JP2020125972A - Package inspection means - Google Patents

Abstract

To provide means for inspecting a heat seal part of a package whose circumferential edges are packaged with heat seal, the heat seal constituting a row of lattice points and, more specifically, provide inspection means which can acquire a heat seal image with few mirror reflections and inspect for insufficient biting of a content, inclusion of foreign matter, and defects such as scratches or wrinkles quickly with high accuracy.SOLUTION: Inspection means 1 comprises two polarization filters 13, 22, and allows a lattice point image in which a heat seal part of a powder wrapping sheet 100 is reflected to be acquired with few mirror reflections. A light and dark striped cyclic pattern is acquired from the lattice point image, and when the light or dark part constituting the striped cyclic pattern exceeds a prescribed threshold width, it is determined that the heat seal part is defective.SELECTED DRAWING: Figure 1

Description

The present invention relates to a means for inspecting a heat-sealed portion of a package, the periphery of which is packaged by heat-sealing and which forms lattice points where the heat-sealing is arranged. More specifically, the image of the heat seal is acquired with a small amount of specular reflection, and it is accurately and quickly inspected whether the contents are caught, foreign matter is mixed, scratches or wrinkles are not generated. The inspection means that can be performed.

The packaging body whose peripheral edge is heat-sealed is provided with an inspection step for inspecting the outer appearance between the heat-sealing step and the packaging step such as box packaging while the package is conveyed by a conveyor. In the inspection process, the heat-sealed portion is photographed while irradiating with light, and the photographed image is analyzed to inspect whether the contents are caught, foreign matter such as hair is mixed, or scratches are generated. ..

However, depending on the material of the package, it may be difficult to obtain a clear image of the heat-sealed portion in a part of the image captured by the specular reflection light from the surface of the package. For example, as a packaging sheet for powdered medicines, a sheet body made of aluminum foil is used so that the medicines are not deteriorated by light. Aluminum foil tends to specularly reflect light, making inspection of the heat-sealed part difficult.

The manufacturing process of the packaging sheet 100 and the reason why a defect occurs in the heat-sealing portion 101 will be briefly described below by taking a packaging sheet of powder and granules as an example. FIG. 8A shows the packaging sheet 100 heat-sealed on four sides, and FIG. 8B shows the packaging sheet 200 heat-sealed on three sides. FIG. 8(C) shows a state in which the heat-sealing portion forming the boundary edge portion of the adjacent packaging sheets has a defective powder particle entrapment (hereinafter referred to as powder entrapment). Each heat seal portion 101 is provided with grid points 102 arranged side by side by heat sealing (see FIG. 8C).

In the packaging sheet, two laminated sheet bodies are superposed and heat sealed on four sides, and one laminated sheet body is folded and three sides are heat sealed (FIG. 8(A)). (See FIG. 8B). In any case, while feeding the laminated sheet body for encapsulating the powder and granules (see the arrow in FIG. 8A), the longitudinal edge portion 103 is continuously heat-sealed along the feeding direction. ing. Then, a powdery or granular material supply nozzle is inserted from the rear end of the cylindrical laminated sheet body, and a predetermined amount of the powdery or granular material is intermittently supplied.

While the supply of the granular material is stopped, the boundary edge portion 104 with the adjacent packaging sheet is intermittently heat-sealed, and the packaging sheet filled with the granular material to be taken at one time is Being manufactured. As described above, in the packaging sheet, the powder granule supplying step and the heat-sealing step of the boundary edge portion 104 are intermittently repeated, so that the powder seal 105 may be generated in the heat-sealing portion. (See FIG. 8C).

The powder biting is likely to occur when the packaging sheet is manufactured for a long time or in an aged manufacturing machine. Specifically, when the powder or granules adhering to the opening edge of the supply nozzle of the powder or granules fall during the heat sealing step due to vibration or the like and are sandwiched between the heat sealing parts, etc. ..

The occurrence rate of powder bites varies depending on the degree of deterioration of the production line, the particle size of the granules, environmental conditions such as humidity and temperature, but if the occurrence rate is low, 0 to several pieces per day Is. On the other hand, if the occurrence rate is high, 10% or more of the products may be bitten. When powder biting occurs, the quality of the filled powder or granules may be impaired, and in the case of chemicals in particular, there is a strong demand to exclude defective products with high accuracy.

However, since the powdered medicine has a small particle size, even if it is bitten into the heat-sealed portion, only a slight protrusion appears on the surface of the package. Further, in the heat seal, when the base material is welded, processing marks corresponding to the streak-like portions and the convex-like portions carved on the sealer surface appear. Some of the processing marks have lattice points arranged periodically. In this case, the protrusions due to powder entrapment are mixed into many lattice points, so there is a problem that the defective portion cannot be inspected with high accuracy in the state where the image of the heat seal portion has specular reflection. It was

The packaging sheets for medicines differ mainly in the number of consecutive packaging depending on the number of times of daily administration, but there are mainly three-packaging three-packaging or two-packing two-packaging. This continuous packaging sheet produced 50 to 100 sheets per minute, and the usable time for inspection was limited to a short time. Therefore, there is a demand for an inspection device that can perform inspection with high accuracy and quickly.

Patent Document 1 discloses a technique of a packaging sheet inspection method and apparatus capable of accurately detecting the position of the packaging sheet in a captured image and performing a good inspection. According to the technique described in Patent Document 1, the analysis of the captured image extracts the change in the brightness of the image, and extracts only the periodic component of the brightness change due to the unevenness of the seal portion of the packaging sheet.

