JP2004029040A - X-ray foreign matter detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always clearly identify the presence of foreign matters without requiring any adjustment or the like in the amount of illumination of X rays even if the properties of an article to be inspected are not constant in an X-ray foreign matter detecting apparatus for inspecting the presence of the mixture of the foreign matter to the article concerned from a transmission state by illuminating the article to be inspected with X rays. <P>SOLUTION: By specifying the article to be inspected at an input section 12a in an operation section 12, data for setting the amount of illumination such as a correction coefficient according to density can be obtained for the article from a storage section 11c in a control apparatus 11, and the amount of illuminated X rays for illuminating the article to be inspected with light is set based on the data. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an improvement in an X-ray foreign matter detecting device that irradiates an inspected article with X-rays and detects a foreign matter mixed in the article based on a transmission state of the article.

In recent years, there has been an increasing demand for the safety of various products, and in particular, in the case of products such as foods, it is necessary to prevent foreign substances from entering the products as much as possible. In response to such a demand, for example, as disclosed in Patent Literature 1, an X-ray foreign matter detection device for inspecting whether or not foreign matter has been mixed in a produced product has been put into practical use. Have been.

This X-ray foreign matter detector irradiates the packaged article with X-rays, detects the transmission state of the article by a sensor, and processes the detection result by a computer to determine whether foreign matter has entered the article. According to this, it is possible to detect not only metals such as iron, stainless steel and copper mixed in the article, but also non-metallic foreign substances such as stone, glass and plastic, In addition, the inspected article is not limited to an article wrapped with a plastic film or the like, and it is also possible to detect the contamination of foreign objects in articles such as cans and bottles, and articles in a plastic case. .

JP-A-3-246485

By the way, this X-ray foreign matter detection device recognizes the distribution of the X-ray dose transmitted through the inspected article as an image displayed with lightness, and the X-ray transmission amount in the image is small, so that it is unnaturally dark with respect to the surroundings. When there is a part where the foreign matter is present, it is determined that there is a foreign matter in that part. In this case, if the irradiation amount of the X-ray is too large, the amount of X-ray transmitted through the foreign matter increases, and the transmitted X-ray If the amount of irradiation is too small, the amount of transmitted X-rays in a portion where no foreign matter is present becomes insufficient, and the entire image becomes uniformly dark. However, it is difficult to confirm the presence of foreign matter.

To cope with this, it is necessary that the amount of X-ray irradiation can be adjusted so that, when foreign matter is present, a sufficient contrast is generated in a transmitted X-ray image between a portion where the foreign matter exists and a portion where the foreign matter does not exist. Specifically, the amount of X-ray irradiation is adjusted so that the amount of X-ray transmission at a portion where no foreign matter is present, that is, the brightness of the image becomes appropriate.

However, when the inspected article is not constant, the irradiation amount of X-rays at which the image has an appropriate brightness is also different. Therefore, it is necessary to adjust the irradiation amount every time the inspected article is different, which is extremely troublesome. In addition, since the adjustment is insufficient, there is a possibility that the detection accuracy of the foreign matter is deteriorated.

Therefore, the present invention focuses on the fact that the amount of transmitted X-rays depends on the property according to the type of the article, for example, the density. An object of the present invention is to automatically adjust the amount of X-ray irradiation so as to be always an appropriate amount, thereby improving the work efficiency and the foreign matter detection accuracy particularly when the inspected article is not constant.

た め In order to solve the above problems, the present invention is characterized by using the following means.

First, an invention according to claim 1 of the present application (hereinafter, referred to as a first invention) is an X-ray irradiating unit that irradiates an X-ray to an article to be inspected, and a transmission of the X-ray irradiating the inspected article by the irradiating unit. An X-ray foreign matter detection device having foreign matter detection means for detecting foreign matter mixed into the article from a state, wherein a storage means for storing X-ray irradiation amount setting data in advance for each item of the article to be inspected; Item designation means for designating the item and reading the dose setting data for the item from the storage means; and X-ray irradiation for the inspected article using the dose setting data read from the storage means. It is characterized by comprising an irradiation amount setting means for setting an irradiation amount, and a control means for controlling the X-ray irradiation means so as to irradiate X-rays with the irradiation amount set by the setting means.

