JP2001041900A - Sheet package inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply detect all of important flaws including the flaw in a pocket part with high probability by using a color. SOLUTION: When a reflecting plate 17 is arranged under a packaging sheet 16 to irradiate the packaging sheet with light from above, a light source is arranged at a position shifted from the line of sight of a camera 11 between the camera 11 and the packaging sheet 16 and the mirror surface reflected image component from the packaging sheet 16 is reduced. A color code distribution image is calculated from a reflected image, a transmitted image or the color distribution of both images or the density distribution of a single or a plurality of colors to obtain a single or a plurality of the variable density distribution images of the reflected or transmitted image and the inspection of the shape or color of a part or sheet packaged with a sheet and the detection of the flaw such as foreign matter or a stain thereof are performed from the color code distribution image or variable density distribution image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet packaging inspection apparatus for detecting foreign matter, damage and dirt generated during a tablet sheet packaging process in a non-contact manner by visual inspection, and in particular, to both reflected light and transmitted light. Observation with a TV camera using
The present invention relates to an inspection device for inspecting.

[0002]

2. Description of the Related Art In this specification, the term "tablet inspection" refers to inspection of tablets and packaging sheets and inspection for defects such as foreign substances mixed in a space where tablets are placed, so-called pockets, unless otherwise specified. Will be used as a generic term including Unless otherwise specified, the term "sheet packaging inspection" is used as a general term including inspection of parts to be packaged and packaging sheets and inspection of defects such as foreign substances mixed in a space where parts called so-called pockets are placed. It shall be. Unless otherwise specified, the entire inspection target including the tablet and other parts and the sheet part that wraps it is simply referred to as a “packaging sheet”, and the sheet part consisting of only the sheet is used.
To be distinguished.

Hereinafter, a conventional tablet inspection which is important as one of inspections of a sheet package will be described. The inspection area in the tablet inspection is roughly divided into a tablet portion, a packaging sheet portion, and a portion commonly called a pocket for placing and securing the tablet. As inspection items, tablet shape, tablet shape,
Character symbols, cracks, cracks, folds, chips, dirt, stains, and deposits on the tablet surface. Further, the packaging sheet and the pocket portion include spots, dirt, foreign matter which is easily generated in the packaging process, tablet fragments, hair and fibers, and the like. In addition, foreign tablets may be mixed. On the other hand, as the inspection method, conventionally, a method called a reflection type and a method called a transmission type have been separately considered. The reflection type is a method of irradiating light from above the packaging sheet and detecting the defect by observing with a television camera placed above. This is a method for detecting defects by observing transmitted light with a television camera. In the reflection type inspection, it is possible to inspect the tablet shape, foreign substances on the tablet portion, and foreign substances mixed in the sheet. On the other hand, the transmission type is used for detecting a foreign substance mixed in a sheet and detecting a tablet shape.

[0004]

As described above, conventionally, two types of tablet inspection methods, a reflection type and a transmission type, have been considered. However, these methods have the following important problems. First, in the reflection method, highlights are often observed in pocket portions due to multiple reflection and specular reflection of light and a concave reflecting mirror effect, and the highlights are false defects. For this reason, the pocket portion is detected in advance, and the corresponding area on the image is logically masked and excluded from the inspection target. Therefore, the detection of the pocket part becomes complicated and the inability to inspect the pocket part is a serious problem. There is also a considerable specular reflection component on the sheet surface, which may appear as a highlight. Highlights appearing in such pockets and seats can cause serious false defects,
Conventionally, there is no method for identifying and removing only the false defect. Next, regarding the transmission method, an elongated foreign substance such as hair has a very low contrast in a transmission image due to a diffraction phenomenon or the like, which causes a serious omission of defect detection. Further, it is not possible to make an important distinction as to whether the defect mixed in the sheet is a tablet fragment generated due to tablet damage or a foreign substance due to dust. As described above, it is not possible to stably identify and detect all important defects including all defects in both the reflection type inspection and the transmission type inspection. Furthermore, it is impossible at all to detect all defects with high probability in all regions simply by combining both methods. Therefore, an object of the present invention is to solve these conventional problems and to provide a sheet packaging inspection device capable of easily detecting all important defects including defects in the pocket portion with a high probability and easily. It is in.

[0005]