In detail, the average value of brightness in a fixed width is obtained along the seal line, and the average value data is converted into one-dimensional data. That is, the change in the brightness of the sticker is digitized, and the digitized data is further converted into waveform data (see FIG. 6C of Patent Document 1). The waveform data is subjected to a digital filter that passes the cycle of the brightness change due to the seal eyes to remove the influence of the seal eyes and detect the fluctuation of the overall brightness of the seal portion. Since the brightness of the defective seal portion changes abruptly, it is said that the defective portion can be specified by detecting the amount of change (see FIG. 6D of Patent Document 1).

However, in the technique described in Patent Document 1, the sheet body is only uniformly illuminated by the fluorescent lamps provided at two positions, ie, the downstream side and the upstream side in the transport direction, and the sheet is received by the imaging means. It was not possible to reduce the specularly reflected light. When the specular reflected light is reflected, the captured image loses the gradation of color and is whitened, that is, a portion in which the brightness sharply changes. Then, depending on the technique described in Patent Document 1, there is a problem that a change in brightness that sharply becomes bright due to specular reflection light may be erroneously detected as a change in brightness due to a defect.

Patent Document 2 discloses a technique of an inspection device capable of suppressing deterioration in accuracy of appearance inspection of an article due to specular reflection. According to the technique described in Patent Document 2, it is said that a plurality of images captured by a camera are combined and the reflection of light emitted by the illumination device due to specular reflection is removed. It is said that the image processing unit synthesizes a plurality of images captured at a plurality of timings with respect to an article conveyed by a conveyor by using a portion where light due to specular reflection is not reflected.

However, in a packaging production line where the transportation speed is fast, the packaging is likely to be vibrated during transportation, and in the images captured at a plurality of timings, there is a deviation in the reflection position of the packaging, the inclination of the packaging, or the like. It is easy to happen. Then, even if an image without specular reflection is to be combined from a plurality of images, it is not possible to combine the minute grid points forming the heat seal part with high accuracy, and the heat seal part is inspected with high accuracy. There was a problem that I could not do it.

Patent Document 3 discloses a technique of a highly accurate measurement method and apparatus for uneven gloss, which quantitatively measures uneven gloss on the surface of a paper product as one item of quality. According to the technique described in Patent Document 3, the incident light and the reflected light are passed through a polarization filter having the same phase with respect to the light source for inspection, so that the diffuse reflected light is blocked and the specular reflected light is transmitted, resulting in uneven gloss. It is said that it can be emphasized more.

In the image analysis processing, it is said that the original image is subjected to a two-dimensional Fourier transform, and then a specific wavelength range that can be recognized by the naked eye when the inverse Fourier transform is performed is multiplied by an emphasis coefficient to emphasize the unevenness of the image. Then, it is said that the image area of the bright part or the dark part forming the closed section is calculated separately as the uneven gloss part, and the product of the average area and the standard deviation of the area is output as the measurement result from the distribution parameter of the area. ing.

However, according to this technique, both the light source and the image pickup means allow specular reflection light, that is, specular reflection light, to pass through by the polarization filter. Then, the image of the heat-sealed portion cannot be acquired in the state where the specular reflection is small, and the defect of the heat-sealed portion cannot be inspected with high accuracy. Further, since this is a technique for determining the unevenness of the entire surface by calculating the area of the bright part or the dark part, there is a problem that it cannot be applied to the inspection of the lattice points forming the heat-sealed part limited to a minute range.

Patent Document 4 discloses a technique of a displacement measuring device that measures a displacement of an inspection target by imaging a displacement measurement grating provided at a predetermined position together with the inspection target. In Patent Document 5, the inspection target is irradiated with light via an imaging lens having a lattice pattern, and the inspection target is projected with the lattice pattern. A technique of a shape measuring device for measuring the is disclosed. In the techniques described in these, there is an example in which Fourier transform or moire processing is performed when determining the displacement amount from the image of the lattice arranged in the vicinity of the inspection target or the image of the lattice pattern projected on the inspection target. It is disclosed.

However, in any of the technologies, it is an essential requirement that the inspection target be photographed in a state in which the lattice pattern is superimposed. Since the position hidden by the grid is not reflected in the captured image, it was necessary to capture the inspection target multiple times and combine the images. Then, the techniques described in Patent Documents 4 and 5 are, like the technique described in Patent Document 2, not suitable for inspecting the heat-sealed portion of the package conveyed at high speed.

Patent Document 1: Japanese Patent Laid-Open No. 2003-291929 Patent Document 2: Japanese Patent Laid-Open No. 2015-59863 Patent Document 3: Japanese Patent Laid-Open No. 8-297099 Japanese Patent Document 4: Japanese Patent Laid-Open No. 2011-174874 Patent Document 5: Japanese Patent Laid-Open No. No. 2014-153287

The problem to be solved by the present invention is to provide a means for inspecting a heat-sealed portion of a package in which the periphery is packaged by heat-sealing and the heat-sealing forms a lattice point. More specifically, the image of the heat seal is acquired in a state where the specular reflection is small, the content is defectively caught, the defect due to the mixing of the foreign matter, the scratch, the wrinkles and the like are accurately generated, and, It is to provide an inspection means that can inspect quickly.

