JP3369880B2 - Mirror surface recognition method for mirror-like inspected object - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror surface portion of a mirror-like inspected object such as a compact disc (hereinafter referred to as a CD) when inspecting a printed surface condition such as a character or a figure printed on the mirror surface portion. Regarding recognition method.

[0002]

2. Description of the Related Art Generally, in order to display recorded contents and the like on a CD, a manufacturer's name, music title, performer's name, etc. are printed on the mirror surface (hereinafter referred to as a print label). Then, conventionally, as a technique for inspecting whether or not the print state of the print label is defective, the print label is illuminated by an illuminating device, and the reflected light from the print label is input by an area camera to input an image. There is used a method of detecting a defect on a printing surface by performing various kinds of image processing and comparing with a reference image obtained from a printing label on which printing has been completed.

However, in this method, when the printing label has a mirror surface portion, if the mirror surface area is not correctly recognized, in addition to the defect generated on the printing surface, a rainbow or interference fringes may be formed on the mirror surface portion depending on the illumination device. May occur, a rainbow or interference fringes may be input as an image, and it may be determined as a defect despite the regular mirror surface state.

As a technique for recognizing the mirror surface range, there is, for example, an inspection device for recognizing the mirror surface portion using a special illumination device (flash).

[0005]

SUMMARY OF THE INVENTION The present invention provides an inexpensive and reliable mirror surface recognition method that accurately recognizes the mirror surface portion of a mirror-like object to be inspected and does not use a special lighting device such as a flash. The challenge is to provide.

The present invention is an inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting the object for inspection for defects.
A mirror surface inspection device for inspecting, which includes an illuminating device for illuminating the inspection object during imaging, an imaging device for imaging reflected light from the inspection object, and an image processing unit for processing the captured image. In, a reference inspection object having a mirror surface portion and a white portion is irradiated with an illumination device that adjusts the boundary light amount of halation generation in the mirror surface portion and the white portion, and reflected light from the reference inspection object is transmitted to an imaging device. It is characterized in that a boundary threshold value for recognizing the specular surface portion from the inspection object is set by performing image processing on the captured input image. The second embodiment of the present invention is an inspection device for inspecting an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting for defects in the object to be inspected. In the inspection device for a mirror-like inspection object having an illumination device, an imaging device for capturing the reflected light from the inspection object, and an image processing unit for processing the captured image, a reference object having a mirror surface portion and a white portion is provided. The inspection object is irradiated with the illumination device that is adjusted to the boundary light amount of the halation occurrence in the mirror surface part and the white part, the reflected light from the reference inspection object is subjected to image processing of the input image taken by the imaging device, The step of setting the boundary threshold value of halation occurrence on the mirror surface part and the non-mirror surface part, irradiating the inspection object with the illumination device, photographing the halation light reflected from the inspection object, performing image processing on the captured input image, and determining the boundary threshold value. Inspected by comparing with And judging the mirror surface portion and a non-mirror surface portion. Further, the lighting device is characterized by using a halogen light source. The third embodiment of the present invention is an inspection device for photographing an inspection object having a mirror surface portion and a non-mirror surface portion and inspecting the inspection object for defects, and illuminating the inspection object at the time of imaging. In the inspection device for a mirror-like inspection object having an illumination device, an imaging device for capturing the reflected light from the inspection object, and an image processing unit for processing the captured image, a reference object having a mirror surface portion and a white portion is provided. The inspection object is illuminated with an illumination device that adjusts the amount of boundary light that causes halation in the mirror surface portion and the white portion, and the reflected light from the inspection object for recognizing the reference is photographed with a monochrome imaging device. It is characterized in that the captured input image is input with a density value on a pixel-by-pixel basis, and based on this density, the mirror surface boundary threshold value is set from the inspection object. Further, the fourth embodiment of the present invention is an inspection device for photographing an inspection object having a mirror surface portion and a non-mirror surface portion and inspecting the inspection object for defects, and illuminating the inspection object at the time of imaging. A reference inspection object having a mirror surface portion and a white portion in a mirror surface inspection object inspection apparatus including an illuminating device, an imaging device for capturing reflected light from the inspection object, and an image processing unit for processing the captured image. The object is illuminated by the lighting device that has been adjusted to the boundary light amount of halation generation in the mirror surface part and the white part, the reflected light from the reference inspection object is photographed by the monochrome image pickup device, and the photographed input image is displayed. A step of inputting a density value for each pixel and setting a boundary threshold value for recognizing a mirror surface portion from the inspection object, and a halation light reflected from the inspection object by irradiating the inspection object with a lighting device and a monochrome image pickup device , And the density value of the captured input image in pixel units And force, by each pixel value is compared with the boundary threshold, characterized by determining the mirror surface portion and a non-mirror surface portion of the object to be inspected. In addition, the fifth embodiment of the present invention is an inspection apparatus for photographing an inspection object having a mirror surface portion and a non-mirror surface portion and inspecting the inspection object for defects, and illuminating the inspection object at the time of imaging. A reference inspection object having a mirror surface portion and a white portion in a mirror surface inspection object inspection apparatus including an illuminating device, an imaging device for capturing reflected light from the inspection object, and an image processing unit for processing the captured image. An object is illuminated with an illumination device that adjusts the amount of boundary light that causes halation between the mirror surface portion and the white portion, and the reflected light from the reference inspection object is photographed by a color image pickup device. Red image, green image, and blue image) are input as density values in pixel units for each of the three primary colors, the image values of each of the three primary colors are compared at the same pixel position, and the minimum pixel is selected from the three primary colors. Output the value and use the minimum pixel value of each output pixel position Set the minimum image, based on the image, and sets the boundary threshold value for recognizing the mirror portion from the object to be inspected. The sixth embodiment of the present invention is an inspection apparatus for photographing an inspection object having a mirror surface portion and a non-mirror surface portion and inspecting the inspection object for defects, and illuminating the inspection object at the time of imaging. A reference inspection object having a mirror surface portion and a white portion in a mirror surface inspection object inspection apparatus including an illuminating device, an imaging device for capturing reflected light from the inspection object, and an image processing unit for processing the captured image. An object is illuminated with an illumination device that adjusts the amount of boundary light that causes halation between the mirror surface portion and the white portion, and the reflected light from the reference inspection object is photographed by a color image pickup device. Red image, Green
Image, blue image) input density value for each of the three primary colors in pixel units, compare the image values of each of the three primary colors at the same pixel position, and output the minimum pixel value of the three primary colors. , A step of setting a minimum image using the minimum pixel value of each output pixel position, and setting a boundary threshold value for recognizing a mirror surface part from the inspection object based on this image, An object is irradiated, and the halation light reflected from the object to be inspected is photographed by a color image pickup device, and the photographed input image of each of the three primary colors (Red image, Green image, Blue image) is densified in pixel units for each of the three primary colors. A value is input, the pixel values of the images for each of the three primary colors are compared at the same pixel position, the minimum pixel value of the three primary colors is output, and the minimum pixel value of each output pixel position is used to generate the minimum image. Set the minimum pixel value and input the density value in pixel units. By each pixel value is compared with the boundary threshold value, and judging the mirror surface portion and a non-mirror surface portion of the object to be inspected.

