guide 12d are determined based on the detection result of the X-ray line sensor 14 by irradiating X-rays with the conveyor guide 12d correctly attached in advance in the conveyor guide setting mode. As a result, when setting the mask area, if the detected guide candidate position matches the parameter of the conveyor guide 12d stored in the storage unit such as the CF 25, the mask area is determined based on the detection result. On the other hand, if they do not match, an undetected message of the conveyor guide 12d can be displayed on the monitor 26 to notify the user.

  In the setting of the parameters of the conveyor guide 12d, when the number of consecutive pixels 14a in which the X-ray detection amount has decreased is equal to or larger than a predetermined number, this may be detected as being shielded by the conveyor guide 12d. . For example, only in the case of a continuous pixel group of 5 pixels or more, this is set as a parameter corresponding to one conveyor guide 12d. Thereby, in the X-ray line sensor 14, when the fine foreign material adhering to the surface of the conveyor 12 is detected, this can be made not to detect as a parameter of the conveyor guide 12d.

  Furthermore, in the X-ray inspection apparatus 10 according to the present embodiment, when it is desired to perform a proper inspection more reliably in consideration of the vibration of the conveyor guide 12d and the like, the setting reference of the mask area is switched by changing the setting of the user. An image region detected in a pixel group including several pixels (for example, two pixels) on both sides of the pixel 14a as a guide candidate position can be set as a mask region.

  Specifically, as shown in FIG. 9A, a pixel 14a serving as a guide candidate position is detected from the detection result in the X-ray line sensor 14, and thereafter, as shown in FIG. 9B, the guide candidate position is detected. The mask area is expanded to the image area detected in the pixel group including two pixels on both sides of the pixel 14a. Thus, by enlarging the mask area, accurate inspection can be performed even when the position of the conveyor guide 12d is slightly shifted due to vibration or the like after the start of inspection.

[Features of X-ray inspection equipment]
(1)
In the X-ray inspection apparatus 10 of the present embodiment, as shown in FIGS. 3 to 5, an X-ray irradiation region irradiated from the X-ray irradiator 13 so as to cross the X-ray line sensor 14 is used by a conveyor 12. A conveyor guide 12d that guides the product to be conveyed so as not to be removed from the conveyance path is disposed. Then, the mask area setting unit 31c forms the image forming unit 31a on the basis of the X-ray detection amount in the pixel 14a of the X-ray line sensor 14 whose X-ray detection amount is reduced by shielding the X-rays by the conveyor guide 12d. An image area is set as a mask area.

  Thereby, it is possible to perform inspection by excluding the image region set as the mask region from the X-ray image formed in the image forming unit 31a (see FIG. 7). For this reason, a part of the conveyor guide 12d is arranged in the X-ray irradiation area, and even if there are pixels in the X-ray line sensor 14 that are shielded by the conveyor guide 12d, the appropriateness is not affected. An inspection can be performed.

  Further, since proper inspection can be performed even if the conveyor guide 12d is placed on the X-ray line sensor 14, the conveyor guide 12d is cut or detoured at a position intersecting the X-ray line sensor 14 in a plan view. For example, a conveyor guide 12d having a simple linear configuration can be used. As a result, there are the effects of reducing the manufacturing cost of the conveyor guide 12d and avoiding the stagnation of articles in the cut or detoured portion of the conveyor guide.

(2)
In the X-ray inspection apparatus 10 of the present embodiment, the mask region setting by the mask region setting unit 31c acquires data for correcting the difference in detection sensitivity in each pixel 14a of the X-ray line sensor 14 before the start of inspection. This is performed together with the calibration performed for the purpose.

Thereby, since the mask area is set in conjunction with calibration generally performed before the start of the inspection, the mask area is efficiently set and the X-ray line sensor 14 can be optimized.
(3)
In the X-ray inspection apparatus 10 of the present embodiment, as shown in FIG. 5B, when the mask area setting unit 31c sets the mask area, the detection results of all the pixels 14a of the X-ray line sensor 14 are displayed. An average value is calculated, and a pixel 14a that is 20% or less of the average value is detected as a guide candidate position. Then, an image area corresponding to the pixel 14a detected as the guide candidate position is set as a mask area.

As a result, the pixel 14a whose X-rays are shielded by the conveyor guide 12d is easily detected as a guide candidate position based on a reference value of 20% or less of the average value, and according to the detection result in the pixel corresponding to the guide candidate position. The image area formed in this manner can be set as a mask area.
As described above, the reference of the pixel 14a detected as the guide candidate position is not limited to 20% or less of the average value of the X-ray dose detected in all the pixels, and is, for example, 10 to 50% or less. The reference value may be changed within the range.