The invention according to claim 2 (hereinafter, referred to as second invention) is based on the first invention, wherein the storage means stores, as irradiation amount setting data, a density-related amount relating to the density of the article for each item. In addition, the irradiation amount setting means sets the X-ray irradiation amount for irradiating the inspection object using the density-related amount of the item read from the storage means.

According to such a configuration, in any of the first invention and the second invention, when the item of the inspected article is designated by the item designation means, the X-ray irradiation dose for the item stored in advance from the storage means While the setting data is read out, the irradiation amount setting unit sets the irradiation amount using the data, and the control unit controls the X-ray irradiation unit so as to irradiate the inspection object with the X-rays at the irradiation amount. .

In this case, according to the second aspect, a more appropriate X-ray irradiation dose for the article is set by using the density-related quantity related to the density of the article as the dose setting data read from the storage means. Is done. In this case, the correction of the irradiation amount based on the density-related amount is performed, for example, in the case of a high-density article, in the case of a low-density article such that the irradiation amount is larger than a value obtained by multiplying the magnification according to the thickness. It is conceivable that the irradiation is performed so that the irradiation amount is smaller than a value obtained by multiplying the magnification according to the thickness.

Then, as described above, the optimal irradiation dose of X-rays is automatically set for each of the inspected articles, so that the X-ray dose transmitted through the inspected articles is always an appropriate amount without adjustment for each article, When a foreign substance is mixed, it is possible to reliably detect the mixing of the foreign substance, for example, a sufficient contrast is generated in an image formed by the transmitted X-ray.

In the above-described invention, the item to be inspected by the item specifying means may be specified by an operator by inputting an item code or the like, or by specifying an item of the item to be inspected using a television camera or the like, or by using the foreign matter detection device. For example, a case where a signal indicating an item is received from another device connected to the device is included.

Hereinafter, embodiments of the present invention will be described.

As shown in FIG. 1, an X-ray foreign matter detection device 1 according to this embodiment has an X-ray shield box 2 provided with an entrance 2a and an exit 2b for an article to be inspected on both sides, respectively. The carry-in conveyor 3 and the carry-out conveyor 4 are arranged in series. The carry-in conveyor 3 has a start end located at the entrance 2 a, and carries the articles to be inspected into the shield box 2 from the entrance 2 a, and delivers the articles to the carry-out conveyor 4 at the center of the box 2. In addition, the unloading conveyor 4 has a terminating end positioned at the outlet 2b, and conveys the inspected articles received from the infeed conveyor 3 toward the outlet 2b.

In addition, a gap 5 is provided between the end of the carry-in conveyor 3 and the start end of the carry-out conveyor 4 at the center of the shield box 2 so as not to hinder delivery of the articles to be inspected. An X-ray irradiator 6 is arranged above the gap 5, and an X-ray detector 7 is arranged below the gap 5, and these are vertically opposed via the gap 5.

Here, the X-ray irradiator 6 generates X-rays in an amount corresponding to the input power. The X-ray detector 7 has a large number of sensors 7a... 7a arranged in the width direction of the conveyors 3 and 4 along the gap 5 as shown in FIG. An output corresponding to the amount of the incident X-ray is generated.

Further, a thickness measuring device 8 for measuring the thickness of the article to be inspected conveyed by the conveyor 3 is installed near the carry-in conveyor 3 in the shield box 2. As shown in FIG. 3, the thickness measuring device 8 includes a light emitting device 8a disposed on one side of the carry-in conveyor 3 and a light receiving device 8b disposed on the other side, and emits light. A number of light emitters 8a '... 8a' such as light emitting diodes are vertically arranged in a line in the device 8a, and a number of light receivers 8b '. The light-emitting members 8a '... 8a' are arranged in a vertical line so as to face each other. 8a '. The light detected from each of the light emitters 8a'... 8a 'is received without being blocked by the article A to be inspected. The thickness of the inspected article A is detected.