The inspection means according to the first aspect of the present invention is an inspection means for a heat-sealed portion of a package in which a peripheral edge is packaged by heat-sealing, and the heat-sealed portions form a lattice point, and the heat-sealed portion is The irradiation means includes irradiation means for irradiating light, photographing means for photographing the heat seal part, and judgment means for judging the state of the heat seal part, wherein the irradiation means is one direction passing through the first polarization filter. Of light having a wavelength of 10 μm is applied to the heat seal part, and the image capturing means passes the second polarization filter to acquire an image, and the polarization directions of the first polarization filter and the second polarization filter are not orthogonal to each other. The image of the lattice points reflected by the heat seal portion is acquired in a state where the specular reflection is small, and the determination unit includes a striped determination pattern acquisition unit and a defect determination unit, and the striped determination pattern. The obtaining means obtains a light and dark striped periodic pattern consisting of only lightness from the image of the lattice points, and the defect determination means, the bright portion or the dark portion of the striped periodic pattern is out of a predetermined threshold width. In this case, it is characterized in that it is determined that the heat seal portion is defective.

The heat sealing means that the base material including the welding film layer is welded with a heating sealer, an ultrasonic sealer, or the like. In heat sealing, when welding the base material, a processing trace corresponding to a streak portion or a convex portion carved on the sealer surface appears. The lined-up lattice points are processing marks that are periodically arranged so that the dot portions form a lattice. The arrangement direction of the lattice points is not limited to the case where the lattice points are arranged along the extending direction of the heat seal portion, and may be arranged in a direction intersecting the extending direction of the heat seal portion. The heat seals may be arranged concentrically.

The heat-sealing portion to be inspected is not limited to the heat-sealing portion of the packaging sheet in which the granular material is enclosed, and may be a heat-sealing portion between a resin container and a lid. The type of defect to be inspected may be any of powder particles, foreign matter, scratches, wrinkles on the substrate, etc., and is not limited. The material of the base material forming the package is not limited to a base material including an aluminum foil layer or a transparent resin layer having strong specular reflection light, and may be a base material including a paper layer.

The polarization directions of the first polarizing filter and the second polarizing filter are adjusted according to the material of the package, the positional relationship between the package and the irradiation means, and the like so that the heat-sealed portion can be clearly imaged. Specifically, in order to reduce the influence of the specularly reflected light, the crossing angle of the polarization directions should be close to 90 degrees, and to brighten the image, it should be close to 0 degrees. Needless to say, when the first polarizing filter and the second polarizing filter are orthogonal to each other, the reflected light from the heat seal portion is completely blocked.

As a result, it is possible to obtain a clear image that does not have white jumps due to loss of brightness gradation information due to specular reflection light, and black crushing due to loss of brightness gradation information due to shadows. It has an advantageous effect that the height can be increased. Further, the number of light sources included in the irradiation means is not limited. By irradiating light with uniform polarization angles from multiple directions with multiple light sources to prevent shadows from appearing in the captured image as in the case of a surgical light, the heat-sealed part can be captured more clearly. ..

The striped determination pattern acquisition unit, which is a determination unit, acquires a bright and dark striped periodic pattern consisting only of brightness from the image of the lattice points. In the image of the lattice points, the convex portions of the lattice points that easily reflect light appear bright, and the streak-shaped concave portions arranged between the lattice points appear dark (see FIG. 9D). Based on this difference in lightness, the line connecting the convex portions of one row arranged in one direction in the array of the grid points in the two directions is converted into one bright stripe, and along the line connecting the convex portions. The streak-like depressions are converted into a single dark stripe, and a light-dark striped periodic pattern consisting only of brightness is acquired. Specifically, a well-known Fourier transform, Gabor filter, moire process, etc. may be combined to obtain a bright and dark striped periodic pattern consisting of only brightness.

When there is no defect in the heat seal portion, a bright and dark striped periodic pattern in which bright stripes and dark stripes periodically appear is acquired according to the periodic arrangement of lattice points (see FIG. 9F). .. On the other hand, when a defect such as biting of powder particles occurs in the heat seal part, the heat seal part bulges in a convex shape, so an image in which a convex part deviated from the periodic array of lattice points is reflected Is obtained. When a bright and dark striped periodic pattern is acquired from an image of a defective grid point, the width of the bright and dark stripes is partially thickened or narrowed, and a portion deviating from the cycle of the bright and dark stripes is formed (Fig. 9 ( C) See figure).

Defect determination means forming the determination means, the bright portion or dark portion deviated from the cycle of the stripe, and the light and dark striped periodic pattern obtained from the non-defective product is compared and determined, and the width of the bright portion or the dark portion deviated from the cycle, When it is out of the predetermined threshold width, it is determined that the heat seal portion has a defect. By acquiring the striped periodic pattern based on the arrangement of the lattice points, even a minute defect having the same size as the lattice points can be detected with high accuracy. In addition, since a striped periodic pattern that does not include a hue and is composed of only brightness is inspected, there is an advantageous effect that the amount of information is small and the inspection time can be reduced.

Here, the predetermined threshold width is based on the width of the bright portion or the dark portion of the light-dark striped periodic pattern extracted from the non-defective product, and a minute defect permitted by the product standard is arbitrarily determined to be a non-defective product. The threshold width that can be set in. For example, in the case of a powdered medicine that a person eats, it is preferable to set the threshold width narrow so that a defect can be detected with higher accuracy. On the other hand, in the case of a granular material used for paint or the like, the threshold width may be set wide so that the yield can be increased.

According to the first aspect of the present invention, it is possible to obtain a clear image without blown-out whites in which gradation information of brightness due to specular reflection light is lost, and black shadows in which gradation information of brightness due to shadows is lost. Therefore, there is an advantageous effect that the accuracy of the defect inspection can be increased. Further, even a minute defect having the same size as a grid point can be detected with high accuracy, and a striped periodic pattern made up of only lightness without hue is inspected. Therefore, there is an advantageous effect that the inspection time can be shortened.

