JP2001175856A - Visual inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual inspection device which can accurately detect properties of an article hard to recognize even with the naked eye like curry liquid sticking on a retort curry pack. SOLUTION: The pack 1 which is filled with curry liquid and has its opening part heated and sealed is lightened up and its external shape is detected by a color CCD camera 5; and a color image extracting device 7 extracts only a color image corresponding to the curry liquid from the color image information and various parameters of the color image are matched by pixels against parameters of the curry liquid. The color CCD camera 5 has increased spectral characteristics of red that the curry liquid has. Further, a lighting device 8 uses a fluorescent lamp which has the power spectrum of wavelength nearby 650 nm corresponding to read increased by adjusting a fluorescent agent to color the red of the curry liquid intensely. When the frequency band wherein the power spectrum is emphasized is too narrow, the current liquid possibly does not color intensely or widely, so a fluorescent lamp which has continuous spectra is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an appearance inspection apparatus for capturing color information of the appearance of an article, extracting necessary color information therefrom and determining the properties of the article.

[0002]

2. Description of the Related Art For example, as a method of capturing color information of the appearance of an article as a color image and extracting necessary color information from the color image, for example, "Image processing application technology" by Hiroshi Tanaka (Industry Research Institute Co., Ltd.) Chapter 4 Color Image Processing Techniques (p85-p85)
As described in p105), for example, a so-called RGB (red-green-blue) three-dimensional color image is converted into a uniform color conversion image such as L ^* a ^* b ^* or a brightness, hue, color tone, and saturation conversion image such as LHTC. The conversion is performed so that pixels corresponding to those of the target color to be extracted are selected. That is, the color properties of the obtained color image are finely classified, and those are compared pixel by pixel with those of the target color to extract a pixel that matches or almost matches. In the case of a general visual inspection device, the properties of an article are determined from the extracted color image.

[0003]

However, when the information of the color to be detected is extremely weak, for example, in the case of a light-colored liquid that is difficult to be recognized by the naked eye or a light-colored difference between similar colors, detection is difficult. The extraction accuracy of the target color to be used is low, and the property of the article cannot be accurately determined. The present invention has been developed in order to solve the above-mentioned problems, and information on a color to be detected is extremely weak. For example, it is possible to accurately extract color information that cannot be recognized by the naked eye and determine the properties of an article. It is an object of the present invention to provide a visual inspection device capable of performing the above-mentioned operations.

[0004]

In order to solve the above-mentioned problems, a visual inspection apparatus according to claim 1 of the present invention captures color information of the appearance of an article and extracts necessary color information therefrom. A color image information detecting means for detecting color information of the external appearance of the article as color image information; and a color image information detecting means for extracting the color image information from the color image information detected by the color image information detecting means. Color image extracting means for extracting a color image corresponding to power color information; determining means for determining the properties of the article from the color image extracted by the color image extracting means; Illuminating means for irradiating light to the appearance of the article to detect color image information, wherein the illuminating means irradiates continuous light having a spectral characteristic with a continuous spectrum and the frequency of the color information to be extracted Band power specs Le is characterized in that is strengthened.

According to a second aspect of the present invention, in the visual inspection apparatus according to the first aspect, the color image information detecting means includes a frequency of the color information to be extracted among the color images to be detected. It is characterized in that the band detection ability is enhanced.

[0006]

Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing one embodiment in which the appearance inspection device of the present invention is applied to a retort curry pack. In this embodiment, a curry liquid is filled into a bag-like pack 1 sealed on three sides, and thereafter, the opening of the bag-like pack 1 is polymerized, and the portion is further heat-sealed. The inspection device mainly inspects the sealing property of the heat-sealed portion, and inspects, for example, whether the seal portion is wrinkled and whether the curry liquid leaks (is not attached).