In order to achieve the above object, a sheet packaging inspection apparatus according to the present invention comprises a light source and a two-dimensional sensor above a packaging sheet, and means for inputting a reflection image from above the packaging sheet. Means for inputting a transmission image of the packaging sheet below the packaging sheet, and binarizing or multi-leveling the reflection image and the transmission image to form a plurality of binary or multi-valued images. Then, a code distribution image representing the density distribution of the plurality of images is generated, and thereafter, from the code distribution, defects such as contaminants, damage, and dirt in parts, packaging sheets, and pockets are detected. Also disclosed is a method of performing a logical operation between images instead of adding a code and identifying a defect from the result. Further, region division is performed based on the density distribution of the input image or the code distribution, and thereafter, the code value of each divided region is added to the code value of the peripheral region of the region as an auxiliary code, Detect defects. Further, in order to avoid omission of defect detection, a half mirror or a reflector having a reflection component of at least 5% or more is provided immediately below the packaging sheet. On the other hand, in order to enhance the inspection efficiency, the lighting means simultaneously equipped with light sources having different color distribution emission characteristics above and below the packaging sheet, or the light sources are simultaneously arranged above and below the packaging sheet, and each of the light sources An illuminating means having a color filter having a different color distribution is arranged between the wrapping sheet and a two-dimensional sensor is arranged above the wrapping sheet, and thereafter, two directions above and below the wrapping sheet. A two-dimensional image is input while the light source is turned on, and in the input image, the reflected image component is made to correspond to the color distribution of the illumination light from above the packaging sheet, and the transmitted image component is the color of the illumination light from below. Means are provided for separating the reflected image and the transmitted image from the input image by making them correspond to the distribution. Further, a color filter containing components common to the transmission wavelength components is provided above and below the packaging sheet, and the common wavelength components of the illumination light from above and below are removed from the input image. And the transmitted image component. In addition, as a new method of detecting defects without separating the reflected image component and the transmitted image component, a dimming device is used to adjust the ratio of the amount of reflected light and the amount of transmitted light, input an image, and perform multi-value processing. Detect defects.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. 2 and 3 are a plan structural view and a side sectional view of a packaged tablet to be tested according to the present invention. Generally, a packaged tablet contains several tablets of several mm.
The tablets are arranged at intervals of 10 to several mm, but one tablet T is shown in FIG. 2 for simplicity. FIG. 2 is a plan view when the packaged tablet T is viewed from above together with the pocket P. FIG. 3 shows a cross section of the pocket portion, and the tablet T is in a pocket P. In the packaging process, as shown in FIG.
One tablet T is placed in a concave portion of the sheet S called a pocket, and then another sheet S is attached to the upper surface as shown in FIG. This sheet S is also called a seal and is distinguished from the sheet S shown in FIG. 3A, but in this embodiment, both are called sheets and are not particularly distinguished. Also,
The inspection target areas shown in FIGS. 3A and 3B are both called packaging sheets. Fig. 3
This is performed in the states of (a) and (b). The position of the camera may be located either above or below FIG. In the example,
The camera was placed on the upper side, and as for (b), the packaging sheet S was turned upside down as shown in (c). In the inspection method, the position of the camera and the orientation of the packaging sheet S are treated as arbitrary.

FIG. 4 is an explanatory diagram showing types of defects.
Here, a false defect in the pocket portion is also shown. The tablet portion T is white in this embodiment. F
Are highlights caused by multiple reflections of light in the pocket, concave mirror efficiency, and specular reflection on the sheet surface, and particularly appear in pockets with high probability under ordinary lighting. J1 is a chipped portion on the side of the tablet, and J2 is a crack in the tablet. G1 is a white-system defect, which corresponds to a tablet fragment attached to the tablet. These are often impossible to detect visually.
However, if a black edge is observed in the outline of the fragments attached to the tablet, it is detected as a black foreign substance.
G2 is a black contaminant, which corresponds to dust or dirt on the tablet surface. Cracks on the tablet surface and contour patterns of tablet fragments as described above may also be observed as G2.
H1 is a white-based foreign substance, and a tablet fragment is one of the important defects corresponding thereto. H2 is a black-based foreign matter, and is also an important defect. Dirt and mixed dust generated in the packaging process correspond to this. I is an extra-fine linear foreign matter such as extra-fine hair or fiber, and is an important defect that has a high probability of being mixed in the packaging process. This foreign matter has a high risk of being overlooked in the reflection image due to low contrast in the conventional method. In a transmitted image, there is a high possibility that the image is not detected due to a diffraction phenomenon. N is a stain on the sheet portion. Although clear stains can be treated as foreign matter, stains of the same color system as the sheet color may not appear in the transmitted image like defect I. The notation N is expressed separately from dirt that can detect such a defect as a foreign substance.

FIGS. 5 and 6 are diagrams for explaining how bright each defect is observed in an input image in the present invention. FIG. 5 schematically shows an image when the tablet is observed from above. Note that a bright spot on the image is expressed as white, and a dark spot is expressed as black. Tablet T,
Only highlight F and white defect H1 are observed white. G
2 is observed black on a white background. As described above, I and N have a high risk of being overlooked due to a low contrast in a reflection image, and are likely not to be detected in a transmission image due to a diffraction phenomenon or a small transmittance difference. The above countermeasures will be described with reference to FIG. In the present invention, the half mirror M is provided directly below the packaging sheet 1. Part of the light L passing through the sheet portion is reflected by the half mirror M, and returns upward as a reflected light ray R. However, since light does not return at the place where the small defect I exists, the light is darker than the sheet portion, and therefore, the contrast of the defect is increased and the defect can be identified. In FIG. 5, for this reason, I and N are displayed in stronger black. According to the experiment, the reflectance of the half mirror was required to be 5% or more. Also, ground glass having surface reflection may be used as a half mirror in some cases. FIG.
Is a transmission image when illuminated from below the packaging sheet and observed with a camera above. Tablet T, defects H1 and H2 are observed in black. Highlights F, extra-fine hair and fibers I often do not appear in transmission images.

FIG. 1 is a diagram for explaining the principle of detecting a defect from the two image data shown in FIGS.
FIG. 1A shows a defect, and FIG.
When (a) is represented by three types of codes, the codes of each defect are shown, and there are a display method of a 2-bit code, an adjacent code, and a 4-bit code. In the two-bit code display method, the corresponding pixels in FIGS. 5 and 6 are represented by a 2-bit code with white portions being 1 and black portions being 0. The crack in J2 is represented by 01,
The missing portion of J1 is represented by 01. For example, tablet T
Is 1 in a reflection image and 0 in a transmission image, and is 10. Similarly, the defect H2 is 00 because both the reflection image and the transmission image are 0. Similarly, F is 11, J1 and J2 are 0.
1, G1 is 10, G2 is 00, H1 is 10, and I is 01. However, 01 of I and N is the same as 01 of the sheet portion S, but since it can be distinguished from the sheet portion as described above, it is particularly indicated as 0'1.