The mirror surface extraction threshold value is obtained by irradiating a mirror surface-like inspection object having a mirror surface portion and a white portion with an illumination device that adjusts the boundary light amount of halation generation between the mirror surface portion and the white portion. The reflected light from the object to be inspected is subjected to image processing on an input image taken by the image pickup device, and is set as a boundary threshold value for halation occurrence in the mirror surface portion and the non-mirror surface portion.

The illumination device uses a light source such as a halogen light source which easily causes halation.

An inspection apparatus for photographing a mirror-like object to be inspected having a non-mirror surface portion and inspecting for defects in the mirror-like object to be inspected,
An image pickup device for photographing the specular object, an illumination device for illuminating the specular object at the time of photographing, an image pickup device for photographing reflected light from the specular object, and the photographed image. In a mirror surface inspection object inspection apparatus having an image processing unit for processing, the illumination device irradiates the mirror surface inspection object, and the halation light reflected from the mirror surface inspection object is input as an image by a monochrome imaging device. This is a method of discriminating a specular surface portion and a non-specular surface portion by inputting a density value for each pixel on a pixel-by-pixel basis and comparing with a threshold value for specular surface extraction inputted in advance.

The mirror surface extraction threshold value is obtained by irradiating a mirror surface inspection object having a mirror surface portion and a white portion with a lighting device that adjusts the boundary light amount of halation generation between the mirror surface portion and the white portion. The reflected light from the object to be inspected is input as an image with a monochrome imaging device. This input image is input with a density value on a pixel-by-pixel basis, and is used as a boundary threshold value for the occurrence of halation between the mirror surface portion and the non-mirror surface portion.

