JP2008268035A - Device for inspecting foreign substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely detect foreign matters that have mixed into a product, in a production line where a product that uses a packing material, such as, aluminum evaporation films, and a product does not use it are mixed. <P>SOLUTION: A device for inspecting a foreign substance, comprises a metal detector; and an X-ray foreign substance detector provided on the downstream side of the metal detector that receives X-rays irradiated to an article to generate an X-ray image and analyze the concentration distribution of configuration pixels of the X-ray image to detect foreign matters, and the device automatically specifies the concentration region for analyzing the concentration distribution, in response to the result detected by the metal detector. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a foreign matter inspection apparatus for inspecting the presence or absence of foreign matter in a product such as food.

  In the production line for food, etc., a metal detection device and an X-ray foreign material detection device are installed in order to inspect the presence or absence of foreign material in the product, and the product in which the foreign material is detected is discharged out of the line. Yes.

  The metal detection device forms a high-frequency magnetic field by the transmission coil, and inspects whether or not the metal foreign matter is mixed into the product conveyed by the conveyor based on the disturbance of the high-frequency magnetic field generated when the metal foreign matter passes through the high-frequency magnetic field. According to the metal detection device, generally, a highly harmful metal foreign object is reliably detected, but non-metal foreign objects such as rubber and bone are not detected, and a packaging material containing metal such as an aluminum vapor deposition film is used. About a product, a metal foreign material cannot be detected under the influence of this packaging material.

On the other hand, the X-ray foreign object detection device irradiates the product conveyed by the conveyor with X-rays, receives this with an X-ray sensor provided on the opposite side of the X-ray source, and based on the X-ray detection signal from the sensor, Inspecting the presence or absence of foreign matter in the product, not only metallic foreign matter but also non-metallic foreign matter such as rubber and bone can be detected. However, the metal itself is not detected, and the detection is performed using the difference in the X-ray transmittance between the product and the foreign material, so that the product is covered with a packaging material containing a metal such as an aluminum vapor deposition film, If the product contains non-metallic foreign matter whose X-ray transmittance is close, it is difficult to detect the foreign matter.
JP 2004-28768 A

  The present invention provides a foreign matter inspection apparatus capable of reliably detecting foreign matter mixed in a product, such as a production line where a product using a packaging material containing a metal such as an aluminum vapor deposition film and a product other than the product are mixedly produced. The purpose is to provide.

The invention according to claim 1 is a metal detector for detecting a metal contained in an article;
Provided on the downstream side of the metal detector, irradiates the article with X-rays, receives the irradiated X-rays, generates an X-ray image based on the received X-rays, and configures the X-ray image An X-ray foreign matter detector for detecting foreign matter mixed in the article by analyzing the density distribution of the pixels to be
According to a detection result of the metal detector, there is provided a foreign substance inspection apparatus that automatically sets a concentration region where the concentration distribution is analyzed.

When the metal detection by the metal detector is made, the invention according to claim 2 determines whether or not the detected metal is included in the packaging material,
The foreign substance inspection apparatus according to claim 1, wherein when it is determined that the metal is contained in the packaging material, the concentration region is set to a region suitable for metal detection.

The invention according to claim 3 determines whether or not the detected metal is contained in a packaging material when metal detection is performed by the metal detector.
3. The foreign matter inspection apparatus according to claim 1, wherein when it is determined that the metal is not contained in the packaging material, the concentration region is set to a region suitable for foreign matter detection other than metal.

  According to invention of Claim 1, there exist the following outstanding effects. According to the detection result by the metal detector, the detection accuracy by the X-ray foreign object detector can be improved by automatically setting the density region where the analysis of the density distribution of the X-ray image is performed.

  According to invention of Claim 2, in addition to the effect which invention of Claim 1 show | plays, there exist the following outstanding effects. When a metal-containing packaging material is detected, an X-ray foreign object detector performs detection specialized for metal foreign objects, so that metal foreign objects can be reliably detected even in products packaged with aluminum vapor deposited films or the like. it can.

  According to invention of Claim 3, in addition to the effect which invention of Claim 1 or 2 has, there exist the following outstanding effects. When a metal foreign object is detected, the X-ray foreign object detector performs detection specialized for a foreign object other than metal, so that it is possible to improve the detection accuracy of a foreign object other than metal that is normally difficult to detect.

  Embodiments of the present invention will be described below.

[Foreign substance inspection device 1]
FIG. 1 is an overall front view of a foreign matter inspection apparatus 1 according to the present embodiment. The foreign matter inspection apparatus 1 includes a metal detector 2 and an X-ray foreign matter detector 3, and a product that uses a packaging material containing metal such as an aluminum vapor deposition film, and a product that does not use such a packaging material. Is installed in the production line of food that is produced in a mixed flow, and the product is checked for foreign matter.

