WO2008072679A1

WO2008072679A1 - Mark detecting method

Info

Publication number: WO2008072679A1
Application number: PCT/JP2007/073982
Authority: WO
Inventors: Atsuhiko Shinozuka; Sang Il Nam
Original assignee: Sumitomo Chemical Company, Limited
Priority date: 2006-12-12
Filing date: 2007-12-06
Publication date: 2008-06-19
Also published as: JP2008146432A; TW200839222A

Abstract

Provided is a method for detecting a mark applied on a resin film in colors excluding black colors. The resin film having the applied mark is irradiated with light, the transfer image or the reflection image are picked up by a color CCD camera, and RGB signals from the color CCD camera are processed by an HSV color system. When the ranges of hue (H), chroma (S) and luminance (V) are indicated by 256 gradations, the mark is detected based on a pixel that has a hue (H) within a range set in accordance with the color of the applied mark, the chroma (S) within a range of 100-225 and the luminance (V) within a range of 220-255.

Description

Specification

Mark detection method Technical Field

The present invention relates to a method for detecting a mark applied to a resin film. Specifically, the present invention relates to a method of detecting a mark provided to indicate a defect position of a resin film such as an optical film. Background art

A resin film such as an optical film is usually manufactured in a long strip shape with a constant width, subjected to various treatments in that state, wound on a roll, and stored as a raw film. At a later date, a sheet-shaped film having a predetermined shape is cut out from the raw film according to the product specifications (see, for example, Japanese Patent Laid-Open No. 2000-0130 070).

The defect detection of the resin film is usually performed in a belt-like state, and a mark is given by a felt pen or an ink jet so that the defect part can be easily identified. If there is a defect in the cut sheet film, even if it is difficult to identify with the naked eye, a mark is given and it can be easily identified and easily removed from the product.

On the other hand, in order to automatically remove a single-wafer film having a cut-out defect, and to efficiently cut out a single-wafer film avoiding the defect, the mark applied to the resin film is automatically detected with high accuracy. A method is desired.

As a mark inspection method, a method for determining the color and size of a mark from three types of images obtained by binarizing R, G, and B signals from a color camera is known (JP-A-6-5). (See 0 7 3 5).

However, with this conventional method, the detection accuracy decreases when the mark is faint or faint due to vibration during transport of the resin film, fluctuations in pen pressing pressure, ink consumption, etc. If the resin film has a color pattern, the mark may not be detected. There is a need for a method for detecting the mark. An object of the present invention is to provide a method for accurately detecting marks provided on a resin film in order to indicate a defect position or the like.

As a result of intensive studies on a method for accurately detecting a mark applied to a resin film in order to indicate a defect position or the like, the present inventors irradiate light to a resin film provided with a color mark except for a black color system. The transmitted image or reflected image is captured with a color CCD power camera, and the RGB signal obtained from the color CCD camera is processed with the HSV color system, and the resulting hue (H), saturation (S), and brightness ( The range of V) is expressed in 256 gradations, the range is set according to the color of the mark assigned by hue (H), the saturation (S) is in the range of 100 to 225, and the brightness (V) It was found that by detecting the mark based on the number of pixels satisfying the range of 220 to 255, it was possible to detect the assigned mark with high accuracy, and the present invention was achieved. Disclosure of the invention

That is, the present invention is a method for detecting a mark imparted to a resin film with a color other than black, and irradiates the resin film with the mark with light, and transmits the transmitted image or reflected image as a color CCD. The image is captured by the camera, the RGB signal from the color CCD camera is processed in the HSV color system, and the resulting hue (H), saturation (S), and brightness (V) ranges are each expressed in 256 tones. Range set according to the color of the mark assigned by hue (H), saturation (S) in the range of 100 to 225, and brightness (V)

This is a mark detection method for detecting the mark based on the number of pixels satisfying the range of 220-255.

Also, the hue (H) range expressed in 256 gradations is 0 to 20 or 235 to 255 for red marks, 135 to 175 for blue marks, and 135 to 175 for green marks. This is a method for detecting the marks 75 to 115.