The presence of a defect is identified from the distribution map of the 2-bit code. However, it is not always possible to determine that J1 and J2 are defects without using the result of performing image processing of identifying the contour of the tablet contour based on the preliminary knowledge about the contour of the tablet. In the embodiment, it was possible to detect the change relatively easily by detecting the positional change in the edge direction. Next, the adjacent code method is an adjacent code distribution diagram in which codes of adjacent areas are described for each area having a relatively small area after area division by labeling processing. However, since J1 has both 10 and 01, it is set to 11. The 4-bit code scheme is a 4-bit code diagram obtained by adding an adjacent code to the code of each pixel. It is clear from this code diagram that it is possible to determine what all the defects fall into. Colors are assigned to each code and the position and type of the defect are displayed in color.
The center of gravity position, area, shape, and type feature amount are calculated and registered in the defect list. As described above, by creating a combination of light and shade information including both a reflection image and a transmission image, that is, a code, it is possible to easily detect the positions and defect classifications of all defects with high accuracy. Thus, in the present invention, a code representing the correlation between the light and dark distribution of both images is formed,
Detect defects from the code. As a result, the detection process is extremely clear and simple, and simple and highly accurate defect detection can be performed.

Further, as another method of this embodiment, instead of generating a code image, a logical operation is performed between each binary or multi-valued image of a reflection image and a transmission image, and the operation result obtained by the operation is obtained. Can be used to detect defects. The outline of the calculation method will be described below. For the reflection image of FIG. 5 and the transmission image of FIG. 6, the reflection image and the transmission image are binarized and subjected to AND processing.
Only the bright F region is extracted for both the reflection image and the transmission image. Also, after inverting the reflection image, AND
When the processing is performed, defects J1 and J2, which are dark areas in the reflection image and bright areas in the transmission image in the resulting image,
I, N and regions P and S are extracted brightly. Area T
Is darker in the result image, so that J1 and J2 can be distinguished. As described above, I and N can be identified by the contrast with S. Also, instead of inverting the reflection image, the transmission image is inverted and an AND process is performed. As a result, the defects G1 and H1, which are bright in the reflection image and dark in the transmission image, and the region T are extracted in the resulting image. Is done. Since G1 exists in the region T, its identification requires multi-value processing. The defect H1 is
Since the regions P and S are dark in this image, they are identifiable.
On the other hand, after inverting both the inverted image and the transparent image, AND
When processing is performed, only the defects G2 and H2 are extracted brightly,
It becomes identifiable. As described above, the defect can be detected by the four AND processes. Note that AN after inverting the image
Defects can also be identified by combining XOR processing, AND processing, and OR processing instead of D processing. For example, XOR and A
J1, J2, G1, and H1 can be identified by a combination of ND processing, and G2 and H2 can be identified by AND and NOT processing. However, since there is essentially no difference from the case of using a combination of inversion and AND, a detailed description is omitted.

FIG. 8 is a code distribution diagram in the case where the quantization of the reflection image and the transmission image is performed at four gradations and three gradations, respectively, instead of the binarization performed in FIG. When the light reflectance of the sheet portion is slightly higher, the reflected light amount of the pocket portion in the reflection image is smaller than that of the sheet portion. Similarly, the defects I and N have a smaller amount of reflected light than the sheet portion. Therefore, the reflection image is changed according to the brightness of the tablet, the pocket, the sheet, and the defect I.
Value. On the other hand, in the transmission image, ternarization is performed according to the light transmittance of the tablet, pocket, and sheet portion. And FIG.
A code in which a plurality of bits of reflection and transmission are created in the same procedure as in (1) is a code attached to a defect, and a code with adjacent codes is a code in parentheses () attached to each defect.
In this way, by making the reflection image and the transmission image multi-valued irrespective of binarization, the position of the defect can be identified in more detail using only the code.

FIG. 9 is a principle diagram of a sheet packaging inspection apparatus showing another embodiment of the present invention, and shows a method of simultaneously taking a reflection image and a transmission image into one image by using a color filter. ing. 1 shows a novel defect detection method of the present invention, in which a light source 3 with a green wavelength band-pass limited color filter 4 and a color camera 2 are placed above a packaging sheet 1 and a red wavelength below the packaging sheet. A light source 5 having a limited color filter 6 having a band pass function is placed, and both light sources 3 and 5 are in a continuous lighting state. A color separation circuit 7 is connected to the color camera 2, and performs green and red color separation from the camera output signal. In this figure, considering that the reflected image component of the camera signal corresponds to the green signal and the transmitted image component corresponds to the red signal, an image is formed from the green signal output from the color separation circuit 7. It can be generated and assigned to a reflection image, and similarly to an image from a red signal, and assigned to a transmission image. 2 separated
After one sheet of image is obtained, the position and classification of the defect are performed by the method of the first embodiment shown in FIG. As described above, since the reflection image and the transmission image can be simultaneously input using the limited color filter, the apparatus is simplified and the inspection time can be reduced by half. It should be noted that eliminating the overlap of the light transmission wavelength regions of the two filters 4 and 6 used at all may increase the cost of the filters and may actually reduce the light transmittance. For this reason, it is desirable to allow overlap.

FIG. 10 is a frequency transmittance characteristic diagram when the light transmission wavelength region of the filter according to the present invention is overlapped. In the transmission wavelength region of the limited color filters 4 and 6, there is a common region. The reflection image component is made to correspond to a signal in a region obtained by removing the common wavelength region from the wavelength region of the illumination for transmission. According to this method, an inexpensive color filter having a high transmittance can be used.