  The foreign object inspection apparatus 1 is provided on the downstream side of the metal detector 2 after the product (article) G to be inspected is transported in the direction of arrow A in FIG. 1 by the transport conveyor 21 of the metal detector 2. It is conveyed in the same direction by the conveyor 32 of the X-ray foreign matter detector 3. In addition, the height and conveyance speed of the conveyance surfaces 21a and 32a are prepared so that both the conveyance conveyors 21 and 32 can transfer the articles | goods G smoothly.

  The metal detector 2 and the X-ray foreign object detector 3 are interlocked, and the detection target by the X-ray foreign object detector 3 is automatically set according to the detection result of the metal detector 2. When a metal is detected by the metal detector 2, it is further detected (determined) whether the metal is contained in the packaging material or a foreign substance mixed in the article G.

  And when it is judged that the said metal is contained in the packaging material of the article | item G, the detection object by the X-ray foreign material detector 3 is specialized to a metal foreign material, and is the foreign material mixed in the inside of the article | item G. If determined, the detection target by the X-ray foreign matter detector 3 is switched so as to specialize non-metallic foreign matters such as rubber and bone.

[Metal detector 2]
As shown in FIG. 1, the metal detector 2 includes a transport conveyor 21, a metal detection unit 22, an article detection sensor 23, and a control unit 24 (not shown), and is continuously transported by the transport conveyor 21. The metal contained in the plurality of articles G is detected. The metal detection unit 22 is an annular body having a through hole 22a for allowing the article G conveyed by the conveyor 21 to pass through the conveyor 21 and transmitting a high-frequency magnetic field on the annular body. A coil 221 is provided, and receiving coils 222a and 222b are provided at the bottom.

  As shown in FIG. 1, the reception coils 222 a and 222 b are disposed symmetrically with respect to the center line CL of the transmission coil 221 and receive the same amount of magnetic flux from the high-frequency magnetic field generated by the transmission coil 221. When a metal passes through the high-frequency magnetic field, a difference occurs in the amount of magnetic flux received by the two receiving coils, and the metal is detected by the difference. In particular, when a ferrous metal that is a magnetic material passes, the magnetic flux generated by the magnetization of the metal itself is added to the magnetic flux of the high frequency magnetic field, and when a non-ferrous metal such as aluminum passes, its internal current The magnetic flux generated by the magnetic field cancels the magnetic flux of the high-frequency magnetic field, so that the high-frequency magnetic field is disturbed, and in either case, a difference occurs in the amount of magnetic flux received by the two receiving coils.

  The difference in the amount of magnetic flux received by the receiving coils 222a and 222b appears as a difference in the waveform of the internal current of both receiving coils, and based on this, a metal detection signal is generated by a signal circuit (not shown) provided in the metal detector. The The article detection sensor 23 is a photoelectric sensor provided on the upstream side of the metal detection unit 22, and detects the timing at which the article G passes the high-frequency magnetic field generated by the transmission coil 221.

  The control unit 24 controls each component of the metal detector 2 in accordance with an operator setting transmitted from the control unit 39 of the X-ray foreign object detector 3 described later, and detects the metal based on the metal detection signal. The presence or absence of a metal contained in the article G passing through the section 22 is detected. When the article G contains metal, the position and size of the metal in the article conveyance direction can be detected by combining the metal detection signal with the detection signal from the article detection sensor 23.

  In addition, when the position and size of the metal part included in the packaging material in the article conveyance direction is known in advance, the metal is packaged such as an aluminum vapor deposition film based on the detected position and size of the metal. Whether it is a material or a metal foreign object can be determined. For example, in the case where a bag made of aluminum on the entire surface is used as a packaging material, if the detected metal has a larger overall length than the product body, it is determined that the bag is a packaging bag, and the product body is sufficiently smaller than the food. Is determined to be a metallic foreign object. These detection results are transmitted to the control unit 39 of the X-ray foreign object detector 3.

[X-ray foreign matter detector 3]
As shown in FIG. 1, the X-ray foreign object detector 3 includes a casing 31, a conveyor 32, shielding curtains 33 and 34, an X-ray source 35, a line sensor 36, a display operation unit 37, an article detection sensor 38, and a control. The unit 39 (not shown) is provided, and the foreign matter mixed in the article G continuously conveyed by the conveyor 32 is detected by X-rays.

  The casing 31 is a cover body for shielding X-rays, and openings are formed on both side surfaces 31a and 31b for allowing the articles G conveyed through the conveyor 32 to pass therethrough. Has been. The shielding curtains 33 and 34 block the opening and prevent external leakage of X-rays.