A second invention of the present invention is the inspection means of the first invention, characterized in that the polarization directions of the first polarizing filter and the second polarizing filter are aligned. Thereby, the image of the grid point can be acquired in a bright and clear state, and the defect can be inspected with high accuracy.

A third invention of the present invention is the inspection means according to the first or second invention, characterized in that the image of the grid point is acquired by one-time imaging. Since the image of the lattice point is captured by the two polarization filters in the state of less specular reflection, the image with less specular reflection can be acquired even with one image capturing. Then, the determination means only needs to perform the determination process for one image. This makes it possible to inspect for defects in a short time.

A fourth invention of the present invention is the inspection means of the first to third inventions, wherein the striped image acquisition means creates a striped periodic pattern of hue and lightness from the image of the grid points. From the above, a bright and dark striped periodic pattern consisting only of the brightness is acquired.

Since the striped periodic pattern of hue and lightness is once created, when the striped periodic pattern consisting of only light and dark is acquired, it is possible to apply correction in advance according to the hue. By correcting the hue difference, even if the hue of the heat-sealed portion is partially different due to printing or the like, it is possible to obtain a light-dark striped periodic pattern having only accurate lightness. Thereby, even if the hue of the heat-sealed portion is partially different due to printing or the like, erroneous detection is unlikely to occur, and the defect can be inspected with high accuracy.

5th invention of this invention is an inspection means of 1st-4th invention, Comprising: The said striped determination pattern acquisition means WHEREIN: At least any one direction of the 2 directions which the said grid point intersects. The feature is that a bright and dark striped periodic pattern consisting of only brightness is acquired.

If the obtained striped periodic pattern is only in one direction, the amount of information to be inspected is small, and the inspection can be performed faster. If the acquired striped periodic pattern is bidirectional, the inspection can be performed with higher accuracy. Further, in the case of the packaging sheet, a striped periodic pattern extending in different directions may be acquired depending on the position of the heat seal portion. Thereby, even with one inspection means, there is an advantageous effect that the inspection can be performed quickly or with high accuracy depending on the form of the package.

A sixth invention of the present invention is the inspection means of the first to fifth inventions, wherein the inspection means includes an inter-axis angle adjusting means between an optical axis and a photographing axis, and the optical axis is the irradiation. A virtual axis connecting the means and the package, the photographing axis is a virtual axis connecting the photographing means and the heat seal portion, and the inter-axis angle adjusting means is the optical axis and the photographing axis. It is characterized in that the angle between the axes can be adjusted so that the specular reflection of the image can be reduced.

The angle between the optical axis and the photographing axis may be adjusted by changing the mounting angle of the light source forming the irradiation means and changing the angle of the optical axis. In addition, the distance between the irradiation unit and the package or the distance between the package and the photographing unit may be changed to adjust the axial distance. As a result, even if the material of the package, the size of the heat-sealed part, etc. differ depending on the production line, it is possible to reduce specular reflection from the captured image with a single inspection means, and it is possible to reduce defects with high accuracy. Can be inspected.

A seventh invention of the present invention is the inspection means of the first to sixth inventions, characterized in that it is provided with a threshold width setting means for setting the threshold width. As a result, it is possible to determine that a minute defect permitted by the product standard is included in a non-defective product, and the yield is not excessively reduced.

According to the first aspect of the present invention, it is possible to obtain a clear image that does not have white spots where brightness gradation information due to specular reflection light is lost, and black crushing where brightness gradation information due to shadows is lost. It is possible to obtain the advantageous effect that the accuracy of the defect inspection can be increased. Further, even a minute defect having the same size as the grid point can be detected with high accuracy, and the inspection time can be shortened.
-According to the second aspect of the present invention, it is possible to acquire an image of a grid point in a bright and clear state and inspect a defect with high accuracy.
-According to the third aspect of the present invention, a defect can be inspected in a short time.

-According to the fourth aspect of the present invention, even if the hue of the heat seal portion is partially different due to printing or the like, erroneous detection is unlikely to occur and a defect can be detected with high accuracy.
-According to the fifth aspect of the present invention, even with one inspection means, there is an advantageous effect that it can be inspected quickly or with high accuracy depending on the form of the package. Play.
According to the sixth aspect of the present invention, even if the material of the packaging body, the size of the heat-sealed portion, etc. differ depending on the production line, one inspection means reduces the specular reflection from the captured image. Therefore, the defect can be inspected with high accuracy.
-According to the seventh aspect of the present invention, it is possible to determine that a minute defect permitted by the product standard is included in a non-defective product, and the yield is not excessively reduced.

Explanatory drawing explaining the structure of an inspection means (Example 1). Explanatory drawing of the image of a heat seal part (Example 1). Explanatory drawing of the image of a heat seal part (Example 2). Explanatory drawing of the image of a heat seal part (Example 3). The block diagram of an inspection means (Example 3). Explanatory drawing of an inter-axis angle adjusting means (Example 4). Explanatory drawing of an inter-axis angle adjusting means (Example 5). Explanatory drawing (reference figure) explaining the defect of a heat-sealing part. The photograph explaining the defect of the heat seal part (reference figure).

The inspection means for determining the defect of the heat seal part is equipped with two polarizing filters so that the image of the lattice points reflected by the heat seal part can be acquired in a state with less specular reflection. From an image with less specular reflection, a bright and dark striped periodic pattern consisting only of lightness is obtained from the image of the lattice points, and the bright or dark part of the striped periodic pattern is out of a predetermined threshold width. The seal portion is determined to be defective. In the following examples, the packaging body is described as an example of a packaging sheet of a powdered medicine.