In addition to the above configuration, the foreign object detection device 1 has a control device 11 and an operation device 12, and the operation device 12 is provided with an input unit 12a provided with a number of keys and a display unit 12b. ing. Further, in this embodiment, there is provided a sorting device 21 for separating and inspecting the inspected inspected article into a normal product with no foreign matter mixed therein and an abnormal product with foreign matter mixed therein. Is connected to the terminal end of the unloading conveyor 4 at the outlet 2b of the shield box 2 so that the inspected articles unloaded from the outlet 2b are introduced into the sorting device 21.

Next, a control system of the foreign matter detection device 1 centering on the control device 11 will be described with reference to FIG.

The control device 11 has an X-ray image processing unit 11a for inputting a signal from the X-ray detector 7 and a thickness determining unit 11b for inputting a signal from the thickness detector 8, and has a built-in X-ray detector. The storage unit 11c in which the data for setting the radiation dose is stored, and the input unit 12a and the display unit 12b of the operation device 12 are connected as external devices, and signals are input and output between them. Has become.

Here, the dose setting data stored in the storage unit 11c will be described. As shown in FIG. 5, the storage unit 11c stores a code for each item of each inspected article and a code for the item. The X-ray reference doses X1, X2, ..., Xn, ... and the correction coefficients K1, K2, ..., Kn, ... corresponding to the density of the article are stored in association with each other.

In this case, when the thickness of each type of article is the reference thickness T0, the amount of transmitted X-rays detected by the X-ray detector 7 when the thickness of each type of article is the reference thickness T0 is determined by image processing. This is the irradiation amount when the amount becomes the most suitable amount, and is experimentally obtained in advance using an article of each item having the reference thickness T0. In the case of an article having a high density, for example, if the X-ray irradiation dose is doubled when the thickness is doubled, the density correction coefficient Kn is insufficient. This corresponds to the fact that when the X-ray irradiation amount is doubled, the X-ray irradiation amount may become too large.

The X-ray irradiator 6 and the sorting device 21 control the X-ray irradiator 6 according to the processing result based on the dose setting data stored in the storage unit 11c and the signals input to the processing units 11a and 11b. A signal is output. Next, a specific operation of this control will be described.

First, an item code of an article to be inspected for foreign substances is input through the input unit 12a of the operating device 12, and the article is placed on the carry-in conveyor 3; The X-ray reference irradiation amount Xn and the density correction coefficient Kn are read out, and the carry-in conveyor 3 carries the article into the box 2 from the entrance 2a of the shield box 2.

When the article to be inspected passes through the position where the thickness measuring device 8 is provided during the transportation by the carry-in conveyor 3, the article is moved from each light emitting body 8a '... 8a' of the measuring instrument 8 to each light receiving body 8b '. .., 8b ', the lower one of the detection lights emitted toward 8b' is blocked. At this time, the controller 11 determines the height of the lowermost light receiving body 8b ', which has received the detection light, from the height The thickness T of the inspected article is detected. Then, the amount of X-rays to be irradiated on the article at this time is set based on the thickness T, the reference irradiation amount Xn of X-rays read from the storage unit 11c, and the density correction coefficient Kn.

Specifically, it calculates how many times the thickness T of the inspected article corresponds to the reference thickness T0 when the reference irradiation amount Xn of X-rays is obtained, and calculates the magnification (T / T0) and the density correction. The irradiation amount is calculated by correcting the reference irradiation amount Xn using the coefficient Kn, and when the amount of transmitted X-rays is the reference thickness T0 regardless of the thickness or density of the article to be inspected. This is almost the same as the amount of irradiation at the reference irradiation amount Xn.

Then, the control device 11 applies a voltage corresponding to the irradiation amount to the X-ray irradiator 6 so that the inspection object passes through the gap 5 between the carry-in conveyor 3 and the carry-out conveyor 4. The X-ray irradiator 6 irradiates the inspected article with X-rays at the above-mentioned irradiation dose.

