JP2005083877A - Method and apparatus for detecting shift of lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift-of-lid detector certainly detecting shift-of-lid of an article inspected wherein the opening of a food container is closed by a lid, and also to provide a shift-of-lid detecting method. <P>SOLUTION: In the shift-of-lid detecting method, the lid of the article 1 to be inspected, wherein the opening of the food container 2 is closed by the lid 4, is irradiated with light from the rear side of the lid and the transmitted light from the lid is split by a half mirror 12 while the transmitted light of the half mirror is imaged by a first camera 13 and the reflected light of the half mirror is imaged by the first camera and, a second camera 14 in a different aperture, a different exposure time or a different incident light quantity from that of the first camera. Both of (a) lid edge reflection brightly looked of the peripheral edge of the lid of the article and (b) the shift of the lid are imaged by either one of the cameras and the image of the other camera for imaging only (a) lid edge reflection is substrated from the image of one camera to calculate the brightness of the peripheral edge of the lid. The presence of (b) the shift of the lid is decided from the brightness of the peripheral edge of the lid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lid displacement detection device and a lid displacement detection method for detecting a displacement of a lid in an article to be inspected in which an opening of a colored food container containing, for example, jelly or the like is closed with a lid made of aluminum foil or the like. Lid displacement detection that can prevent a non-defective product from being mistakenly rejected as a defective product by detecting that there is a misalignment even though there is no misalignment of the lid with respect to the food container. The present invention relates to a device and a lid slip detection method.

2. Description of the Related Art Conventionally, articles to be inspected in which food containers are filled with contents such as jelly and the opening is closed with a lid have been provided. FIG. 1 is a view showing an example of this type of article to be inspected. FIG. 1 (a) is a plan view and FIG. 1 (b) is a side view. The article to be inspected 1 is heat-sealed in a cup-shaped plastic food container 2 provided with a ring-shaped flange portion 3 extending in the radial direction at the upper end and the opening thereof. And a lid 4 made of a sheet material such as aluminum foil. In this inspected article 1, after filling the food container 2, the lid 4 is placed on the flange portion 3 and heat-sealed. The periphery of the lid 4 is welded to the upper surface of the flange portion 3, and the opening of the food container 1 is sealed. Manufactured by doing.
In the manufacture of the article to be inspected 1, as shown in FIG. 2, when heat sealing is performed with the position of the lid 4 being shifted with respect to the flange portion 3 of the food container 2, the lid 4 is placed on the opening side periphery of the article to be inspected 1. As a result, an exposed portion 5 not covered with is produced. Such a lid slipping defective product has insufficient sealing performance of the food container 2, and the contents spill out from the gap 6 or cause a problem of deterioration. Therefore, the lid slipping defective product is excluded from the production line. There is a need. Conventionally, inspectors have been visually inspected in order to detect the defective lid slip and remove it from the production line, but this inspection requires a large number of inspectors during mass production, and costs such as labor costs. However, there are problems such as increased bulk and limited inspection accuracy.
As an inspection method that replaces the visual inspection, there has been proposed a technique for detecting the positional deviation of the lid with respect to the food container by irradiating the food container and the lid with light from a single light source below (for example, by imaging) , See Patent Document 1).
In addition, as an imaging device, an imaging lens, a dividing unit that divides light incident from the imaging lens, a light transmission filter into which the divided light from the dividing unit is incident and different in light transmittance, and the light transmission filter There has been proposed a multi-plate image pickup apparatus including an image pickup means on which an optical image from each image is formed and a video signal processing means for deriving an output of the image pickup means (see, for example, Patent Document 2). .
JP-A-7-128016 JP 7-298276 A

  However, since the prior art described in Patent Document 1 irradiates light from a single light source below, it can be used with high precision for transparent food containers (transparent cups) that easily transmit light. However, the accuracy tends to be slightly reduced for food containers (colored cups) that are colored such that red or brown light is hardly transmitted.

Regarding the colored cup, a method of transmitting light through the colored cup by using a plurality of high-luminance halogen lamps, metal halide lamps, and the like and irradiating from a plurality of directions obliquely below the colored cup can be considered. If this method is used, even if it is a colored cup, the position shift detection of the lid | cover which permeate | transmitted light is attained. FIG. 3 is a diagram showing an example of lid displacement inspection using such transmitted light. This image is irradiated from a plurality of oblique directions at the lower part of the colored cup, and the upper part of the cup is imaged from the camera placed above. And the state which detected the slippage of the lid is shown. In this case, the exposed portion 5 that is not covered with the lid 4 has a brighter portion wider than the normal portion, and the presence or absence of lid displacement can be determined by detecting this.
However, in this case, as indicated by reference numeral 7 in FIG. 3, the irradiated light may be reflected by the lid edge due to the shape of the lid edge even in a normal part without lid displacement, and may appear to be shining strongly (the lid edge reflecting portion). 7) As a result, there is a possibility that a non-defective product may be mistaken for a defective lid displacement.