In the first embodiment, the configuration of the inspection unit 1 and the bright and dark striped periodic pattern obtained when the defective portion is inspected early will be described with reference to FIGS. 1, 2 and 9. FIG. 1 shows the structure of the inspection means. FIG. 1A shows a side view of the inspection means. FIG. 1B shows a view of the irradiation unit and the image pickup unit as seen from below. FIG. 1C shows an explanatory view for explaining the positional relationship between the irradiation means and the packaging sheet. In FIG. 1A, the light irradiation range is shown by a broken line, and the imaginary line of the defective product discharge conveyor at the time of defective product discharge is shown by a broken line. In FIG. 1(B) and FIG. 1(C), the polarization direction of the first polarization filter is indicated by diagonal lines, and the second polarization filter is colored.

FIG. 2 shows a process in which the determination unit acquires a light-dark striped periodic pattern composed only of lightness from an image of lattice points forming a heat seal. FIG. 2(A) shows an image of the heat-sealed portion in which dust is caught. FIG. 2B shows a striped periodic pattern of hue and brightness created from the image of the heat-sealed portion. FIG. 2C shows a light and dark striped periodic pattern consisting of only the lightness acquired from the striped periodic pattern of hue and lightness. FIG. 9 is a photograph showing a process of obtaining a bright and dark striped periodic pattern. 9A to 9C show the case of defective products, and FIGS. 9D to 9F show the case of non-defective products.

The inspection means 1 is provided in the production line for the packaging sheet 100 between the heat sealing device for the packaging sheet on the upstream side and the packaging machine on the downstream side. Defective products are inspected while the inspection conveyor 302, which is arranged between the upstream transfer conveyor 300 that sends out the heat-sealed products and the downstream defective product discharge conveyor 301, transfers the packaging sheet 100. Done. When it is determined that there is a defective product, the defective product discharge conveyor 301 on the downstream side is inclined downward to discharge the defective product from the manufacturing line (see the imaginary line in FIG. 1A).

The inspecting means 1 includes an irradiating means 10 for irradiating the heat-sealing portion 101 (see FIG. 1C) of the packaging sheet 100 with light, a photographing means 20 for photographing the heat-sealing portion, and a photographing means for photographing. The determination unit 30 determines the state of the heat-sealed portion from the image. Further, the manufacturing line is provided with defective product discharging means 40 for operating the defective product discharging conveyor based on the judgment result of the judging means.

The irradiation means 10 is an annular illumination having a through hole 11 (see FIG. 1B) in the center, and five LED illuminations 12 are annularly arranged at equal intervals on the lower surface. Each of the LED illuminations 12 includes a first polarization filter 13 whose polarization direction is aligned, and irradiates light with a wavelength in one direction from a plurality of directions so that the packaging sheet does not have a shadow (FIG. 1). (See (C) figure). The light quantity of each LED illumination 12 may be adjusted according to the aspect of specular reflection that differs depending on the material, hue, etc. of the package. It goes without saying that the number and arrangement of the LED lights are examples and are not limited.

The image capturing unit 20 includes a camera 21 (see FIG. 1A) for capturing an image of the heat-sealed portion and a second polarization filter 22 (see FIG. 1B). A polarizing filter 22 is attached. The polarization direction of the second polarizing filter 22 is adjusted so that it is not orthogonal to the first polarizing filter 13 and the specular reflection from the package is small.

Specifically, if the crossing angle between the polarization direction of the first polarization filter 13 and the polarization direction of the second polarization filter 22 is close to 90 degrees, specular reflection light is reduced, and diffuse reflection is caused on the surface of the packaging sheet. An image mainly composed of the emitted light is acquired. On the other hand, if the intersection angles are made closer to each other, a brighter image is acquired. The second polarization filter 22 may be, for example, an ND filter (Neutral Density Filter) that can increase or decrease only the amount of light without changing the hue.

The camera 21, which is a photographing means, is arranged so that the packaging sheet can be photographed through the through hole 11 (see FIG. 1B). The photographing unit 20 photographs once when the packaging sheet 100 is conveyed to the inspection conveyor 302 and passes under the camera 21, and an image of a lattice point forming the heat seal 101 (FIG. 2A). See). Since the image is taken with a small amount of specular reflection by the two polarizing filters, it is possible to obtain a clear image with a small amount of specular reflection without combining a plurality of images.

The photographed image acquired by the photographing means 20 is communicated to the determination means 30 by the communication means 23. The communication means 23 is not limited as long as it is a known communication means. The result determined by the determination unit 30 is communicated to the defective product discharging unit 40 by the communication unit 31. The determination unit 30 only needs to inspect a defect from an image obtained by one shot, does not require image combining processing for removing specular reflection, and can inspect a defective portion in a short time with high accuracy. .. When the defective product discharge means 40 acquires the defect determination information of the packaging sheet, the defective product discharge means 40 operates to incline the defective product discharge conveyor 301 (see FIG. 1A) to discharge the defective product. ..

Next, the configuration of the determination means for determining the state of the heat seal portion and the defect of the heat seal portion will be described in detail with reference to FIG. The determination unit 30 includes a striped determination pattern acquisition unit 32 (see FIG. 5) that acquires a light and dark striped periodic pattern consisting of only brightness from the image of the grid points of the heat seal, and heat seals from the light and dark striped periodic pattern. A defect determination unit 33 (see FIG. 5) for determining a defect of a part is provided.