X-rays transmitted through the article to be inspected are detected by an X-ray detector 7 arranged below the gap 5. In this case, the X-ray detector 7 7a arranged in the width direction of the sensor 4, the data from the sensors 7a... 7a is continuously input while the inspected article passes through the gap 5. Two-dimensional data on the entire shape similar to the planar shape of the inspection object is obtained. Then, by processing the two-dimensional data in the X-ray image processing unit 11a, an image having a distribution of lightness and darkness according to the amount of transmitted X-rays can be obtained for the entire planar shape of the inspection object. .

In this case, the amount of transmitted X-rays detected by the X-ray detector 7 is, as described above, the amount obtained when the inspection object is irradiated with the reference irradiation amount Xn when the thickness of the inspection object is the reference thickness T0. However, the amount of transmitted X-rays when irradiating the article having the reference thickness T0 with the reference irradiation amount Xn is most apparent when foreign matter is mixed in the article to be inspected. Since it is an amount that can be identified, even if a foreign substance is mixed in the inspection object having the thickness T, it can be clearly identified by image processing of the transmitted X-ray.

Then, the control device 11 displays the result of the image processing on the display unit 12b of the operation device 12, and determines whether or not a foreign substance has entered based on the presence or absence of an unnatural dark portion in the image. The result is transmitted to the sorting device 21. In addition, when the sorting device 21 receives the result and the foreign object is not mixed in the inspected article received this time from the unloading conveyor 4, the sorting device 21 conveys the foreign object to a predetermined place as a normal product, and If so, the item is transported to a place where abnormal products are discharged.

In this way, the articles supplied to the carry-in conveyor 3 of the foreign object detection device 1 are inspected for the presence of foreign substances, and the articles containing foreign substances are automatically selected and discharged.

Next, another embodiment of the present invention will be described.

As shown in FIG. 6, the X-ray foreign matter detection device 51 according to this embodiment also has an X-ray shield box 52 in which an entrance 52a and an exit 52b of the article to be inspected are provided on both sides, similarly to the above embodiment. In addition, the carry-in conveyor 53 and the carry-out conveyor 54 are arranged in series, and above the gap 55 provided between the end of the carry-in conveyor 53 and the start end of the carry-out conveyor 54 at the center of the shield box 52. , An X-ray irradiator 56 is arranged, and an X-ray detector 57 is arranged below.

Further, a control device 61 for controlling the amount of X-ray irradiation by the X-ray irradiator 56 and the operation of the sorting device 71, and an operation device 62 having an input portion 62a and a display portion 62b are provided. Is the same as in the above embodiment.

In this embodiment, a television camera 58 is installed in the shield box 52 near the carry-in conveyor 53 in place of the thickness measuring device 8 in the embodiment, and the control device 61 , An X-ray image processing unit 61a to which a signal from the X-ray detector 57 is input, and a shape image processing unit 61b for processing the signal from the television camera 58 and recognizing the shape of the inspected article captured. Have been.

According to this embodiment, if the article to be inspected on the carry-in conveyor 53 is imaged by the television camera 58, the signal from the camera 58 is processed by the shape image processing unit 61b of the control device 61 to recognize the shape of the article. The thickness T is obtained as one of the shape data. Then, using the thickness T and the X-ray reference irradiation amount Xn and density correction coefficient Kn for the inspection article read from the storage unit 61c, the X-ray to be irradiated on the article is obtained in the same manner as in the above embodiment. The radiation dose of the line is set.

Thus, also in this embodiment, the amount of transmitted X-rays detected by the X-ray detector 57 becomes the most suitable amount for image processing, and when foreign matter is mixed, it can be reliably detected. become able to.

By the way, by using the television camera 58 for detecting the thickness of the article to be inspected as in this embodiment, the following function can be added to the X-ray foreign matter detection device 51.