Further, the detection of the mark that is determined to be a mark provided when the area corresponding to the mark obtained from a pixel that satisfies the range is 70% or more of the set area. W

Three

It is a way out. Brief Description of Drawings

FIG. 1 is a schematic view showing an example of an apparatus used in the present invention. Explanation of symbols

1 Resin film

2 rolls

3 Film cutting device

4 sheet film

5, 6 Conveyor

7 Support roll

8 Sorting device

9 Light source

1 0 Color C C D Camera

1 1 Image processing device

1 2 Control unit

1 3 Recorder Best mode for carrying out the invention

Examples of the resin film include, but are not limited to, optical films such as polarizing films, retardation films, and optical compensation films, polyolefin films, acrylic films, and polysulfone films.

In the present invention, a mark imparted to the resin film with a color other than black is detected. The marking method is performed by a publicly known method, and is usually performed manually using a felt-tip pen, an ink jet or the like, or automatically by a method described in, for example, Japanese Patent Laid-Open No. 2 0 1-3 0 5 0 70 Done.

Black and gray black marks are removable deposits other than the detection target mark. Since they are sometimes detected, they are given marks of colors other than black, such as red, blue, and green, which are difficult to detect. If the resin film has a color pattern, a mark different from the pattern color is given.

The shape of the mark is not particularly limited, but usually a linear mark is given.

In the same way as when detecting defects in a resin film, the applied mark is imaged by irradiating the resin film with light and capturing the transmitted or reflected image with a power CCD camera. Examples of light include visible light and ultraviolet light. If the mark is applied with a highlighter, irradiate with ultraviolet light. As the light source, a white lamp, a fluorescent lamp, an ultraviolet lamp, etc. are used.

Since the black and white camera may not be able to detect the mark depending on the color of the mark, in the present invention, a mark other than the black system is added and the image is taken with the color CCD camera. When the resin film is transparent, the transmission image or reflection image is captured with a color CCD, and when it is opaque, the reflection image is captured.

RGB signal from a color CCD camera is processed with the HSV color system using an image processor, and the hue (H), saturation (S), and lightness (V) ranges of the pixels satisfy the set range. A mark is detected based on the pixel to be processed. Image processing can be performed using a commercially available device.

Since the color of the assigned mark is known in advance, the hue (H) range is set according to the color of the assigned mark. The range is expressed in 256 gradations (the same applies hereinafter). For example, in the case of a red mark, 0 to 20 or 235 to 255, preferably 0 to 9 or 250 to 255, in the case of a blue mark Is 135 to 175, preferably 141 to 169, and in the case of a green mark, is 75 to 1 15, preferably 80 to 108. Pixels that do not satisfy these ranges are not pixels that make up the color mark to be detected.

The saturation (S) range is 100 to 225, preferably 105 to 220, regardless of the mark color, and the brightness (V) range is 220 to 255, preferably 245, regardless of the mark color. ~ 255. If you narrow these ranges, Detection of a rubbed mark is insufficient.

The area corresponding to the mark is obtained from the pixels satisfying the above range. Since the size of one pixel is known in advance, the area is obtained from the number of pixels. Usually, the area of the assigned mark or the area of the mark portion to be photographed is known in advance, and this area is set as the set area.

It is determined that the mark is provided when the area obtained from the pixel is 70% or more, preferably 80% or more of the set area. Although it is possible to determine by determining the shape of the mark from the pixel, a method for determining the area is easy and preferable.

FIG. 1 is a schematic diagram showing an example of an apparatus used in the present invention. The defect detection device and marking device not shown in the preceding figure detect defects in the resin film, mark the resin film with a color other than black to indicate the position of the defect, wind it up on a roll, and store it. ing.

Unwind the resin film 1 from the roll 2 where the stored resin film 1 with the mark attached is wound, and transport it to the film cutting device 3 (in the direction of the white arrow). The cut sheet 4 is transported to the sorting device 8 by the transport conveyors 5 and 6 and the support roll 7.

Light is emitted from the light source 9 disposed between the support rolls 7, and the transmitted image is captured by the color CCD camera 10. RGB signal obtained from a color CCD camera is processed with the HSV color system using the image processor 1 1, and the range of hue (H), saturation (S) and lightness (V) of the resulting pixel is marked with a red mark. When assigned, each is expressed in 2 5 6 tones, and the hue (H) ranges from 0 to 20 or 2 3 5 to 2 5 5 and the saturation (S) ranges from 1 0 0 to 2 2 5 The mark is detected based on a pixel whose range and brightness (V) satisfy the range of 220 to 25.sub.5. If the area corresponding to the mark obtained from a pixel that satisfies the above range is 70% or more of the set area, it is determined that the mark is given.

