JP3487760B2 - How to inspect a disk - Google Patents

Description

Detailed Description of the Invention

[0001] The present invention, CD, PD, relates to an optical reflective disk as a disk-type data storage media of DVD, etc. is relates <br/> the inspection how the disc to detect a defect.

[0002]

2. Description of the Related Art Conventionally, the method and apparatus disclosed in Japanese Patent Application Laid-Open No. 03-172527 have been used to inspect these disks. This method uses an optical disk playback device with an optical pick and performs playback operations one by one for each disk to be inspected.
The quality of the disc is detected with high accuracy.

[0003]

By the way, there are various types of reproducing systems for discs. Therefore, the above-described method using the reproducing device requires the same number of reproducing devices according to the type of the disc. Therefore, a large amount of capital investment was required to inspect various discs.
Further, if the discs are reproduced one by one for the inspection, the inspection efficiency is low and the cost is high because the inspection for each disc takes several tens of minutes. In order to cope with the increase in the number of disks-type data storage media that have been produced in response to the recent increase in demand, inspecting by using a plurality of playback devices at the same time further increases the equipment cost, resulting in a higher cost.

The present inventors have made various studies in order to solve these problems. Considering that the image data of the surface to be inspected is subjected to image processing to detect a defect by image recognition, a grayscale image obtained by receiving light is binarized and detected as in a normal image processing. As a result, the binarized image C as shown in FIG. 6 is obtained, and the regular pattern a and the noise image b provided for reading and writing on the disc are detected, and the regular pattern a and the noise image b are regular. The pattern a can be detected by a pattern matching method or the like, and a noise image b that does not match the pattern a can be easily detected as a defect. However, 1 of the regular pattern a
Although there is a noise image b, it is not detected and is erroneously detected. Further, since the disc is often formed by laminating a plurality of layers, the image processing and image recognition as described above may cause erroneous detection by overlooking defects such as small holes and light transmitting portions. Moreover, the types of defects include holes, light-transmitting parts, foreign matters, scratches, stains, etc., which cause noise during reproduction, and these must also be distinguished and detected with high accuracy by distinguishing them from various regular pattern images. However, this has not been fully answered.

An object of the present invention, while satisfying the inspection accuracy, is to provide an inspection how the disks that can be inspected at high speed than a plurality of types of disks in the prior art.

[0006]

In order to achieve the above object, the disk inspection method of the invention according to claim 1 is such that the surface to be inspected of the light-reflecting disk is from one side of the normal line. Along with irradiating the illumination light, the reflected light from the surface to be inspected is received on the side opposite to the normal line to obtain a grayscale image of the surface to be inspected , and the grayscale image is image-processed to perform image recognition. of
Set the pattern neighborhood including the pattern neighborhood and
Except for the normal pattern recognized in the image,
On the outside, without the operation to remove the regular pattern,
Perform the operation to detect the noise image of the fall by image recognition.
The main characteristics are and. In the invention according to claim 2, the transmitted light from the disc is received on the side of the disc opposite to the surface to be inspected, and the defect of the hole or the transparent portion is detected by the transmitted light .
Is a further feature. In addition, these smells
The incident angle of the illumination light is 10 ° to 80 ° with respect to the surface to be inspected.
It is preferable to set it to about °.