  The X-ray source 35 is provided above the transfer conveyor 32 inside the housing 31 and irradiates the article G passing on the transfer surface of the transfer conveyor 32 with X-rays. FIG. 2 is a view of the periphery of the line sensor 36 as viewed from the article conveyance direction, and an X-ray intensity curve corresponding to this is displayed below the line sensor 36. The line sensor 36 is provided below the conveyance surface 32a of the conveyance conveyor 32, and includes a light receiving element 36a disposed in a direction orthogonal to the article conveyance direction, and the article G and the conveyor belt are transmitted through the light reception element 36a. Receives X-rays. As shown in FIG. 2, the received X-ray intensity is strongest in a portion that transmits only the conveying surface 32 a of the conveyor, is slightly weak in a portion that transmits the article G, and has a portion that transmits the foreign matter f. It becomes the weakest.

  The display operation unit 37 is a touch panel display, and allows the operator to perform setting input operations on the metal detector 2 and the X-ray foreign object detector 3, and the presence / absence of foreign objects in the article G and foreign objects in the article G Displays the position etc. The article detection sensor 38 is a photoelectric sensor similar to the article detection sensor 23 of the metal detector 2, provided on the upstream side of the line sensor 36, and detects the timing at which the article G passes the line sensor 36. The position where the foreign substance is mixed in the article conveyance direction is specified.

  The control unit 39 controls each component of the X-ray foreign object detector 3 according to the setting input by the operator from the display operation unit 37, and transmits the setting by the operator to the control unit 24 of the metal detector 2. 24, the detection result by the metal detector 2 is received. Further, the control unit 39 converts X-ray intensity data transmitted through the article G and received by the line sensor 36 into, for example, gradation data of 256 gradations in pixel units, and performs image processing to convert the X-ray intensity data. Generate an image.

  The X-ray image will be described according to the X-ray intensity curve shown in FIG. 2. The portion that transmits only the conveyor conveyance surface 32a is brightest (light), and the portion that transmits the article G is slightly dark (dark). ), And the portion that transmits the foreign substance f protrudes and becomes dark. Therefore, by analyzing the density in the X-ray image, that is, the density distribution of the pixels constituting the X-ray image, it is possible to detect the article and the foreign matter having a density different from that of the article.

  However, as shown in FIGS. 3 (a) and 3 (b), a packaging material containing metal is used because there is a small concentration difference between a packaging material containing metal and a metal foreign object, or an article that is food and a non-metal foreign object. It is difficult to detect metallic foreign matter and non-metallic foreign matter mixed in the product. Therefore, the control unit 39 provided in the foreign matter inspection apparatus 1 sets so as to narrow down the concentration region where the concentration distribution is analyzed in the X-ray foreign matter detector 3 according to the detection result by the metal detector 2, and By detecting foreign matter only in the concentration region, foreign matter that is difficult to detect as it is is reliably detected.

  More specifically, when it is determined that the metal detected by the metal detector 2 is included in a packaging material such as an aluminum vapor deposition film, the control unit 39 determines whether there is a metal-containing packaging material or metal foreign matter. The density region (R1 in FIG. 3A) is set to the full range, and conversion to 256-tone light and shade data and image processing are performed using only the X-ray intensity data included in this density region. Thereby, it becomes easy to distinguish the packaging material from the metal foreign object, and the metal foreign object can be reliably detected even in a product that uses the metal-containing packaging material.

  Further, when the metal detected by the metal detector 2 is determined to be a foreign object, the control unit 39 displays a concentration region (R2 in FIG. 3B) corresponding to the food that is the article body or the non-metallic foreign object. As a full range, conversion to 256-level grayscale data and image processing are performed using only X-ray intensity data included in this density region. This makes it easy to distinguish between the article main body and the non-metallic foreign matter, and in addition to the metallic foreign matter, it is possible to increase the detection accuracy related to the non-metallic foreign matter such as rubber that is usually difficult to detect. In addition, even when metal is not detected by the metal detector 2, the non-metallic foreign matter that is not detected by the metal detector 2 is reliably detected with the concentration region corresponding to the food or non-metallic foreign matter as the article body as a detection target. To do.

  The control unit 39 instructs a sorting device (not shown) disposed on the downstream side of the X-ray foreign matter detector 3 to sort the articles G in which foreign matter has been detected and discharge them out of the line. The detection result obtained by the detector 2 and the detection result obtained by the X-ray foreign matter detector 3 are integrated, and the display unit 37 displays the position of the foreign matter mixed in the article G. By referring to this display, the operator can take out and discard only the part where foreign matter is mixed from the articles discharged out of the line.