The sealed pack 1 is a belt conveyor 2
It is conveyed over the top and slightly pressed to make it flat for easy inspection. Next, it is conveyed to the inspection area, where the curry liquid adhesion inspection is first performed, and then the wrinkle inspection is performed. When the two inspections are completed, the pack 1 is further transported on the belt conveyor 2 and the passage of the inspected pack 1 is confirmed by the photoelectric tube 3, and then the next pack 1 is transported to the inspection area.

[0008] Both of the two inspection items are controlled by a controller 3 composed of a personal computer or the like.
Is configured to be read. In the adhesion inspection of the curry liquid, a color CCD camera 5 is used as color image information detecting means.
The color image information of the external appearance of the pack 1 read by the above is cut out by the image freezer 6 and sent to the color image extracting device 7 where the same color image as the curry liquid is extracted and read from the image processing device 4 to the controller 3. The color CCD
In order to make it easier for the camera 5 to read the color image information of the external appearance of the pack 1 and to allow the color image extraction device 7 to easily extract the same color image as the curry liquid, there is provided an illumination device 8 whose frequency characteristics are devised.

On the other hand, the wrinkle inspection is performed by using three monochrome CCD cameras 11, each monochrome image information is cut out by an image freezer 12, and read from the image processing device 4 to the controller 3. The wrinkle inspection performed in the controller 3 will be briefly described, for example, in FIG.
As shown in FIG. 3B, the highlight portion (bright white portion) is erased from the black-and-white image information of the external appearance of the pack 1, particularly, the black-and-white image information of the seal portion through the minimum value filter, and then the ground pattern is removed using the median filter. (Overall pattern). Since the brightness changes sharply at the wrinkled part,
The change in the luminance signal of the smoothed image information is differentiated between adjacent pixels, wrinkles are extracted by extracting only a portion having a large differential value, and further binarized to obtain a wrinkle area or a wrinkle area. The density is calculated to determine whether the wrinkle is appropriate as a product. The wrinkle inspection uses an illumination device 13 different from the curry liquid adhesion inspection.

On the other hand, in the above-described curry liquid adhesion test, R (red), G (green), B (green),
A so-called three-panel color CCD camera 5 is used, which applies and detects one CCD at a time for each of (blue). And
In the controller 3, as shown in FIG.
Converts B color image information into uniform color conversion images such as L ^* a ^* b ^* and brightness, hue, hue, saturation conversion images such as LHTC, and compares each of these parameters with that of curry liquid for each pixel Then, it is determined whether or not the curry liquid is attached.

Among the curry liquids to be filled in the pack 1, the curry liquid having a particularly low concentration has its own color information, in particular, the saturation is weak. For example, when the curry liquid adheres to the pack 1, the color of the base of the pack 1 can be seen through. Therefore, it is difficult to extract a color image.
It was found that the color frequency of the curry liquid that was difficult to detect was slightly reddish. Therefore, in the present embodiment, as shown in FIG.
To enhance the detection ability (sensitivity) of red (R), thereby facilitating extraction of a thin curry solution. Further, since the color develops strongly when light similar to its own frequency band is irradiated, the illumination device 8 that irradiates the pack 1 with light in this curry liquid adhesion test.
For example, instead of a normal fluorescent lamp as shown in FIG. 5a, for example, a slightly reddish fluorescent lamp of a light bulb color as shown in FIG. 5b is used. As is apparent from these spectral characteristics, the fluorescent lamp used in the curry liquid adhesion test of the present embodiment has a pale blue power spectrum in the region of 500 nm or less, which is weaker and more reddish than a normal fluorescent lamp.
The power spectrum in the region of about 50 nm is strong. Such spectral characteristics of the fluorescent lamp can be obtained, for example, by adjusting the fluorescent agent included in the fluorescent lamp.