The packaging sheet 100 is manufactured by alternately performing a powder drug filling step and a heat sealing step of welding the boundary edges of adjacent packaging sheets. In the heat-sealing step, the packaging sheet is heat-sealed by a heating sealer, an ultrasonic sealer, or the like so as to form the grid points 102 where the heat-sealing is arranged. The grid points 102 arranged side by side are heat-sealed so as to be aligned with the extending direction of the edge portion 103 of the packaging sheet (see FIG. 2A).

The powder bite 105 is generated when heat sealing is performed in the heat sealing step in a state where the powdered medicine is sandwiched between the boundary edges 104 of the packaging sheet (see FIG. 2A). The size of the defective portion due to powder biting differs depending on the particle size of the powder or granular material. In the first embodiment, the processing of the determination means will be described by taking as an example a case in which the size is the same as that of one convex portion 106 forming the aligned grid points.

Convex portions 106 are periodically arranged in the grid points 102 arranged side by side, and since the convex portions easily reflect light, they are reflected brightly in the captured image (FIG. 2A and FIG. 9D). ) See figure). On the other hand, the streak-shaped concave portion 107 between the adjacent convex portions is darkly reflected in the captured image because it is difficult to reflect light. The dust bites 105 appear as protrusions at positions different from the periodic arrangement of the grid points 102 arranged side by side (see FIGS. 2A and 9A).

The striped determination pattern acquisition means creates the striped periodic pattern 110 (see FIG. 2B) of the hue and lightness of the image of the aligned grid points 102 by a known Fourier transform, Gabor filter, or the like. By the moire process, the bright and dark striped periodic pattern 120 (see FIG. 2C) composed of only the brightness is acquired. When only the vertical component is extracted by Fourier transform from the image of the grid point 102 (see FIGS. 2A and 9D), the direction along the boundary edge 104 (hereinafter referred to as the vertical direction) is obtained. The convex portions 106 arranged at equal intervals (see FIG. 2A) are extracted so as to form a line connecting the convex portions in the vertical direction, and are converted into bright stripes 111 including hue and lightness (FIG. 2). 2(B) and FIG. 9(E)). More specifically, in the bright stripe 111, the convex portion 106 has a thick width and the portion between the adjacent convex portions has a narrow width, and is converted into a wavy stripe as a whole.

The concave portion 107 along the line connecting the convex portions 106 is converted into a dark stripe 112 including hue and lightness. The periodic array of grid points 102 is converted into bright stripes 111 and dark stripes 112 containing hue and lightness, and a striped periodic pattern 110 of hue and lightness is created (FIG. 2B, FIG. 9( E) See figure). When there is a hue difference in the heat-sealed portion due to printing on the surface of the package, the hue difference is corrected so that the hue does not affect the lightness. For example, if it is yellow, it becomes a bright portion even if it is a monochrome image, and if it is blue, it becomes a dark portion. To eliminate this difference, correction may be made to increase the brightness of blue. If the packaging material and hue do not affect the acquisition of the bright and dark striped periodic pattern without correcting the hue difference, the hue correction is not necessary.

The portion of the dust particles 105 is a protrusion different from the periodic array of the lattice points 102, and the periphery of the protrusion appears in the image as either a bright portion or a dark portion. In the dust-entrapped portion 113 that appears as a bright portion, the bright stripes 111 have a wide width that is partially deviated from the cycle and protruded to the side by Fourier transform (FIGS. 2B and 9B). )), and the dust-entrapped portion 114, which appears as a dark portion, has a narrow width so that the dark stripes 112 are partially out of the cycle.

Then, when the striped periodic pattern 110 of hue and lightness is subjected to moire processing to extract the lightness, in the non-defective portion, a bright and dark striped pattern in which substantially straight light stripes 121 and dark stripes 122 are periodically repeated. The periodic pattern 120 is acquired (see FIG. 9F). On the other hand, in the powder biting portion, the bright portion 123 having a striped periodic pattern is projected laterally and the dark portion 124 becomes thin (see FIGS. 2C and 9C).

The defect determining means determines that the heat seal part has a defect when the bright part 123 or the dark part 124 of the striped periodic pattern is out of the predetermined threshold width. The predetermined threshold width may be determined on the basis of the width of the striped periodic pattern (see FIG. 9F) obtained from non-defective products and the size of the defective portion allowed by the product standard. For example, if the bright portion 123 or the dark portion 124 is projected so as to exceed the majority of the pitches of the lattice points, it may be determined as defective. In addition, compared with the width of the striped periodic pattern of only light and dark acquired from the non-defective product, the light portion or dark portion exceeds the width of N pixels (N is an arbitrary integer set) on the captured image. It may be determined to be defective if it is coming out. The value of N may be set according to the type of package.

In the second embodiment, a bright and dark striped periodic pattern obtained when a defective portion is inspected with higher accuracy will be described with reference to FIG. FIG. 3A shows a partially enlarged view of the heat seal portion 101. FIG. 3B shows a case where a striped periodic pattern 130 of hue and lightness in the vertical direction is acquired, and FIG. 3C shows a striped periodic pattern 140 of hue and lightness in the horizontal direction. Is shown.

The defective portion 108 is smaller than the size of one convex portion 106 forming a lattice point, and is generated at a position between the convex portions 106 which are arranged in the vertical direction (FIG. 3A). See figure). When a striped periodic pattern 130 of hue and lightness in the vertical direction is created from this image in the same manner as in Example 1, the width of the defective portion in the horizontal direction is smaller than the width of the thick portion 131 of the bright portion, and the defective portion is defective. The portion 108 does not protrude from the striped periodic pattern (see FIG. 3B).