  In the conventional method, when the food container 2 is a colored cup that does not easily transmit light, as described above, it is necessary to irradiate strong light or to increase the exposure time of the camera. When a strong light is applied, a phenomenon such as smearing or blooming occurs in a normal CCD camera, and even pixels in the vicinity of the pixel receiving strong light are affected, and light blur occurs in a digital image. As a result, the width of the normal part that is shining is larger than the width of the light that is actually shining. is there.

Although a CCD camera with a wide dynamic range suitable for this kind of imaging is sold for surveillance, an FA (shutter type) camera is not commercially available and is expensive even if it is available. Therefore, there is a problem that the lid displacement detection device becomes expensive and difficult to put into practical use.
A CMOS camera has a wider dynamic range than a CCD camera, but has a large variation in the dynamic range of each pixel and is not suitable for measurement. There are also problems such as more noise than CCD cameras.
Further, in the detection method, a method of taking two pictures by changing the exposure of the camera is conceivable, but it is difficult to take an image from the same angle accurately by shifting the time because the subject flows on the conveyor. .
The technique described in Patent Document 2 can obtain wide dynamic range image data as a result of simultaneously capturing images with different exposures, but has not yet completed the lid displacement inspection. Moreover, such a general-purpose image processing apparatus has not been commercialized.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lid slippage detection device and a lid slippage detection method capable of reliably detecting a lid slippage defect of an article to be inspected in which an opening of a food container is closed with a lid.

  In order to achieve the above object, the present invention provides a transmission illumination that irradiates light from the back side of the lid of an article to be inspected with the opening of the food container covered with a lid, and a half mirror provided above the article to be inspected. The first camera arranged at a position where the transmitted light that has passed through the half mirror is incident, and the first camera arranged at a position where the light reflected by the half mirror is incident, and the aperture or exposure time of the first camera Alternatively, the second camera in which the amount of incident light is changed, and image signals from the first camera and the second camera are input, and the outer peripheral edge of the article to be inspected appears bright (a) lid edge reflection and (b ) From the image of either camera that captures both of the lid displacements, the brightness of the lid periphery obtained by subtracting the image of either one of the other cameras that images only the lid edge reflection (a) Judgment of presence / absence of lid displacement Provides a lid deviation detection apparatus characterized by comprising an image processing apparatus for outputting a signal if.

  The present invention also irradiates light from the back side of the lid of the article to be inspected with the opening of the food container closed with a lid, divides the transmitted light with a half mirror, and images the transmitted light of the half mirror with a first camera. Then, the reflected light of the half mirror is imaged with the first camera and the second camera with the aperture or the exposure time or the incident light quantity changed, and appears bright in the lid periphery of the article to be inspected. (B) From the image of one of the cameras that captures both of the lid displacements, from the brightness of the lid periphery obtained by subtracting the image of either of the other cameras that captures only (a) the lid edge reflection, the (b) lid Provided is a lid displacement detection method characterized by determining the presence or absence of displacement.

  According to the present invention, light is irradiated from the back side of the lid of the article to be inspected, the transmitted light is divided by the half mirror, and the transmitted light and reflected light of the half mirror are divided by two cameras having different apertures or exposure times. And (a) only the lid edge reflection from the image of either camera that images both the lid edge reflection and (b) lid displacement. From the brightness of the lid periphery obtained by subtracting the image of the other camera to be imaged, (b) because it determines the presence or absence of lid displacement, misrecognize lid edge reflections that occur in normal parts that are not lid displaced as lid displacement, The malfunction that eliminates non-defective products can be eliminated, and the inspection accuracy of defective products can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 4 is a diagram showing an embodiment of a lid displacement detection device according to the present invention. The lid displacement detection device 10 transmits transmitted light 11 that irradiates light from the back side of the lid 4 of the article 1 to be inspected, a half mirror 12 provided above the article 1 to be inspected, and the half mirror 12. The first camera 13 disposed at the position where the transmitted light is incident and the position where the light reflected by the half mirror 12 is incident, and the aperture, exposure time, or incident light amount are changed from those of the first camera 13. The image signals of the second camera 14 and the first camera 13 and the second camera 14 are inputted, and appear bright in the periphery of the lid 4 of the article 1 to be inspected. (A) Lid edge reflection and (b) Lid (B) The presence / absence of a lid displacement is determined from the brightness of the lid periphery obtained by subtracting the image of either one of the cameras capturing only the lid edge reflection from the image of either camera that captures both of the displacements. If there is a lid slip It has a configuration in which an image processing apparatus 15 for outputting a degree.