The processing data is stored in the control device 12 and displayed on the recorder 13 if necessary. A sheet film that is determined to have a mark is a sheet film that is not marked in the sorting device 8 based on the conveyance speed of the resin film from the conveyance speed detection means (not shown). And sort. Examples of the present invention will be described below, but the present invention is not limited to these. Example 1

In the vicinity of a defect detected by inspection of a polarizing film (manufactured by Sumitomo Chemical Co., Ltd.), a linear mark (length: about 23 mm, width: about 2 mm) with a red felt pen (manufactured by Pentel) The area was about 69 mm ² ).

White light (light source: fluorescent lamp surface light source, manufactured by Cabin Co., Ltd.) is irradiated from the bottom of this film, and the transmitted image is viewed from above. The image was taken with a color CCD camera (2 million strokes) and the RGB signal was processed with the HSV color system. It should be noted that only the tip of the mark (length 2.5mm) was taken.

Note that the hue (H) setting range expressed in 256 gradations is 0 to 20 or 235 to 255, the saturation (S) setting range is 100 to 225, and the lightness (V) setting range is

220-255.

The set area corresponding to the mark to be photographed was 5 mm ² (width 2111111 length 2.5111 m).

As a result, the above-mentioned imparted mark could be detected. The hue (H) range of the obtained pixels is 254 to 255, the saturation (S) range is 173 to 213, and the lightness (V) range is 225 to 255, each satisfying the setting range. there were. The area corresponding to the mark was calculated from the area (0.052 mm ² ) of the pixel that satisfies this setting range and the number of pixels, and it was 4 mm ² , which was 80% of the set area 5 mm ² . When the hue (H) setting range was 253 to 254, the area obtained from pixels satisfying this range was less than 70% of the setting area, and the assigned mark could not be detected. In addition, when the saturation (S) setting range was 153 to 193, the assigned mark could not be detected. Example 2

The red felt pen used in Example 1 was consumed to give a thin, linear mark (length: about 23 mm, width: about 2 mm, area: about 69 mm ² ), Marks were detected in the same manner as in Example 1.

As a result, it was possible to detect the given mark. The range of hue (H) of the obtained pixel is 2 5 4, the range of saturation (S) is 1 7 4 to 1 9 7, and the range of lightness (V) is 2 3 4 to 2 4 9 Yes, each satisfied the set range. Area of the pixel that satisfies the specified range of this ^{(0. 0 5 2 mm 2} ) with a 4 mm ² was determined and the area corresponding to the mark from that number was 80% of the set area 5 mm ² . If the saturation (S) setting range is 1 5 4 to 1 7 7, the area obtained from pixels that satisfy this range is less than 70% of the setting area, and the assigned mark can be detected. There wasn't. In addition, when the brightness (V) setting range was 2 14 to 2 29, it was not possible to detect the assigned marks. According to the present invention, it is possible to accurately detect a mark given to a resin film even when the mark is thin or faint.

Claims

The scope of the claims

1. A method for detecting marks on a resin film that has a color other than black, and irradiating the resin film with the mark with light and capturing the transmitted or reflected image with a power CCD camera. The RGB signal from the CCD camera is processed in the HSV color system, and the range of hue (H), saturation (S), and brightness (V) of the resulting pixel is expressed in 256 gradations respectively. Mark detection that detects the mark based on pixels that satisfy the range set according to the color of the mark assigned by, saturation (S) in the range of 100 to 225, and brightness (V) in the range of 220 to 255 Method.

2. The range of hue (H) in 256 gradations is 0 to 20 or 235 to 255 for red marks, 135 to 175 for blue marks, and 75 for green marks. The mark detection method according to claim 1, wherein the mark detection method is.

3. The mark detection method according to claim 1, wherein when the area corresponding to the mark obtained from a pixel satisfying the range is 70% or more of the set area, the mark is determined to be provided.