According to the first aspect of the present invention, the light-reflecting surface to be inspected is irradiated with illumination light from one side of the normal line and the reflected light is received on the side opposite to the normal line, whereby the light is reflected. It is possible to obtain a grayscale image according to the difference in the reflection condition of the inspected surface having reflectivity. The grayscale image data includes various regular pattern images and various noise images. By performing image processing on the grayscale image data, specifically, the regular pattern is printed on the surface to be inspected.
This regular pattern in the grayscale image, if
By recognizing the image and distinguishing it from defects,
Is not detected as a defect. In particular, image processing
Pattern neighborhoods including neighborhoods of image-recognized regular patterns
When the area is set, the regular pattern is
Since there is no image, there is no need for image processing as it is.
Is binarized according to the defect with the lowest density,
A noise image of all types of defects with different reflection characteristics is displayed.
Therefore, it is possible to detect with high accuracy without leakage. Also,
In the vicinity of the pattern, the regular pattern recognized by the image is missing.
By distinguishing from the fall, high image recognition
It is possible to detect defects accurately. On the other hand, even if there is a defective hole or through hole that is overlooked by such image recognition, in the invention according to claim 2, the transmitted light to the inspected surface side of the disc of the illumination light is transmitted. By receiving the light, this can be easily and surely detected. Such a defect detection method can be similarly applied to discs of various reproduction methods, and further, only defects are detected at high speed and with high accuracy by receiving transmitted light and performing image processing and image recognition of a grayscale image by reflected light. Can be detected. Therefore, both equipment cost and inspection cost are reduced.

[0008]

[0009]

Further objects and features of the present invention will become apparent from the following detailed description and drawings. The above features of the present invention can be used alone or in combination in various combinations.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described together with examples thereof with reference to FIGS.

The disk inspection method of the present embodiment is an example in which various defects are detected by using a disk 1 as shown in FIG. 1 which is read and written due to a change in tissue as a light reflective disk to be inspected. However, the present invention is not limited to this, and it is possible to detect various defects having different reflection characteristics of various discs or holes and light-transmitting portions, and of course, it is possible to detect only one type of defect. Is.

Referring to the disc inspection apparatus according to the embodiment of the present invention shown in FIG. 1, the surface 1a to be inspected of the disc 1 is irradiated with the illumination light 3 from one side of the normal line 2 as well. The reflected light 4 from the surface 1a to be inspected is received on the side opposite to the normal line to obtain a grayscale image 5 of the surface 1a to be inspected as shown in FIG.
The transmitted light 6 from the disc 1 is received on the side opposite to
A defect of a hole or a transparent portion is detected by the transmitted light 6, a grayscale image 5 is image-processed, a noise image 7 of the defect is detected by image recognition, and a defect of the inspection surface 1a is detected.

As described above, by irradiating the light-reflective surface 1a with the illumination light 3 from one side of the normal line 2 and receiving the reflected light 4 on the side opposite to the normal line 2, A grayscale image 5 corresponding to the difference in the reflection condition of the surface 1a having the light reflectivity can be obtained. For this purpose, it is preferable that the incident angle of the illumination light 3 is about 10 ° to 80 ° with respect to the inspection surface 1a. When the angle is 10 ° or less, it is difficult to obtain a grayscale image depending on the difference in reflectance of the surface 1a to be inspected due to the reflected light 4. If it exceeds 80 °, interference of light and equipment occurs and it is not suitable for inspection.

The reflected light 4 has a mirror- symmetrical position with the illumination light 3 and the normal 2 as a boundary. Further, depending on the type of the disc, for example, the difference in material and thickness of the disc 1 or each layer constituting the disc 1, or the type of defect, a grayscale image 5 suitable for inspection corresponding to the difference in their reflection characteristics is obtained. Therefore, it is preferable to adjust the light amount of the illumination light 3. Depending on this adjustment or the state of light reception, it is possible to deviate from the angular range.

The grayscale image 5 shown in FIG. 3 includes various regular images such as the regular pattern 8 shown in FIG. 3 provided for reading and writing, and various noise images 7. As shown in the noise image 7 of the binarized detection image 5a shown in FIG. 5, only defects can be detected with high accuracy due to differences in density, patterns, and the like. On the other hand, even if there is a defective hole or through hole that is overlooked by this image recognition, the transmitted light 6 of the illumination light 3 to the surface opposite to the surface 1a to be inspected of the disk 1 is received. By doing so, this can be detected easily and surely. Such a defect detection method can be similarly applied to discs of various reproduction systems, and further, the reception of the transmitted light 6 and the
By the image processing and image recognition of the grayscale image 5 by the reflected light 4, only the defect can be detected with high accuracy at a high speed of about several seconds. Therefore, both equipment cost and inspection cost are reduced.