(4)
In the X-ray inspection apparatus 10 of the present embodiment, as shown in FIGS. 3 and 5A, X-rays are detected by an X-ray line sensor 14 having a plurality of pixels 14a, and calibration and mask area setting are performed. An X-ray image is formed.
Thereby, the inspection of the articles conveyed by the conveyor 12 can be performed by arranging the X-ray line sensor 14 constituted by the plurality of pixels 14a in a direction orthogonal to the conveyance direction. In addition, since the guide candidate position detected when setting the mask region can be detected in units of pixels, the inspection can be performed by excluding the inspection result in the pixel detected as the guide candidate position.

(5)
In the X-ray inspection apparatus 10 of the present embodiment, an image region formed based on the X-ray dose detected in the pixel group including the pixels on both sides of the pixel 14a that is the guide candidate position is set as a mask region.
As a result, even if the conveyor guide 12d moves due to vibration or the like during the inspection, it can be excluded from the object of foreign matter determination, so that it is based on the X-ray dose detected at the pixel 14a set as the guide candidate position. As compared with the case where the formed image area is set as a mask area as it is, an appropriate inspection can be performed more reliably.

(6)
In the X-ray inspection apparatus 10 of the present embodiment, the mask area is set while the test article is conveyed by the conveyor 12.
Accordingly, since the mask area can be set in almost the same state as that during the inspection, even if the conveyor guide 12d vibrates somewhat due to vibrations caused by conveyance, the range of the vibrating conveyor guide 12d is reduced. The mask area can be set to include. Therefore, more appropriate inspection can be performed without being affected by the X-ray shielding by the conveyor guide 12d.

(7)
In the X-ray inspection apparatus 10 of the present embodiment, the pattern on the X-ray line sensor 14 that is shielded by the conveyor guide 12d is stored in a storage unit such as the CF25. Here, the pattern on the X-ray line sensor 14 that shields X-rays by the conveyor guide 12d refers to the position and number of pixels 14a that shield X-rays by the conveyor guide 12d, and the size of the clusters of pixels 14a. Information including maximum / minimum values.

  Thus, when setting the mask area, it is possible to confirm whether the mask area is properly set by comparing the pattern corresponding to the currently installed conveyor guide 12d with the stored pattern. it can. Specifically, if the detected guide candidate position matches the pattern stored in the storage unit such as the CF 25 and matches, the mask area is set based on the detection result, while the pattern does not match In this case, an undetected message of the conveyor guide 12d is displayed on the monitor 26 to notify the user.

As a result, it is possible to avoid improper inspection by excluding the mask region set in error from the inspection target.
(8)
In the X-ray inspection apparatus 10 of this embodiment, the conveyor guide 12d is attached in the shield box 11 in a detachable state.

Thereby, even if it is an X-ray inspection apparatus which uses foodstuff etc. as a test subject, the inside of the shield box 11 can always be kept clean by frequently removing and cleaning the conveyor guide 12d.
[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

(A)
In the above embodiment, when setting the mask area, the image area formed based on the X-ray dose detected in the pixel 14a detected as the guide candidate position is set as the mask area as it is, and the pixel detected as the guide candidate position. A case where an image region formed based on an X-ray dose detected in a pixel group including several pixels on both sides of 14a is set as a mask region will be described as an example in which one of the setting methods is selected according to user settings. did. However, the present invention is not limited to this.

For example, it may be an X-ray inspection apparatus that sets a mask region by performing only one of the methods.
In the latter method, an example is described in which the pixel serving as a reference for mask area setting is extended to a pixel group including two pixels on both sides of the pixel detected as the guide candidate position. However, the present invention is not limited to this.

For example, instead of extending to both sides of the pixel at the guide candidate position, it may be expanded to only one side of the pixel at the guide candidate position. Furthermore, the number of pixels to be expanded is not limited to two pixels, and the number of pixels to be expanded can be changed so that an appropriate inspection can be performed in consideration of the vibration state of the conveyor guide 12d and the like.
(B)
In the said embodiment, the conveyor guide 12d demonstrated and demonstrated the example arrange | positioned at the right and left in the conveyance direction of the conveyor belt 12a. However, the present invention is not limited to this.

For example, the conveyor guides arranged only on one side of the conveyor belt 12a and the conveyor guides that stabilize the posture by pressing the object from the upper part when inspecting an object that easily rolls, The same applies.
(C)
In the above-described embodiment, an example in which a linear guide having a simple configuration is used as the conveyor guide 12d has been described. However, the present invention is not limited to this.