Next, a description will be given of an embodiment of an apparatus and a method for identifying a defect without classifying a reflection image and a transmission image by inputting an image while turning on the illumination on both sides of the packaging sheet. A dimmer is connected to the power supply of each of the two lighting devices placed above and below the packaging sheet. Thus, the ratio of the intensity of the reflection illumination to the intensity of the transmission illumination can be freely selected by adjusting the dimmer. As the light control device, an ND filter and a color filter can be used in addition to the Slidac.
Here, in consideration of the case where the sheet has a color and light absorption and scattering, the amount of light reflected and entering the camera is compared with the amount of light transmitted and entering the camera. The former is simply called the amount of reflected light, and the latter is simply called the amount of transmitted light. First, dimming is performed so that the amount of transmitted light is sufficiently larger than the amount of reflected light. At this time, the density distribution of the observed input image is roughly divided into the following four stages. In order of brightness, level 1 has F, level 2 has J1, J2, I, N,
P and S are classified into levels 3, G1, H1, and T, and the darkest level 4 is classified into G2 and H2.
Therefore, a process of calculating a quaternized image of the input image and classifying it into four levels is performed. Since only F is included in level 1, F can be detected. Since T is not included in level 2, J1 and J2 can be detected. However, for I and N, P and S are included in level 2 and the reflection component is relatively small, so that detection is not possible. Can not. At level 3, since areas S, P, and T are not included, G2 and H2 can be detected. Therefore, this method has a weak point in detecting dirt, thin hair and fibers of the same color on the sheet. Next, when the amount of reflected light and the amount of transmitted light are almost the same, defects detectable in the same manner as described above are F, G2, and H2. Although I and N are within the detectable range for the time being, there is a risk of missing detection. Similarly, when the amount of reflected light is sufficiently larger than the amount of transmitted light, F, G2, H1, and H2 can be detected, and I and N can also be detected.

FIG. 11 is a diagram showing the detection probabilities in the above cases in four stages of 〇, △, △ ′, and ×. The amount of reflected light and the amount of transmitted light are shown as large, medium, and small, and five patterns between them. F, G2, and H2 are relatively detectable without depending on the light amount ratio, but the others greatly depend on the light amount ratio. Therefore, it is necessary to input a plurality of images with different light intensity ratios.
In addition, as shown in FIG. 11, when the amount of transmitted light is slightly increased, J1, J2, and H1 can be detected. Although I and N can be expected to be detectable by dimming, the risk of missing detection is quite high. Therefore, it is clear that a defect can be stably detected by inputting a plurality of images in which the light amount ratio is combined. As described above, a defect can be detected by adjusting the ratio between the amount of reflected light and the amount of transmitted light without separating the reflected image and the transmitted image. Note that this method
This is equivalent to inputting the weighted addition image of the reflection image and the transmission image of the first embodiment, and adjusting the weighting factor by the dimmer at that time. A half mirror or a reflecting mirror corresponding to the ratio between the amount of reflected light and the amount of transmitted light can be used instead of the second light source. In this case, a half mirror or a reflecting mirror may be used while the second light source is kept on. In the latter case, there is an effect that the contrast of the reflection component increases in the detection of the defect I.

In the above embodiment, for the sake of simplicity, the description has been made with reference to FIGS. In addition, a method of separating a reflection image and a transmission image using a color camera has been described. However, in the former case, it is not necessarily limited to a black and white image. That is, the components of the sheet packaging and dirt, foreign substances such as different types of tablets and dust have some color characteristics including black and white, the difference in shading by color, the shading image of a specific color, and the color of the color itself. By using the distribution image, it is possible to separate components and detect defects. This is basically considered to be a part or application of the above-described embodiments, but a specific embodiment that actively uses colors will be disclosed below.

FIG. 12 is a view for explaining an embodiment using colors. However, the structure of the sheet packaging is described in FIG.
The same thing as above shall be used. As shown in FIG. 12A, the color of the sheet S and the pocket P is red R, the color of the tablet T is blue B, the white foreign substances G1 and H1 are white W and the black foreign substance G.
2, H2 is black D. At this time, when a white light source is used as the light source, FIG. 12B shows the color of each portion appearing in the reflection image and the transmission image in (RGB). In the reflection image, crack J2, chipping J1 is (100), highlight F is (111), tablet T is (001), foreign matter G1,
H1 is (111), foreign substances G2 and H2 are (000), fine hair and thread are (000), and dirt is (100), depending on the cause, and sheet S and pocket P are (10).
0). Similarly, in the transmission image, the sheet, pocket, highlight on the sheet, and dirt on the sheet are (1
00) and others are (000). It can also be represented by a 6-bit code which is a combination code of the reflection image and the transmission vortex image.

On the other hand, instead of this color code classification, A
Needless to say, it is also possible to sequentially classify each color by a logical operation such as ND or OR. In the above modification, if a region of only red R is taken out and used as a grayscale image, only the red sheet portion S, pocket P, crack J2, chipped portion J1, and dirt N are extracted. Also, if a region of only red R or blue B is taken out and a grayscale image is formed by inverting the region, foreign matter G1, G2, H1,
Only H2, I and highlight F are extracted. Red R
By taking out a region containing the blue and blue B components and forming an inverted grayscale image, only black defects G2 and H2 are extracted. As described above, by calculating a color code distribution image from a color distribution or extracting an area having one or a plurality of colors, each part can be identified, and it is also possible by a logical operation of the color distribution. .

However, if there are a plurality of regions having the same color, it becomes difficult to separate them. For this reason, the color classification is more finely classified. That is, a method of comparing and classifying hues, a method of comparing differences in color intensities, and a method of comparing and classifying saturation can be considered. Further, the classification based on the density described with reference to FIG. 1 and the color classification as illustrated in FIG. 12 can be used together. As described above, the identification accuracy is significantly improved by using both the color analysis and the density analysis. This combination is included in the words of color analysis and color classification in this specification.
The observed image depends on the color distribution of the light source. FIG.
Assuming that the color of the light source is blue B for the color distribution given in (a), the blue and white foreign substances G1 of the tablet T in the observed image,
H1 is highlighted. Other areas are reduced in color. If the light source is green, the color is reduced except for white foreign matter. Therefore, if the color of the light source is selected in accordance with the composition of the sheet package, the color of the foreign matter, or the stain, each portion can be identified based on the color intensity or the density distribution. By obtaining the relationship between the light source color and the observed image for the standard sheet packaging sample having no defect as reference data, and comparing the relationship in the sheet packaging to be inspected with the reference data, different types of tablets having different colors can be identified.