  A plurality of the transmitted illuminations 11 are provided obliquely below the food container 2. These transmitted illuminations 11 are transmitted through the food container 2 colored in red, brown or the like in the exposed portion 5 where the irradiation light is displaced from the lid, and the cameras 13 and 14 disposed above the article 1 to be inspected. High-intensity halogen lamps and metal halide lamps that can obtain sufficient light for imaging are used.

  In the present invention, when a half mirror 12 that can split incident light into transmitted light and reflected light with an optical power ratio of about 1: 1 is adopted, the first camera 13 and the second camera 14 The imaging target of both cameras can be made different by giving a difference to the aperture or exposure time. In addition, as the half mirror 12, one that can be divided with a difference in the amount of transmitted light and reflected light is adopted, and the imaging target can be made different by making a difference in the amount of incident light of both cameras.

  The first and second cameras 13 and 14 can be CCD cameras, and can be used by appropriately selecting from various commercially available products. In the implementation of the present invention, the first camera 13 and the second camera 14 change their respective apertures, exposure time, or incident light quantity, and any one of the cameras looks bright in the periphery of the lid 4 of the article 1 to be inspected. Both (a) lid edge reflection and (b) lid displacement can be imaged, and the other camera is used by setting (a) only lid edge reflection. Of the (a) lid edge reflection and (b) lid displacement, (a) lid edge reflection is a stronger light, and (b) the lid displacement is weaker than that, the imaging portion of the lid 4 and the conveyor 16 ( The lightness (intermediate part) is intermediate between (dark part) and (a) lid edge reflection (bright part).

  The image processing device 15 uses (a) an image of one camera that captures only lid edge reflection from an image of either camera that captures both (a) lid edge reflection and (b) lid displacement. (B) is used to determine whether or not there is a cover slippage and to output an operation signal (exclusion signal) to the reject device provided in the conveyor 16 when it is determined that the cover slips. The image processing device 15 can be used by appropriately selecting from various commercially available products, and can be used with some improvements to the commercially available devices.

  This lid displacement detection device 10 is filled with contents such as jelly in a food container 2, and a sheet-like lid 4 such as an aluminum foil is placed on the flange portion 3 for heat sealing and sealed and packaged. It is provided on a conveyor 16 that carries the article 1. The filling / sealing packaging apparatus for manufacturing the article 1 to be inspected is not particularly limited. Further, the conveyor 16 that carries out the article 1 to be inspected is provided with an exclusion device that is driven when an exclusion signal is output from the image processing device 15 and that excludes the article 1 to be inspected 1 on the conveyor 16 from the conveyor 16. ing. As this exclusion device, for example, a device configured to push out the article 1 to be inspected, which has been determined to have a lid displacement by reciprocating a lever, from the conveyor 16 is used.

Next, a lid displacement detection method according to the present invention will be described. The lid slip detection method of the present invention can be carried out using the lid slip detection device 10 configured as shown in FIG.
In the lid displacement detection method of the present invention, light is irradiated from the back side of the lid 4 of the article 1 to be inspected, the transmitted light is divided by the half mirror 12, and the transmitted light of the half mirror 12 is imaged by the first camera 13. Then, the reflected light of the half mirror 12 is picked up by the second camera 14 with different aperture or exposure time or incident light quantity, and appears bright in the periphery of the lid of the article 1 to be inspected. (A) Lid edge reflection and (b) Lid (B) The presence / absence of lid displacement is determined from the brightness of the lid periphery obtained by subtracting the image of either one of the cameras capturing only the lid edge reflection from the image of either camera that captures both of the displacements. To do.

  In the example shown in FIG. 4, the first camera 13 has a dark exposure, and the second camera 14 obtains an image with a bright exposure. In this lid displacement inspection, the first camera 13 has the strongest light. (A) The exposure setting is set so that imaging can be performed without blurring the lid edge reflection. In the first camera 13, (b) it is impossible to distinguish between an intermediate portion indicating lid displacement and a dark portion (the upper surface of the lid 4 and the upper surface of the conveyor 16). On the other hand, the second camera 14 is set to an exposure that allows separation of the intermediate portion and the dark portion.

  The portion that appears to shine in the image of the first camera 13 is limited to the (a) lid edge reflecting portion where the illumination is reflected on the lid edge (except for the case of a transparent cup for a colored cup). Edge reflection means that the lid 4 sufficiently covers the flange portion 3 and it can be determined that no sealing failure has occurred.

  The parts that appear to shine in the second camera 14 are both (a) a lid edge reflecting part and (b) a lid slipping part.