When the inspection surface 1a has the regular pattern 8 as described above, in the grayscale image 5, the regular pattern is subjected to image processing such as binarization to recognize the image and distinguish it from the defect. 8 is not detected as a defect. However, even with this, if the noise image 7 of the defect overlaps the regular pattern 8, it is difficult to detect it. Therefore, when the pattern neighborhood area 11 such as the grayscale image 5 shown in FIG. 4 including the neighborhood of the regular pattern 8 subjected to the image processing and image recognition is set, the regular pattern 8 does not exist outside the pattern neighborhood area 11. In the image processing state as it is, or by performing the binarization processing according to the defect having the lowest density, the noise image 7 can be obtained for all the various defects having different reflection characteristics and can be detected with high accuracy. it can. Further, in the pattern vicinity area 11, by distinguishing the recognized normal pattern 8 from the defect,
Similar to the outside, image recognition can detect defects with high accuracy.
In order to distinguish the regular pattern 8 from a defect, the corresponding pattern may be detected by pattern matching or the like, and the other pattern may be recognized as a noise image corresponding to the defect.

In order to achieve the above inspection method, the inspection apparatus of the present embodiment supports the disk 1 on the rotary disk 13 connected to the motor 12 as shown in FIG. While rotating, a grayscale image of the surface 1a to be inspected is captured. One example of the data is that the diameter of the disk 1 is 120 mm, the diameter of the central hole 1b is 15 mm, and the diameter of the turntable 13 is about 21 mm. The surface 1a to be inspected of the disk 1 is a range for reading and writing the disk 1, and has a diameter of 46 mm to 120 mm. Therefore, the hole 1b, which is one of the regular patterns at the center of the disk 1, is outside the range of the surface 1a to be inspected and does not enter the grayscale image 5. However, since the hole 1b is a normal image even in the grayscale image 5, it can be distinguished from the defect by the image processing and image recognition.

In order to capture the grayscale image 5 of the entire surface 1a to be inspected of the rotating disk 1, the illuminator 14 for irradiating the illumination light 3 illuminates the radial line of the surface 1a to be inspected of the disk 1 with the band-shaped illumination light 3. Then, when the band-shaped reflected light 4 is received by the light receiver 15, a gray image 5 of the surface 1a to be inspected can be obtained by one rotation of the disk 1. However, even if the grayscale image 5 is captured by sequentially scanning from one side to the other side of the inner and outer diameters by the point illumination, it can be achieved at a higher speed than the reproduction of the disk 1. The illuminator 14 has a light quantity adjusting unit 14a for adjusting the light quantity, and can be manually adjusted. A light receiver 17 is also provided for receiving the transmitted light 6 to the opposite surface side of the disk 1 in the range of the surface 1a to be inspected of the disk 1. The optical axes of the illuminator 14 and the light receiver 15 are mirror images of each other with respect to the normal line 2.
4 and the light receiver 17 are required to satisfy a predetermined positional relationship with each other so that their optical axes are on the same line. However, adjustment of the irradiation angle of the illumination light and light reception related thereto are necessary. It is supported to allow side angle adjustment. It is preferable that the angles can be adjusted by interlocking with each other while maintaining a predetermined angle and positional relationship.

The light reception data from the light receivers 15 and 17 is input to the image processing unit 20, where the judgment of the presence or absence of the detection of the transmitted light 6 and the image processing and image recognition of the grayscale image by the reflected light 4 are performed. Done. Specifically, the image processing unit 2
For 0, as shown in FIG. 2, first, the presence or absence of the transmitted light 6 is determined. As a result, if there is the transmitted light 6, the disc 1 can be immediately determined to be a defective product, and complicated image processing and image recognition operations can be omitted. If there is no transmitted light 6, the process proceeds to image defect detection by image processing and image recognition, and the image storage unit 22 stores the received light data of the reflected light 4 from the surface 1a to be inspected. As a result, when a predetermined grayscale image 5 for one disc 1 is accumulated, the pattern extracting unit 23 extracts the regular pattern 8. When the regular pattern 8 is extracted, the pattern neighborhood area 11 including the neighborhood of the regular pattern 8 extracted by the pattern neighborhood area defining unit 24 is defined. Then, the defect extraction section 25 within the pattern vicinity area and the defect extraction section 26 outside the pattern vicinity area perform the above-described defect extraction operation corresponding to each.