Although the color of the light source may be set and fixed in advance,
The optimum color of the light source changes depending on the color of the sheet packaging components, foreign matter, and dirt. In addition, the type of sheet package to be inspected changes, and the optimal light source color may change. For this reason,
It is desirable that the color of the light source can be arbitrarily changed. In this method, a plurality of LEDs (light emitting diodes) or colored beans lights are prepared, and the required color components, typically at least one set of red, green, and blue, are prepared. Are individually controlled to control the emission color components, and adjust the ratio of the emission color components as a whole. Thereby, a desired light source color can be obtained.
Another method is to place a color filter after the illumination. It is also possible to change the color of light to the sheet packaging by taking in and out color filters of different colors.

If a color reflector such as a color half mirror or a color reflector having a reflection component of at least 5% or less under the sheet packaging is used in place of the lower light source, the light corresponding to the color of the color reflector is lowered. Will be illuminated from However, in this case, among the color components of the light source from above, the color components overlapping with the color components of the respective parts of the sheet packaging are transmitted at an intensity corresponding to the transmittance and enter the reflector. Of the color components transmitted by the reflector, only the reflection color component of the reflector is reflected, enters the sheet packaging again, passes through, and is observed as an image by the two-dimensional sensor. Utilizing this, when the reflection color of the color reflector is selected, it is possible to obtain a sheet packaging component portion or a defect in an observation image with a high color difference. This embodiment will be described with reference to FIG.

The color of each part of the sheet packaging is shown in FIG.
The color indicated by. In addition, it is assumed that all of the sub-color components are included in addition to the main color. FIG.
FIG. 4 is a diagram for explaining the principle of an embodiment for increasing color contrast. FIG. 13A is a histogram of each color component of a sheet color, and FIG. 13B is a histogram of a tablet. FIG. 13C is a histogram of each color component of the sheet portion observed when a white reflector is placed below the sheet. Although the whole becomes bright due to reflection, there is no change in the mixing ratio of each color component. On the other hand, the histogram of the tablet area does not change from (b). Next, the reflector is changed to red. At this time, the reflection plate reflects strongly only red, and hardly reflects green and blue. For this reason, red light has strong light returning from the reflection plate and passes through the sheet again. However, observed blue and green light are weak because only light from the light source is directly reflected by the sheet. That is, the red component of the sheet color is relatively emphasized, and blue of the same color as the tablet is reduced, resulting in a histogram in which the red component is considerably strong as shown in FIG. Therefore, the color contrast between the red sheet and the blue tablet is enhanced. On the other hand, if the color of the tablet is red, there is a problem. In this case, the red of the sheet and the red of the tablet are compared, and if the tablet is stronger, the red component of the reflector should be reduced as much as possible to make the red of the tablet relatively stronger.
At this time, both the sheet and the tablet have little green component which is a complementary color of red. In addition, if the amount is almost the same, the red color of the sheet can be reduced and the green color of the sheet can be enhanced by using the green reflector. That is, green is enhanced in the sheet as compared with the tablet, and a strong color contrast can be obtained between the red of the tablet and the green of the sheet.

The following is a summary of such a color contrast enhancement method. The RGB component strengths of the tablet and the sheet are individually compared for each of the RGB components, and the light-transmitting sheet increases the reflectance of the reflection plate with respect to a stronger color component or a color of the same color system, and reduces the color component to a weaker color component. On the other hand, the reflectance of the reflector is made as low as possible. In order to lower the reflectance, it is sufficient that the color component is not given to the reflector. At that time, as described above, if the complementary color component is not included in the color components of the sheet and the tablet, or is substantially the same and the difference is small, the non-same color system, particularly the complementary color component, is used as a reflector. The color contrast is further enhanced and the effect is increased. By the way, this policy can be applied to the case where the sheet is lighter than the tablet for all the RGB colors. That is, the reflecting plate may be white which easily reflects all of RGB. Also, if the sheet is darker than the tablet for all RGB, use black without reflection according to the above policy,
Or remove the reflector. As described above, reflection is such that a transparent material such as a sheet has a higher reflectivity for a strong color component than a non-transmissive material such as a tablet, and has a lower reflectivity for a weaker color component. By using a plate, the color contrast between the transmissive body and the non-transmissive body is increased, and the area classification by color analysis becomes extremely easy. In the embodiment, the color components are classified according to RGB, but are not necessarily limited to RGB. Many methods are known for color classification, and they can be used instead of RGB.

FIG. 14 shows a processing procedure for determining the reflector color in the above embodiment. In FIG. 14, C represents a color component, s represents a sheet, and T represents a tablet. H represents a complementary color. The processing shown in the figure is performed for each color component, and the combination of the colors is determined. That is, when the color component of the sheet is larger than the color component of the tablet (step 1).
01), and further emphasize the color components of the sheet (step 106). In the opposite case, it is determined whether or not to consider a complementary color (step 102).
when t or Hs = H _T (step 103), emphasizes the complementary color of the sheet (step 104). If not taken into consideration the complementary color, or if not Hs = H _T is color reduction color component of the sheet (step 105). In the case of the RGB classification, this process is repeated three times to determine each of the RGB color components. When the determination regarding the complementary color is not performed, the determination result may be regarded as N and the determination may be passed. Reflector mirrors, half mirrors, reflectors, and color reflectors (hereinafter simply referred to as reflectors)
Specular reflection occurs on the surface of the camera, and many strong highlights and ghosts may occur on the image, or a part of the camera, the surrounding environment, or the sheet package may be imaged on the camera and appear on the image. As a countermeasure, it is effective to make the surface of the reflector a light diffusing surface with fine irregularities or the like. Also, when the field of view is wide, shading tends to appear remarkably,
In order to reduce this, it is effective to make the surface of the reflecting plate entirely concave. Since the light diffusing surface has a Lambertian reflection direction distribution, a concave surface may be provided to cancel this effect.