The curry liquid is reddish, but not a single or narrow color frequency band. Therefore, with a light source having a single or narrow color frequency band such as a laser beam or an LED beam, the curry liquid may not develop a strong color, and therefore the color image may not be reliably extracted. Therefore, by enhancing the power spectrum in the frequency band of the color to be extracted from the light having a continuous spectral characteristic, such as the fluorescent lamp, the color tone in a certain broad range in the vicinity thereof is broadly emphasized. It is done. In other words, by increasing the light energy in the frequency band corresponding to the preview information of the target color to be extracted, it is possible to extract a comparative color over a relatively wide range.

FIG. 6 shows a diagram a and a diagram b, a diagram c and a diagram d,
Separation charts e and f respectively show the detection of the curry liquid at the portions indicated by the arrows. Separation charts a, c, and e are the original images, separation charts b, d, and d. f is a curry liquid extraction image. From these, the appearance inspection apparatus clearly extracts the curry liquid in the original image, in which the curry liquid is thin and the color of the base of the pack 1 is transparent, and is difficult to recognize with the naked eye.

Next, another embodiment of the appearance inspection apparatus of the present invention will be described. This embodiment is an apparatus for detecting a defective portion of a rubber bale (lumps) which is a raw material of, for example, an automobile tire. The rubber veil is originally white and translucent, and a pale yellow portion and a non-transparent white portion are defective portions. Furthermore, although the surface of the rubber veil has irregularities, it is necessary to prevent the shadow of the irregularities from being erroneously recognized as a defective portion. In other words, it is necessary to accurately discriminate subtle color differences and accurately express color differences felt by humans. In addition, such a defective portion needs to be detected on the upper surface and the lower surface of the rubber veil, and the defective portion must be detected while the rubber veil is being conveyed. , Twice as much processing power is required.

FIG. 7 shows the configuration of a visual inspection apparatus for satisfying such conditions. Basic configuration for extracting color information,
That is, the configurations of the color CCD camera 5, the image freezer 6, the color image extracting device 7, the image processing device 4, and the controller 3 are the same as those in the first embodiment, but the processing capacity on the lower surface side of the rubber veil 9 as described above. The two color CCD cameras 5 are arranged on the lower surface side in order to double the value. Note that two color CCD cameras 5 are also provided on the upper side of the rubber veil.
However, for actual detection of a defective portion, only one of the two devices is switched by the switching device 10 and used. The color image information of each color CCD camera 5 can be independently stored as an original image by the image freezer 6.

It is difficult for a general color CCD camera to discriminate a particularly pale yellow portion among the defective portions described above. This is because the spectral sensitivity of the camera is different from the sensitivity (spectral sensitivity) for each color (light wavelength) of the human eye, and the sensitivity on the long wavelength side such as yellow to red is lower than that of humans. ing. Therefore, also in the color CCD camera of the present embodiment, the spectral sensitivity is adjusted by performing the γ correction and the gain adjustment of the R signal, and the detection capability of red is particularly enhanced.

Similarly to the first embodiment, the illumination for irradiating the rubber veil is replaced with, for example, a normal fluorescent lamp as shown in FIG. 8A, and a slightly reddish or bulb color as shown in FIG. 8B. Using a fluorescent lamp. As is apparent from the spectral characteristics, the fluorescent lamp used in the rubber veil defect inspection of the present embodiment adjusted the contained fluorescent agent, and the power spectrum in the region of about 450 nm pale blue was weaker and reddish than the ordinary fluorescent lamp. 600n
The power spectrum in the long wavelength region of m or more is enhanced.
This enhances the light yellow extractability described above.

Then, the controller 3 converts the obtained RGB color image information into L, as in the first embodiment.
^* a ^* b ^*, etc., and converted into brightness, hue, hue, saturation conversion images such as LHTC, etc., and compared each pixel with those set in advance as defective parts, It is determined whether there is a defective part. Further, in the present embodiment, several different colors set in advance as defective portions are sequentially extracted from several channels provided in the color image extracting device, so that various types of defects can be detected. I made it.