For example, even for a guide configured to include a curved shape and a cut portion, an area that shields X-rays detected by the line sensor is set as a mask area and excluded from the inspection target, as in the above embodiment. By doing so, an appropriate inspection can be carried out.
However, even when the guide having a simple configuration such as a straight line is arranged on the line sensor as in the above embodiment, an appropriate inspection can be performed by setting the mask area described above. It is more preferable to have a simple configuration such as a straight line in terms of reducing the manufacturing cost of the guide.

(D)
In the above-described embodiment, an example has been described in which an article to be inspected is irradiated with X-rays to inspect foreign matters and the like. However, the present invention is not limited to this.
For example, it is possible to perform inspection using other radiation such as β-rays, γ-rays, and electromagnetic waves.

  The X-ray inspection apparatus of the present invention has an effect that an appropriate inspection can be performed without being adversely affected by the shielding of the X-rays by the guide portion, and thus a member that shields the X-rays on the line sensor. It can be widely applied to X-ray inspection apparatuses provided with

1 is an external perspective view of an X-ray inspection apparatus according to an embodiment of the present invention. The figure which shows the structure before and behind an X-ray inspection apparatus. The simple block diagram inside the shield box of a X-ray inspection apparatus. The top view which shows the conveyor inside the shield box of a X-ray inspection apparatus. (A) is a figure which shows the X-ray irradiation state at the time of conveyor mounting, (b) is a graph which shows the X-ray detection amount in the line sensor at that time. The block block diagram of a control computer. The functional block which the control computer of FIG. 6 has. The schematic diagram which shows the principle of a X-ray inspection. (A) is a figure which shows the X-ray detection amount of a line sensor, and the guide candidate position which can be read from a graph, (b) is the figure which set the mask area | region based on the graph of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 X-ray inspection apparatus 11 Shield box 11a Opening 12 Conveyor 12a Conveyor belt 12b Conveyor frame 12c Opening part 12d Conveyor guide (guide part)
12e slit 12f conveyor motor (drive mechanism)
12g Rotary encoder 13 X-ray irradiator (irradiation part)
14 X-ray line sensor (light receiving part, line sensor)
14a pixel 15 photoelectric sensor 16 shielding nolen 20 control computer 21 CPU
22 ROM (storage unit)
23 RAM (storage unit)
24 USB (external connection terminal)
25 CF (compact flash, storage unit)
26 Monitor 31a Image forming unit 31b Inspection determination processing unit 31c Mask area setting unit G Product

Claims (9)

An irradiation unit for irradiating an article to be inspected with X-rays;
A light receiving unit for detecting X-rays emitted from the irradiation unit;
A transport unit disposed between the irradiation unit and the light receiving unit, for transporting the article;
A guide unit disposed at a position that shields a part of the X-rays detected by the light receiving unit along a transport path formed by the transport unit;
An image forming unit that forms an image based on the X-ray dose detected in the light receiving unit;
Formed in the image forming unit based on the X-ray dose detected at the position of the light receiving unit that is irradiated with X-rays from the irradiation unit and shielded by the guide unit before starting the inspection. A mask area setting unit for setting an image area as a mask area;
X-ray inspection apparatus. The mask region setting unit sets the mask region together with calibration for adjusting detection sensitivity of the light receiving unit before starting the inspection;
The X-ray inspection apparatus according to claim 1. The mask area setting unit calculates an average value of detected amounts of X-rays in the light receiving unit after irradiating X-rays from the irradiation unit, and detects an X-ray dose detected in a region that is 10 to 50% or less of the average value A region of the image formed by the image forming unit based on the mask region,
The X-ray inspection apparatus according to claim 1 or 2. The light receiving unit is a line sensor having a plurality of pixels.
The X-ray inspection apparatus according to any one of claims 1 to 3. The mask area setting unit uses, as the mask area, an area of the image formed by the image forming unit based on an X-ray amount detected in a pixel included in the line sensor where X-rays are shielded by the guide part. Set,
The X-ray inspection apparatus according to claim 4. The mask region setting unit is a region of the image formed in the image forming unit based on an X-ray dose detected in a pixel group including a pixel whose X-rays are blocked by the guide unit and several pixels on both sides thereof. Is set as the mask area,
The X-ray inspection apparatus according to claim 5. The mask area setting unit sets the mask area based on a detection result of X-rays irradiated while the article is being conveyed by the conveyance unit.
The X-ray inspection apparatus according to any one of claims 1 to 6. A storage unit that stores a pattern of the light receiving unit that is shielded from X-rays by the guide unit;
The X-ray inspection apparatus according to any one of claims 1 to 7. The guide part is attached in a detachable state,
The X-ray inspection apparatus according to any one of claims 1 to 8.

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