On the other hand, when the striped periodic pattern 140 of hue and lightness in the horizontal direction is created, the defective portion is located between the convex portions and the convex portions that form the column. In the meantime, a bright portion 142 is formed outside the periodic arrangement of the lattice points (see FIG. 3C). In this way, if a striped periodic pattern in two directions is created from one captured image, even a microscopic defect can be inspected with high accuracy.

In the third embodiment, the inspection unit 2 that divides the image of the heat-sealed portion into a plurality of areas and acquires a bright and dark striped periodic pattern extending in different directions for each area will be described with reference to FIGS. 4 and 5. To do. In addition, a block diagram of the inspection means will be described with reference to FIG. FIG. 4A shows a state in which the heat seal portion is divided into a plurality of areas. FIG. 4B shows a partially enlarged view of a portion surrounded by a broken line in FIG. 4A. FIG. 5 is a block diagram illustrating the configuration of the inspection unit 2.

The area determination unit 50 (see FIG. 5) has an area 51 for acquiring a striped periodic pattern extending in the horizontal direction so as to divide the heat-sealing portion 101 extending in the two intersecting directions into a plurality of areas, and a vertical direction. It is determined which one of the regions 52 for which the striped periodic pattern extending to the region belongs to belongs (see FIG. 4A). Here, in order to reduce the number of stripes to be compared with non-defective products, it is possible to acquire a striped periodic pattern extending long from the grid point. Specifically, the area determination unit 50 determines that the edge portions 103 on both sides of the packaging sheet are the areas 51 in which the lateral periodic striped pattern is acquired (see FIG. 4B), and the adjacent portions are determined. The boundary edge portion 104 of the packaging sheet is determined as the area 52 where the vertical striped periodic pattern is acquired. The acquisition of the striped periodic pattern is similar to that in the first embodiment.

Next, the structure of the inspection means 2 will be described with reference to FIG. The inspection unit 2 includes a control unit 60 including an image capturing unit 20 and a determination unit 30. The control unit 60 includes a determination unit 30 including a striped determination pattern acquisition unit and a defect determination unit, the area determination unit 50 described above, and a threshold width setting unit 61 for setting a threshold width for defect determination. include.

The control means 60 is provided with an input means 70 for inputting a calculation formula necessary for obtaining the striped periodic pattern, a threshold width allowed by a product standard, area information necessary for area determination, and the like, and the input means. The storage means 71 for storing the stored information is connected. In addition, the inspection unit 2 includes a selection unit 72 for selecting information stored in the storage unit, a display unit 73 for displaying the information, and a defective product discharge unit 40 for discharging defective products based on the inspection result. It is connected.

The control unit 60 reads out the information stored in the storage unit 71 based on the information selected by the selection unit 72, determines the processing content of the determination unit 30, and sets the threshold width by the threshold width setting unit 61. .. When the area determination is not performed, when the imaged image is captured by the image capturing unit 20, the striped determination pattern acquisition unit 32 acquires a bright and dark striped periodic pattern, and the defect determination unit 33 determines whether there is a defect. Let me judge. When the area determination is performed, the area determination means 50 determines the area of the heat seal, and then the failure determination is performed. If the defective product is determined to be defective, the defective discharge unit 40 transmits a discharge signal to the defective product discharge conveyor (see FIG. 1A) to remove the defective product from the manufacturing line.

In the fourth embodiment, an inspection means 3 including an inter-axis angle adjusting means 80 between an optical axis connecting the irradiation means and the packaging body and an imaging axis connecting the photographing means and the packaging body will be described with reference to FIG. In FIG. 6, the optical axis and the photographing axis are indicated by the alternate long and short dash line, and the directions in which the irradiation means and the photographing means are moved are indicated by the arrows. FIG. 6(A) shows the state before adjusting the inter-axis angle, and FIG. 6(B) shows the state after adjusting the inter-axis angle.

The inter-axis angle adjusting means 80 changes the distance between the irradiation means 10 or the photographing means 20 and the packaging body to change the inter-axis angles 81 and 82 formed by the optical axis 14 and the photographing axis 24. Here, the adjustment of the inter-axis angle will be described based on the packaging body 83 having a large area. The distance between the photographing means 20 and the packaging body is increased, and the height is adjusted so that the photographing range is widened (FIG. 6A). The irradiation unit 10 adjusts the angle of the optical axis 14 and the height position distance according to the distance so that specular reflection is reduced.

When a small package 84 having different product specifications is produced, the distance between the photographing means 20 and the package is changed to a shorter distance, and the height of the heat-sealed portion is adjusted so that the resolution of the heat-sealed portion is further increased. (FIG. 6(B) figure). Next, the inter-axis angle adjusting means 80 adjusts the height position of the irradiating means 10 in accordance with the changed separation distance so that specular reflection is reduced. That is, the inter-axis angles 81 and 82 between the optical axis 14 and the photographing axis 24 are adjusted to reduce the specular reflection (see FIGS. 6A and 6B).

In the fifth embodiment, the inspection means 4 including the irradiation means extending in the axial direction and including the second inter-axis angle adjusting means 90 will be described with reference to FIG. 7. FIG. 7A shows a plan view of the inspection means. FIG. 7(B) shows a front view of the inspection means viewed from the downstream side in the transport direction before adjusting the inter-axis angle. FIG. 7C is a front view of the inspection means viewed from the downstream side in the transport direction after adjusting the inter-axis angle. In FIG. 7, the optical axis and the photographing axis are indicated by alternate long and short dash lines, the direction in which the angle of the irradiation means is changed is indicated by an arrow, and the conveying direction of the inspection conveyor is indicated by a thick arrow.