FIGS. 9A and 9B show an original image of a rubber veil and an image of a defective portion extracted. In both cases, the white part seen in the defective part extracted image is the defective part, and in the original image, the defective part that is difficult to recognize with the naked eye is clearly extracted. In addition,
In each of the embodiments described above, only the case where the adhesion of the curry liquid, the detection of a defective portion of the rubber veil, and the like are determined as the properties of the article has been described. Further, the optical frequency band to be enhanced by the camera or the illumination is not limited to red, but widely corresponds to the frequency band of the color to be extracted.

[0020]

As described above, according to the appearance inspection apparatus of the first aspect of the present invention, the continuous light having the enhanced power spectrum in the frequency band of the color information to be extracted is illuminated by the illumination means. Irradiates the color image information corresponding to the color information to be extracted from the color image information, and determines the properties of the article from the extracted color image. When there is information, the color information is strongly colored, so that it is easy to extract a color image corresponding to the color information. It is possible to make a determination.

According to the appearance inspection apparatus of the present invention, the ability to detect the frequency band of the color information to be extracted from the color image detected by the color image detecting means is enhanced. Therefore, if the detected color image has a color image corresponding to the color information to be extracted, it becomes easier to extract the color image, and the color information to be extracted is more accurately extracted, and The properties can be determined.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment in which a visual inspection device of the present invention is used in a curry liquid adhesion detection device.

FIG. 2 is an explanatory diagram of wrinkle detection by a wrinkle detection device added to the curry liquid adhesion detection device of FIG.

FIG. 3 is a logic diagram of curry liquid adhesion detection performed by the controller of FIG.

FIG. 4 is an explanatory diagram of spectral sensitivity of a color CCD camera used in the curry liquid adhesion detecting device of FIG.

FIG. 5 is an explanatory diagram of the spectral characteristics of illumination used in the curry liquid applying device of FIG.

FIG. 6 is an explanatory diagram of a curry liquid detected by the curry liquid attaching device of FIG.

FIG. 7 is a schematic configuration diagram of an embodiment in which the appearance inspection device of the present invention is used for a defective portion detection device of a rubber veil.

FIG. 8 is an explanatory diagram of the spectral characteristics of illumination used in the rubber veil defective portion detection device of FIG. 8;

FIG. 9 is an explanatory diagram of a defective portion detected by the rubber bale defective portion detection device of FIG. 8;

[Explanation of symbols]

 1 is a pack (article) 2 is a belt conveyor 3 is a controller 4 is an image processing device 5 is a CCD camera 6 is an image freezer 7 is a color image extraction device 8 is a lighting device 9 is a rubber veil (article) 10 is a switching device

Continued on front page F term (reference) 2G020 AA08 DA02 DA03 DA04 DA22 DA34 DA52 5B047 AA30 AB04 BB01 BC11 DB03 5B057 AA01 BA02 BA11 CA01 CB01 CE05 CE06 CE12 CE18 DA03 DB06 DC25 5C054 CA04 CB00 EA01 EE04 FB03 FC08 HA05

Claims (2)

[Claims] 1. An appearance inspection device which captures color information of the appearance of an article, extracts necessary color information therefrom and determines the properties of the article, and detects the color information of the appearance of the article as color image information. A color image information detecting unit, a color image extracting unit for extracting a color image corresponding to the color information to be extracted from the color image information detected by the color image information detecting unit, and a color image extracting unit Determining means for determining the properties of the article from the color image; and illuminating means for irradiating the appearance of the article with light so that the color image information detecting means detects color image information of the appearance of the article; 3. An appearance inspection apparatus, comprising: irradiating continuous light having a spectral characteristic with a continuous spectrum; and enhancing a power spectrum in a frequency band of the color information to be extracted. 2. The visual inspection according to claim 1, wherein the color image information detecting means has enhanced ability to detect a frequency band of the color information to be extracted among the color images to be detected. apparatus.