When the tablet surface has a mirror surface, it is easy for the light source and the camera to appear in the image.
For this reason, it is necessary to separate the camera from the optical path from the light source and the specular reflection optical path. FIG. 15 is a diagram showing an embodiment of the arrangement of the light sources. In the space between the camera 11 and the sheet packaging 16, the light source is arranged in a cylindrical shape. The environment other than the light source is surrounded by the black plate 12. Also, for the light source,
A two-dimensional array 14 of LEDs is used, and a ground glass or a white transmission diffuser is provided on the front surface thereof. With such an arrangement, it is possible to prevent the light source from being reflected on the camera 11 and becoming a ghost. In the embodiment, the light source is arranged in a cylindrical shape, but the light source is not necessarily limited to the shape. Further, the light source is not limited to the LED array 14, and may be, for example, an array of color miniature lamps. When a reflector 17 is arranged below the sheet packaging 16 and light is irradiated from above, a shadow due to a tablet or a foreign substance is observed on the reflector 17. When this shadow is observed by the camera 11, it greatly hinders defect detection. Therefore, as a measure for preventing a clear shadow from being observed, it has been clarified by an experiment that it is sufficient to sufficiently separate the sheet package 16 and the reflection plate 17.
Depending on the characteristics of the camera lens, the arrangement of the camera 11, and the arrangement of the light sources, the distance was generally 10 mm or more.

As described above, in the present invention, since the wrapped portion, the sheet portion, and the pocket portion have different reflectances and transmittances, the brightness distribution observed by the television camera is different between the reflection type and the transmission type. The reflectivity and transmissivity differ greatly depending on the type, size, and position of the foreign matter even for the defective portion. Therefore, the reflection image and the transmission image have different brightness distribution characteristics. The present invention makes full use of this property. In the present invention, the reflection type and the transmission type are used simultaneously, in which the observation image in the reflected light and the observation image in the transmitted light are input without changing the positional relationship between the camera and the packaging sheet. In order to use the method of detecting the defect by obtaining the logical correlation in the above, the attached foreign matter, the mixed foreign matter, the deformation of the packaged part, the fragment, the dirt, and the smaller, It is possible to identify and detect very fine hair, fibers, and the like with high accuracy. In addition, in order to increase the efficiency of simultaneous use of the reflection type and the transmission type, as described above, simultaneous input of the reflection type and the transmission type under the limited color illumination conditions enables switching between the two types and the multiple images. It is possible to avoid the complexity of the device due to the input, and also to avoid the defect detection omission and false defect output due to the deviation of the local position correspondence between the reflected image and the transmitted image. Can be inspected.

Although two band-pass limited color filters are used in the embodiment, a low-pass or high-pass limited color filter may be used. Further, in the embodiment, a color limiting filter that passes green and red wavelengths is used, but other color combinations may be used. According to the color of the sheet or the color of the tablet itself, a limited color filter is selected so as to obtain the best contrast. Instead of a color filter, a light source having a different emission wavelength, such as a light emitting diode capable of emitting various wavelengths, may be used. In the embodiment, a television camera is used to obtain an image. However, a two-dimensional sensor such as a far-infrared camera, an X-ray camera, and a silver halide film can be used. Alternatively, a two-dimensional image may be obtained by scanning a line sensor. This case is also regarded as a kind of two-dimensional sensor. The two-dimensional sensor includes a monochrome sensor and a color sensor. In the present invention, the monochrome sensor and the color sensor are collectively called a two-dimensional sensor or a camera. On the other hand, in the embodiment, the position of the camera is set above the packaging sheet. However, it goes without saying that there is no problem even if the camera is arranged upside down or rotated in the rotating direction. Furthermore, although the present invention has been described with reference to the inspection of defects occurring in the tablet packaging process, the present invention is not limited to this, and can be applied to the inspection of various packaged parts.

[0029]

As described above, according to the present invention,
The packaging sheet is illuminated sequentially or simultaneously from above and below, and observed with a TV camera to obtain a reflected image and a transmitted image. Since a code representing the correlation is formed and the defect is detected from the code, the detection process is extremely clear and simple, and the defect can be detected simply and with high accuracy. In addition, by proposing a method in which regions are divided and codes of adjacent regions are added, defects can be classified. In addition, by installing a reflection plate or a half mirror immediately below the packaging sheet, it becomes possible to detect the mixing of extra-fine hair or fibers. Furthermore, by proposing a method of simultaneously inputting a reflection image and a transmission image illuminating the inspection object with two color-limited lights as one image, time control of the light source becomes unnecessary and the number of input images is reduced by half. Therefore, defect detection can be performed easily, in a short time, and stably. Furthermore, a method for detecting a defect without separating a reflected image and a transmitted image is disclosed, so that it is possible to cope with a case where separation is difficult. In addition, the RGB component intensities of the tablet and the sheet are individually compared for each of the RGB components, and the light-transmitting sheet increases the reflectance of the reflector for a stronger color component or a color of the same color system, and reduces the weak color. Since the reflectance of the reflection plate can be made as low as possible with respect to the component, the color contrast can be enhanced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of detecting a defect from two image data according to an embodiment of the present invention.

FIG. 2 is a plan view showing the structure of a packaged tablet to be inspected according to the present invention.

FIG. 3 is a sectional view of a pocket portion to be inspected according to the present invention.

FIG. 4 is a diagram showing types of defects to be inspected according to the present invention.