That is, in addition to the data of the X-ray reference dose Xn and the density correction coefficient Kn for each item code shown in FIG. 5 and the shape of each item code as shown in FIG. In addition to storing item identification data such as image data and colors, the image data is captured by comparing the shape, color, and the like captured by the television camera 58 and recognized by the shape image processing unit 61b with the stored data. Items can be identified. Therefore, in this case, the input operation of the item code of the article to be inspected using the input unit 62a of the operation device 62 becomes unnecessary, and only the operator places the article to be inspected on the carry-in conveyor 53, and all other operations are performed. The operation will be fully automated.

The details of the article identification method using a television camera have been described in a previous patent application (Japanese Patent Application Laid-Open No. Hei 6-92338) by the present applicant.

Further, by comparing the shape of the article to be inspected imaged by the television camera 58 with the stored shape data of the article, it is also possible to detect an appearance abnormality such as chipping or dent of the article. It is. Further, as shown in FIG. 7, if label attaching data is stored for each item code in the storage unit 61c, the size and position of the label attached to the inspection object are imaged by the television camera 58. By detecting the label from the image and comparing it with the stored label affixing data, it is possible to determine whether or not the predetermined label is correctly affixed at a regular position.

Then, when an abnormality in the appearance of the article, an abnormality in labeling, or the like is detected, the information is sent to the sorting device 71, so that these abnormal products can be discharged to a place different from the normal product. In this case, it is also possible to discharge the abnormal product and the foreign material mixed product separately.

The item to be inspected is identified by key input operation using the input units 12a and 62a of the operation devices 12 and 62, and automatic identification using the television camera 58 and item identification data such as shape and color. An article processing device such as a packaging device or a pricing device is connected to the upstream side of the foreign matter detection devices 1 and 51, and the work by these devices and the foreign matter detection work by the detection devices 1 and 51 are continuously performed. When this is performed, the item code of the article to be inspected may be supplied from these upstream devices to the detection devices 1 and 51.

As described above, according to the present invention, in the X-ray foreign matter detection apparatus, the irradiation amount of the X-ray is automatically adjusted so that the transmitted X-ray dose is always an appropriate amount regardless of the density of the article of the predetermined item. In this way, it is possible to improve the work efficiency and the accuracy of detecting foreign matter, particularly when the article to be inspected is not constant. INDUSTRIAL APPLICATION This invention is widely suitable for the technical field of an X-ray foreign material detection apparatus.

1 is a front view of an X-ray foreign matter detection device according to an embodiment of the present invention. FIG. 2 is a plan view of the X-ray detector as viewed from aa arrow of FIG. 1. FIG. 2 is a side view of the thickness measuring device taken along the line bb in FIG. 1. It is a system diagram showing a control system of the same detecting device. FIG. 3 is an explanatory diagram of data stored in a storage unit of the system. FIG. 7 is a system diagram showing a control system of an X-ray foreign matter detection device according to another embodiment of the present invention. FIG. 3 is an explanatory diagram of data stored in a storage unit of the system.

Explanation of reference numerals

1,51 X-ray foreign matter detector 6,56 X-ray irradiation means (X-ray irradiator)
7,57 X-ray detector 11,61 Foreign matter detection means, irradiation amount setting means, control means (control device)
11c, 61c Storage means (storage unit)
12a, 62a Item setting means (input unit)

Claims (2)

X-ray foreign matter having X-ray irradiating means for irradiating X-rays to the inspected article, and foreign matter detecting means for detecting foreign matter mixed into the article from the transmission state of the X-ray radiated on the inspected article by the irradiating means A detection device, comprising: storage means for preliminarily storing X-ray irradiation dose setting data for each item of an article to be inspected; Item designation means for reading data, irradiation amount setting means for setting an X-ray irradiation amount for irradiating the inspection object using the irradiation amount setting data read from the storage means, and irradiation set by the setting means Control means for controlling said X-ray irradiating means so as to irradiate X-rays in a quantity. The storage unit stores, as the irradiation amount setting data, a density-related amount related to the density of the article for each item, and the irradiation amount setting unit uses the density-related amount of the item read from the storage unit. 2. The X-ray foreign matter detection device according to claim 1, wherein the X-ray irradiation amount for irradiating the inspection object is set.

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