If any of these is defective, it is determined to be a defective disk, and if there is no defect, it is determined to be a good disk. If there is no regular pattern 8 in the pattern extraction unit 23,
If the noise image 7 is not detected by the pattern-free defect detection unit 27, it is detected as a defect and determined as a defective disk. If the noise image 7 is not detected, it is determined as a good disk without a defect.

As a result, the detection of the above-mentioned characteristic defects on one disk 1 is automatically and efficiently achieved in accordance with a predetermined program.

[0023]

Effects of the Invention According to the inspection method for a disk of the invention according to claim 1, the disk of the various playback method, the image processing and image recognition grayscale image by reflected light, only the high precision at high velocity defect Can be detected. Therefore, both equipment cost and inspection cost are reduced. Special
Even if there is a regular pattern on the surface to be inspected,
Is not detected as a normal pattern
Pattern outside the area near the pattern set for each pattern.
Eliminates the effects of regular patterns on the inside without
Then, image recognition can detect defects with high accuracy.
Wear.

A method for inspecting a disk according to the second aspect of the invention
According to the law, in the unlikely event that image recognition as described above
Even if there are defective holes or through holes that have been missed, the disc is inspected.
This can be done easily by receiving the transmitted light to the inspection side.
It can be reliably detected.

[0025]

[Brief description of drawings]

FIG. 1 is a schematic side view showing a disc inspection method and device according to an embodiment of the present invention.

2 is a flowchart showing an internal function and an example of processing operation of an image processing unit of the apparatus shown in FIG.

FIG. 3 is an example of a grayscale image captured from the surface to be inspected of the disc in the method and apparatus of FIG.

FIG. 4 is a setting example of a pattern vicinity area for a regular pattern in the grayscale image of FIG.

FIG. 5 is an example of a binarized detection image detected by setting the pattern vicinity area in FIG.

FIG. 6 is an example of a defect detection image by the binarization process performed by the present inventors.

[Explanation of symbols]

1 disc 1a Inspection surface 2 normal 3 illumination light 4 reflected light 5 gray image 6 transmitted light 7 noise image 8 Regular pattern 11 pattern neighborhood 13 turntable 14 Illuminator 14a Light intensity control unit 15, 17 Light receiver 20 Image processing unit 22 Image storage section 23 pattern extractor 24 pattern neighborhood definition section Defect extraction unit in the 25 pattern vicinity area 26 Defect extraction unit near pattern

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-281054 (JP, A) JP-A-6-242013 (JP, A) JP-A-4-97512 (JP, A) JP-A-7- 195383 (JP, A) Actual Kaihei 1-179245 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 21/84-21/958 G11B 7/26

Claims (3)

(57) [Claims] 1. A surface to be inspected of a light-reflecting disk is irradiated with illumination light from one side of a normal line, and light reflected from the surface to be inspected is received on the side opposite to the normal line. Te to obtain a gray image of the inspected surface, the grayscale image by image processing to set the pattern proximity including the vicinity of normal pattern image recognition, in the inside of the pattern proximity with the exception of the normal pattern image recognition , A method of inspecting a disc that performs an operation of detecting a noise image of a defect by image recognition without performing an operation of removing a regular pattern on the outside. 2. The disk inspection method according to claim 1 , wherein the surface of the disk opposite to the surface to be inspected receives the transmitted light from the disk, and the defect of the hole or the transparent portion is detected by the transmitted light. 3. The incident angle of illumination light is 1 with respect to the surface to be inspected.
The disk inspection method according to claim 1, wherein the disk angle is about 0 ° to 80 °.