[Characteristics of Foreign Object Inspection Device 1]
The foreign matter inspection apparatus 1 according to the embodiment is provided on the downstream side of the metal detector 2 that detects the metal contained in the article and the metal detector 2, and irradiates the article with X-rays and the irradiated X-rays. X-ray foreign matter detector 3 that detects foreign matter mixed in the article G by generating an X-ray image based on the received X-ray and analyzing the density distribution of the pixels constituting the X-ray image. And, according to the detection result by the metal detector 2, the concentration region in which the concentration distribution is analyzed is automatically switched and set, thereby enabling the detection accuracy by the X-ray foreign object detector The excellent effect that it can be improved is exhibited.

  In addition, the foreign substance inspection apparatus 1 according to the above embodiment determines whether or not the detected metal is included in a packaging material such as an aluminum vapor deposition film when metal detection is performed by the metal detector 2. When it is determined that the metal is included in the packaging material, the density region where the analysis of the density distribution of the X-ray image is performed is set to a region R1 suitable for metal detection. Even in products that are packaged in the same manner, a highly harmful metal foreign matter can be reliably detected.

  Furthermore, the foreign substance inspection apparatus 1 according to the above embodiment determines whether or not the detected metal is contained in a packaging material such as an aluminum vapor deposition film when metal detection is performed by the metal detector 2. When it is determined that the metal is not contained in the packaging material, the density region where the analysis of the density distribution of the X-ray image is performed is set to a region R2 suitable for detecting foreign matter other than metal. In addition to the metallic foreign matter, it is possible to improve the detection accuracy of foreign matters other than metals that are usually difficult to detect.

[Modification of the above embodiment]
In the above embodiment, in order to narrow down the density area to be detected by the X-ray foreign matter detector 3, only the intensity data of the X-rays included in the predetermined density area R1 or R2 is targeted, and the grayscale data of 256 gradations is used. Although the conversion processing is performed, the X-ray intensity data included in all density regions is processed, for example, after conversion to 1024 grayscale data, only a predetermined density region is extracted and the foreign matter is extracted. It may be detected.

  In the above embodiment, the operator removes the foreign matter while referring to the foreign matter mixing position displayed on the display operation unit 37. However, it is difficult to accurately specify the foreign matter mixing position in the actual product. It is also difficult to remove only. Therefore, a projector for projecting an image downward is installed above the downstream side of the X-ray foreign matter inspection machine 3, the conveyance conveyor 32 is stopped when the foreign matter is detected, and the inspection result is adjusted to the position and size of the corresponding article G. Project an image. By displaying the mark of the foreign substance mixing position on the inspection result image, the foreign substance mixing position is specified in the actual product, and the removal work limited to only the foreign substance mixed portion can be easily performed.

  In the above-described embodiment and the above-described modification, when displaying the foreign substance mixing position, the article to be inspected is divided into a plurality of equal areas from the beginning to the end in the conveyance direction, with a boundary in the direction orthogonal to the conveyance direction. It may be displayed whether there is a foreign object in the area. Alternatively, a rectangular area including an article may be divided into a lattice shape with a boundary between the conveyance direction and a direction orthogonal thereto, and it may be displayed in which divided area there is a foreign object. As described above, the article can be cut along the boundary, and only the foreign matter-mixed portion can be easily removed. In addition, since the boundary portion of each area is linear, it is possible to automatically cut the area where the foreign object is detected by providing a mechanism for cutting the article at the article outlet of the apparatus. .

  In addition, the foreign substance inspection apparatus of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

1 is an overall front view of a foreign matter inspection apparatus according to an embodiment. The figure explaining the detection principle of a X-ray foreign material detector. The figure explaining the setting of the density | concentration area | region made into a test object in the foreign material inspection apparatus which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foreign material inspection apparatus 2 Metal detector 21 Conveyor 22 Metal detection part 3 X-ray foreign material detector 32 Conveyor 35 X-ray source 36 Line sensor 36a Light receiving element 37 Display operation part G Goods

Claims (3)

A metal detector for detecting the metal contained in the article;
Provided on the downstream side of the metal detector, irradiates the article with X-rays, receives the irradiated X-rays, generates an X-ray image based on the received X-rays, and configures the X-ray image An X-ray foreign matter detector for detecting foreign matter mixed in the article by analyzing the density distribution of the pixels to be
A foreign matter inspection apparatus, wherein a concentration region in which the concentration distribution is analyzed is automatically set according to a detection result by the metal detector. When metal detection is performed by the metal detector, it is determined whether the detected metal is contained in a packaging material,
The foreign matter inspection apparatus according to claim 1, wherein when it is determined that the metal is included in the packaging material, the concentration region is set to a region suitable for metal detection. When metal detection is performed by the metal detector, it is determined whether the detected metal is contained in a packaging material,
3. The foreign matter inspection apparatus according to claim 1, wherein when it is determined that the metal is not contained in the packaging material, the concentration region is set to a region suitable for foreign matter detection other than metal.

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