  In the image processing, (b) an intermediate position indicating lid displacement at an outer peripheral position obtained by subtracting a portion of the image captured by the first camera 13 from the portion of the image captured by the second camera 14 that is shining. If it is determined that there is a lid displacement, an exclusion signal is output from the image processing device 15 to the exclusion device of the conveyor 16. The article 1 to be inspected determined to have a lid slip is removed from the conveyor 16.

According to the present invention, light is irradiated from the back side of the lid 4 of the article 1 to be inspected, the transmitted light is divided by the half mirror 12, and the two cameras 13, 14 having different apertures or exposure times or incident light amounts are used. The image of the transmitted light and the reflected light of the half mirror 12 are separately captured, and (a) the lid edge reflection and (b) the lid displacement of either one of the cameras that appear bright in the peripheral edge of the lid of the article 1 to be inspected. Since (a) the brightness of the lid periphery obtained by subtracting the image of the other camera that captures only the lid edge reflection from the image, (b) the presence / absence of lid displacement is determined, so that it occurs in a normal part that is not displaced. It is possible to improve the inspection accuracy of a product with defective lid displacement by eliminating a malfunction in which the lid edge reflection is misidentified as a lid displacement and excluding a non-defective product.
Hereinafter, the effects of the present invention will be demonstrated by examples.

A lid displacement detection device having the configuration shown in FIG. 4 was produced. the detail is right below.
・ Transparent illumination; Number of units = 4 units.
Light source: KTX 35MT (35 W) x 4 manufactured by Kenko.
Fiber: Kenko Co., Ltd., FG8L-1000F W50R (with condensing lens) x4.
・ Camera: Sony XC-55.
-Half mirror; manufactured by Koshin Kogaku Kogyo Co., Ltd., 50 × 50 mm square, optical power ratio 1: 1.
First camera setting: Aperture 8.
Second camera setting: Aperture 4
As the image processing apparatus, an image processing apparatus RV5000 manufactured by Nidec Tosok Corporation was used, and the output lines of the two CCD cameras were connected to the image processing apparatus.

As an article to be inspected, water was poured into a shrimp brown resin cup with a 90 mm caliber flange, and a lid made of aluminum foil was placed on the flange part and heat sealed.
This article to be inspected was placed on a conveyor and conveyed, and 5000 articles to be inspected with a conveyor speed of 40 m / s and a capacity of 4500 pieces / hour were inspected. As a result, it was possible to detect three defective lid displacement products having a displacement width of 2 mm and a displacement section of 50 mm. There was no misdelivery of non-defective products, and it was demonstrated that this lid displacement detector can perform lid displacement inspection with extremely high accuracy.

An example of the article to be inspected for the presence or absence of lid displacement is shown, (a) is a plan view and (b) is a side view. It is a top view which illustrates the to-be-inspected article with a lid shift. It is a figure which illustrates the state of lid deviation imaged by the lid deviation detection apparatus. It is a lineblock diagram showing one embodiment of a lid gap detecting device concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Article to be inspected, 2 ... Food container, 3 ... Flange part, 4 ... Cover, 5 ... Exposed part, 6 ... Gap, 7 ... Cover edge reflection part, 10 ... Cover displacement detection apparatus, 11 ... Transmitted illumination, 12 ... Half mirror, 13 ... first camera, 14 ... second camera, 15 ... image processing apparatus, 16 ... conveyor.

Claims (2)

  Transmitted illumination that irradiates light from the back side of the lid of the article to be inspected with the opening of the food container closed with a lid, a half mirror provided above the article to be inspected, and transmitted light that has passed through the half mirror is incident A first camera arranged at a position where the light is reflected by the half mirror, and a second camera arranged at a position where the light reflected by the half mirror is incident, and the aperture, exposure time, or incident light quantity is changed. The image signals of the first camera and the second camera are inputted, and either one of the two (a) the lid edge reflection and (b) the lid displacement that looks bright in the lid periphery of the article to be inspected is imaged. (B) The presence or absence of lid displacement is determined from the brightness of the lid edge obtained by subtracting the image of either one of the other cameras that captures only the lid edge reflection from the image of (b). Is an image processing device that outputs signals Lid deviation detection apparatus characterized by comprising and. Light is irradiated from the back side of the lid of the article to be inspected with the opening of the food container covered with a lid, the transmitted light is divided by a half mirror, and the transmitted light of the half mirror is imaged by the first camera. The reflected light is imaged with the first camera and the second camera with the aperture or exposure time or incident light quantity changed, and appears bright in the periphery of the lid of the article to be inspected. (A) Lid edge reflection and (b) Lid displacement (B) The presence or absence of lid displacement is determined from the brightness of the lid periphery obtained by subtracting the image of either one of the other cameras that captures only the lid edge reflection from the image of either camera that captures both. A lid misalignment detection method characterized by:

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