The irradiation means 15 is a pair of axial illuminations provided with the first polarization filter 13, and the conveyance direction of the inspection conveyor 302 (Fig. 7(A) (see the thick arrow in FIG. 7A). The irradiating means 15 is axially movable around a rotating shaft 16 so that the angle of the light emitted toward the package can be adjusted. Further, the axial illumination can be easily installed even in a narrow place, and the inspection means can be easily installed even in a production line where the installation place is limited. It is needless to say that the irradiation unit 15 may be disposed on the upstream side and the downstream side of the photographing position so as to extend in the direction intersecting the transport direction.

The second inter-axis angle adjusting means 90 adjusts the inter-axis angles 91 and 92 formed by the optical axis 14 and the photographing axis 24 by changing the angle of the optical axis 14 connecting the irradiation means 15 and the packaging sheet 100. Let Specifically, the angle of the optical axis 14 is adjusted by rotating the rotating shaft 16. (See FIGS. 7B and 7C). Even if the packages have the same size, if the materials of the base materials are different, the state of specular reflection is also different. The inter-axis angle may be adjusted in advance so as to reduce the specular reflection depending on the package, and the image is captured.

(Other)
In the present embodiment, the case where the lattice points are arranged in parallel with the four sides of the packaging sheet has been described, but the arrangement of the lattice points is not limited to this. For example, even when the lattice points are arranged diagonally or concentrically, the striped periodic pattern may be acquired accordingly and the defect may be determined as in the present embodiment.
The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The technical scope of the present invention is not limited to the above description, but is defined by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1, 2, 3, 4... Inspection means, 100, 200... Packaging sheet,
10... Irradiation means, 20... Imaging means, 30... Judgment means,
11... Through hole, 12... LED illumination, 13... First polarization filter, 14... Optical axis,
15... Irradiation means, 16... Rotating shaft,
21... Camera, 22... Second polarization filter, 23... Communication means, 24... Shooting axis,
31... Communication means, 32... Stripe judgment pattern acquisition means, 33... Defective product judgment means,
40... Defective product discharging means, 50... Area determining means, 51, 52... Area,
60... Control means, 61... Threshold setting means,
70... Input Means, 71... Storage Means, 72... Selection Means, 73... Display Unit,
80... Inter-axis angle adjusting means, 81, 82... Inter-axis angle, 83, 84... Package,
90... Second inter-axis angle adjusting means, 91, 92... Inter-axis angle,
101... Heat seal part, 102... Lattice point, 103... Edge part, 104... Border edge part,
105... powder biting, 106... convex portion, 107... concave portion, 108... defective portion,
110... a striped periodic pattern of hue and lightness, 111... bright stripes, 112... dark stripes,
113... the dust-encapsulated portion that appears as the light portion, 114... the dust-entrapped portion that appears as the dark portion,
120... bright and dark striped periodic pattern, 121... bright stripes, 122... dark stripes,
123... bright part, 124... dark part,
130... a striped periodic pattern of hue and lightness in the vertical direction, 131... a thick portion of a light portion,
140... a striped periodic pattern of lateral hue and lightness, 141... bright stripes, 142... bright part,
300... Conveyor, 301... Defective product discharge conveyor, 302... Inspection conveyor

Claims (7)

A peripheral part is packaged by heat-sealing, which is a means for inspecting a heat-sealing part of a package in which the heat-sealing forms a grid point.
Irradiating means for irradiating the heat seal portion with light, photographing means for photographing the heat seal portion, and judging means for judging the state of the heat seal portion,
The irradiating means irradiates the heat seal part with light having a wavelength in one direction that has passed through the first polarizing filter,
The photographing means passes an image through the second polarizing filter to obtain an image,
The polarization directions of the first polarization filter and the second polarization filter are not orthogonal to each other, and the image of the lattice point reflected by the heat seal unit is acquired in a state of little specular reflection,
The determination means includes a striped determination pattern acquisition means and a defect determination means,
The striped determination pattern acquisition means acquires a bright and dark striped periodic pattern consisting of only brightness from the image of the grid points,
The defect determination means, when the bright or dark part of the striped periodic pattern is out of a predetermined threshold width, determines that the heat seal part is defective,
Inspection means characterized in that. The polarization directions of the first polarizing filter and the second polarizing filter are aligned,
The inspection means according to claim 1, wherein: The image of the lattice points is acquired by one shot,
The inspection means according to claim 1 or 2, characterized in that. The striped image acquisition means creates a striped periodic pattern of hue and lightness from the image of the lattice points, and then obtains a light and dark striped periodic pattern consisting of only the lightness,
The inspection means according to any one of claims 1 to 3, wherein: The striped determination pattern acquisition means acquires a striped periodic pattern of light and dark consisting of only the lightness in at least one of two directions in which the grid points intersect,
The inspection means according to any one of claims 1 to 4, characterized in that: The inspecting means includes means for adjusting an inter-axis angle between the optical axis and the photographing axis,
The optical axis is a virtual axis connecting the irradiation means and the packaging body,
The photographing axis is a virtual axis connecting the photographing means and the heat seal portion,
The inter-axis angle adjusting means allows the inter-axis angle between the optical axis and the photographing axis to be adjusted, and specular reflection of the image can be reduced.
The inspection means according to any one of claims 1 to 5, wherein: The inspection means includes a threshold width setting means for setting the threshold width.
The inspection means according to any one of claims 1 to 6, wherein:

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