FIG. 5 is a diagram for explaining how bright each defect is observed in an input image in the present invention, and is a schematic diagram when a tablet is observed from above.

FIG. 6 is a transmission diagram when the package sheet is illuminated from below and observed with an upper camera in the present invention.

FIG. 7 is an explanatory diagram of a method for detecting an extremely fine defect or stain-like stain.

FIG. 8 is a code diagram in a case where the quantization of the reflection image and the transmission image is performed at 4 gradations and 3 gradations, that is, the coding method of the present invention.

FIG. 9 is a structural view of a sheet packaging inspection apparatus according to a second embodiment of the present invention.

FIG. 10 is a characteristic diagram in the case where inspection is performed while allowing overlap of light transmission wavelength regions according to the present invention.

FIG. 11 shows the third embodiment of the present invention, and is a diagram showing detection probabilities when a dimmer is connected to a power supply unit.

FIG. 12 is an explanatory diagram showing an embodiment using colors in the present invention.

FIG. 13 is a diagram of an embodiment showing the principle of increasing color contrast.

FIG. 14 is a flowchart illustrating a processing procedure for determining a reflector color according to the present invention.

FIG. 15 is a perspective view showing an embodiment of an arrangement of light sources.

[Explanation of symbols]

T: tablet, P: pocket, S: sheet, M: half mirror, 1: packaging sheet, L: incident light, R: reflected light, 2
... color camera, 3,5 ... light source, 4,6 ... color filter,
7 ... Color separation circuit, 11 ... Camera, 12 ... Black plate, 13 ...
Specular reflection optical path boundary, 14 ... LED array, 15 ... Outer frame,
16: sheet packaging, 17: reflection plate.

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[Procedure amendment]

[Submission date] September 21, 1999 (September 9, 1999
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

5. The sheet packaging inspection device according to claim 1, wherein at least one of the first light source and the second light source has a change in illumination intensity. A dimming device that enables the optical filter to change the transmission amount or the transmission wavelength band, and adjusts the ratio of the reflected light amount and the transmitted light amount according to the color distribution and the reflectance and the transmittance of the packaging sheet. A sheet packaging inspection apparatus, wherein the light source adjusts the color distribution of reflected light or transmitted light in addition to or instead of adjusting the ratio of the amount of reflected light to the amount of transmitted light.

6. The sheet packaging inspection apparatus according to claim 5 , wherein the light source includes a plurality of light sources having different coloring characteristics, and controls the current of each light source of the light source. A sheet packaging inspection device for adjusting or changing the emission color characteristic or wavelength characteristic of the sheet.

7. The sheet packaging inspection device according to claim 1, wherein the half mirror having a reflectance of at least 5% or more.
That the reflection plate is disposed directly below the packaging sheet, or
Instead of the second light source, the reflectance is at least 5% or more.
Having a half mirror or a reflection plate directly below the packaging sheet
Sheet wrapping inspecting device being characterized in that disposed.

8. The sheet packaging inspection apparatus according to claim 7 , wherein the half mirror or the reflection plate uses a color half mirror or a color reflection plate having a reflection characteristic depending on a color or a wavelength of incident light, and the color characteristic is used. Is a sheet packaging inspection apparatus characterized in that a color distribution or a density distribution of each part in an observation image is selected or changed so that the color contrast of each part is enhanced by enhancing, reducing or changing the color.

9. The sheet packaging inspection apparatus according to claim 8 , wherein the color of the color half mirror or the color reflector is:
A sheet packaging inspection apparatus characterized in that the color components to be emphasized in the observation image area of the light transmitting portion of the sheet packaging are increased, and the color components are reduced and compounded for the color components to be reduced, and are combined.

10. The sheet packaging inspection device according to claim 8 , wherein the color of the color half mirror or the color reflector is:
A sheet packaging inspection apparatus, wherein a color component to be emphasized in an observation image area of a light transmitting portion of the sheet packaging is mixed with a complementary color component of a color component to be reduced.

In the sheet wrapping inspecting device according to claim 11 according to claim 7 or 8, wherein the reflecting plate and the half mirror according to claim 7, and the color half mirror and color reflector as recited in claim 8, the surface Is a light diffusing surface or a concave or convex surface.

12. The method according to claim 1, 2, 3, or 4.
3. The sheet packaging inspection device according to claim 1 , wherein at least one of the first light source and the second light source is light.
A sheet packaging inspection apparatus characterized in that the source is located at a position between the camera and the sheet packaging that is out of the line of sight of the camera, and a specular reflection image component from the sheet packaging is reduced.

In the sheet wrapping inspecting device according to claim 13 according to claim 7 or 8, the reflection plate and the half mirror according to claim 7, and 請
The color half mirror and the color reflector according to claim 8 ,
A sheet packaging inspection device, which is separated from the sheet packaging by 10 mm or more.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

FIGS. 5 and 6 are diagrams for explaining how bright each defect is observed in an input image in the present invention. FIG. 5 schematically shows an image when the tablet is observed from above. Note that a bright spot on the image is expressed as white, and a dark spot is expressed as black. Tablet T,
Only highlight F and white defect H1 are observed white. G
2 is observed black on a white background. As described above, I and N have a high risk of being overlooked due to low contrast in a reflection image, and are likely not to be detected in a transmission image due to diffraction development or a small transmittance difference. The above countermeasures will be described with reference to FIG. In the present invention, the half mirror M is provided directly below the packaging sheet 1. In addition, as shown in FIG.
In addition to disposing the first light source 3 and the second light source 5,
When a half mirror M (or a reflection plate) is arranged,
Half mirror M (or reflection) instead of second light source 5
Plate). Part of the light L passing through the sheet portion is reflected by the half mirror M, and returns upward as a reflected light ray R. However, since light does not return at the place where the small defect I exists, the light is darker than the sheet portion, and therefore, the contrast of the defect is increased and the defect can be identified. In FIG. 5, for this reason, I and N are displayed in stronger black. According to the experiment, the reflectance of the half mirror was required to be 5% or more. Also, ground glass having surface reflection may be used as a half mirror in some cases. FIG.
Is a transmission image when illuminated from below the packaging sheet and observed with a camera above. Tablet T, defects H1 and H2 are observed in black. Highlights F, extra-fine hair and fibers I often do not appear in transmission images.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G051 AA02 AB02 AB20 BA01 BA04 BB01 BB11 CA03 CA06 CB01 CB02 CC07 EA11 EA16 EA17

Claims (11)

[Claims] 1. A sheet packaging inspection device for detecting a defect such as a mixed foreign substance, damage, or dirt present in a packaging sheet including a part to be packaged and a packaging sheet, wherein the inspection apparatus is arranged above the packaging sheet. A first light source for irradiating the packaging sheet; a two-dimensional sensor disposed above the packaging sheet for observing the packaging sheet; a unit for inputting a reflection image from above the packaging sheet; And a means for inputting a transmission image irradiated from below the packaging sheet, wherein the reflection image and the transmission image are respectively binarized or multi-valued. Calculate the values to calculate a plurality of binary or multi-valued images, generate a code distribution image indicating the density distribution of the plurality of images, and then convert the code distribution image into a sheet-wrapped component or a wrapping sheet. Existence Detecting the above-mentioned defect, or calculating the density distribution of single or plural colors for the reflection image or the transmission image or both images to obtain a single or plural gradation distribution image of the reflection image or the transmission image After that, a color code distribution image or a gray code distribution image is generated, and inspection of the shape and color of a sheet or a part packaged from the sheet from the color code distribution image or the gray code distribution image, defects such as foreign matter and dirt A sheet packaging inspection device, characterized by detecting the following. 2. A sheet packaging inspection apparatus for detecting defects such as contaminants, damage, dirt, etc., present in a packaging sheet comprising a part to be packaged and a packaging sheet, the inspection apparatus being disposed above the packaging sheet, A first light source that irradiates the packaging sheet; a second light source that is disposed below the packaging sheet and irradiates the packaging sheet; a two-dimensional sensor that observes the packaging sheet; and inputs an image of the packaging sheet. Means for simultaneously turning on the light sources 1 and 2 to perform binarization or multi-value processing on the density distribution of the input image, and then present the parts and the packaging sheet which are packaged by a logical operation. Detecting the defect described above, or calculating the density distribution of one or more colors for the reflection image or the transmission image or both images to obtain a single or multiple colors of the reflection image or the transmission image. Obtain a number of color distribution images or grayscale distribution images, and then inspect the shape or color of parts or sheets packed in sheets by logical operation from the color distribution images or grayscale distribution images, and detect defects such as foreign matter and dirt A sheet packaging inspection device. 3. The sheet packaging inspection device according to claim 1, wherein at least one of the first light source and the second light source is capable of changing illumination intensity. An optical filter capable of changing a transmission amount or a transmission wavelength band; adjusting a ratio of a reflection light amount and a transmission light amount according to a color distribution and a reflectance and a transmittance of the packaging sheet; A sheet packaging inspection apparatus characterized by adjusting the color distribution of reflected light or transmitted light in addition to or instead of adjusting the ratio of the amount of light. 4. The sheet packaging inspection apparatus according to claim 3, wherein the light source includes a plurality of light sources having different coloring characteristics, and controls the current of each light source of the light source. A sheet packaging inspection device for adjusting or changing the emission color characteristic or wavelength characteristic of the sheet. 5. The sheet packaging inspection device according to claim 1, wherein the reflection is provided in addition to each of the means according to claim 1 or in place of the second light source. A sheet packaging inspection device, wherein a half mirror or a reflection plate having at least 5% or more of components is disposed directly below the packaging sheet. 6. The sheet packaging inspection apparatus according to claim 5, wherein the half mirror or the reflection plate uses a color half mirror or a color reflection plate having a reflection characteristic depending on a color or a wavelength of incident light, and the color characteristic is used. Is a sheet packaging inspection apparatus characterized in that a color distribution or a density distribution of each part in an observation image is selected or changed so that the color contrast of each part is enhanced by enhancing, reducing or changing the color. 7. The sheet packaging inspection apparatus according to claim 6, wherein the color of the color half mirror or the color reflector is:
A sheet packaging inspection apparatus characterized in that the color components to be emphasized in the observation image area of the light transmitting portion of the sheet packaging are increased, and the color components are reduced and compounded for the color components to be reduced, and are combined. 8. The sheet packaging inspection device according to claim 6, wherein the color of the color half mirror or the color reflector is:
A sheet packaging inspection apparatus, wherein a color component to be emphasized in an observation image area of a light transmitting portion of the sheet packaging is mixed with a complementary color component of a color component to be reduced. 9. The sheet packaging inspection device according to claim 5, wherein the half mirror and the reflection plate according to claim 5 and the color half mirror and the color reflection plate according to claim 6 are arranged such that: A sheet packaging inspection device, wherein the surface is a light diffusing surface or a concave or convex surface. 10. The sheet packaging inspection device according to claim 1, wherein at least one of the first light source and the second light source according to claim 1 or 2. 6. The sheet according to claim 5, wherein the upper light source used in claim 5 is disposed at a position out of the line of sight of the camera between the camera and the sheet package, and reduces a specular reflection image component from the sheet package. Packaging inspection equipment. 11. The sheet packaging inspection apparatus according to claim 5, wherein the half mirror and the reflection plate according to claim 5, and the color half mirror and the color reflection plate according to claim 6,
A sheet packaging inspection device, which is separated from the sheet packaging by 10 mm or more.