An inspection apparatus for photographing a mirror-like inspected object having a non-mirror-like portion and inspecting for defects in the mirror-like inspected object,
An image pickup device for photographing the specular object, an illumination device for illuminating the specular object at the time of photographing, an image pickup device for photographing reflected light from the specular object, and the photographed image. In a mirror surface inspection object inspection apparatus having an image processing unit for processing, the illumination device irradiates the mirror surface inspection object, and the halation light reflected from the mirror surface inspection object is input as an image by a color imaging device. This input image is converted into three primary colors (Re
The density value is input pixel by pixel for each of the d image, the Green image, and the Blue image, the pixel values of this gray image are compared at the same pixel position, the minimum pixel value is output among the three, and the mirror surface extraction determined in advance is performed. This is a method of determining a mirror surface portion and a non-mirror boundary surface portion by comparing with a threshold for use.

The mirror surface extraction threshold value is obtained by irradiating a specular object to be inspected having a specular surface portion and a white portion with an illuminating device that adjusts the boundary light amount of halation generation between the specular surface portion and the white portion to obtain a specular surface state. The reflected light from the object to be inspected is input as an image with a color image pickup device. This input image is input with a density value on a pixel-by-pixel basis, and is used as a boundary threshold for halation occurrence between the specular surface portion and the non-specular surface portion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a halogen illuminator is used in advance to adjust a light quantity of a reference CD print label having a mirror surface and a white ink portion so that the mirror surface portion is halated but the white ink portion is not halated. Then, the CCD image is taken, the input image is image-processed, and the mirror surface extraction threshold is set.

Next, halogen light is applied to the print label of the CD to be inspected having a mirror surface portion to cause halation on the mirror surface portion, and the reflected light is photographed by a CCD camera to subject the input image to image processing. In the previous section, the threshold value is compared with the specular portion extraction threshold value input in advance, and if the threshold value is equal to or greater than the threshold value, the specular portion is recognized.

When the CCD camera is for black and white, a halogen illuminating device is used in advance to halo the reference CD print label having a mirror surface and a white ink portion on the mirror surface portion but not on the white ink portion. The light amount is adjusted like this, the image is taken with a CCD camera for black and white, this input image is input with a density value in pixel units, and based on this density,
The boundary threshold of the mirror surface portion is set, the CD to be inspected is photographed with a CCD camera for black and white using a halogen illuminating device, and the portion where the pixel value of the input image is equal to or more than the threshold value for extracting the mirror surface portion is recognized as a mirror surface. .

If the CCD camera is for color, a halogen illuminator is used in advance to halo the reference CD print label having a mirror surface and a white ink portion on the mirror surface portion but not on the white ink portion. The amount of light is adjusted as described above, images are taken with a color CCD camera, a minimum value image for each pixel is created from this input RGB3 image, and the mirror surface boundary threshold value is set based on this image, and the CD to be inspected
Is photographed by a color CCD camera using a halogen illuminating device, the minimum value for each pixel is extracted from this input RGB3 image, and a minimum value image is created. It is recognized as a mirror surface portion.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a printed matter inspection apparatus installed in a multicolor printing machine such as a CD according to the present invention.
FIG. 2 shows a structural explanatory view of the present invention. The schematic configuration of the present invention will be described with reference to FIGS. 1 and 2. The CD print surface inspection apparatus 1 includes an image pickup apparatus 4 for photographing reflected light from a print label 3 of a CD 2, an illumination apparatus 5 for irradiating the print label 3, and Body frame 6, CD for fixing each device
It is composed of an inspection table 9 on which 2 is placed in a substantially central portion.
The image pickup device 4 includes a color CCD camera 7 and a monochrome CCD.
It is composed of a camera 8 and an image memory 14 for storing images photographed by respective CCD cameras, and an image processing device 15 for performing image processing.

The illumination device 5 includes a halogen illumination device 10 which emits halogen light, a surface illumination device 11 which converts the halogen light into parallel surface illumination, a half mirror 12 which is arranged at an angle of 45 ° with respect to the optical path, Fluorescent lighting device 13 (in the present embodiment, the type of defects on the printing surface (color spot defects are the fluorescent lighting device 1
3 is used, and the halogen lighting device 10 is used except for the color spot defect. ), The halogen lighting device 10 and the fluorescent lighting device 13 are used together. ).

Next, the operation of this embodiment will be described with reference to FIG. 2. The halogen light emitted from the halogen illuminating device 10 becomes parallel light in the surface illuminating device 11, and the half mirror 12 is used.
(Hereinafter referred to as “halogen surface illumination”), is reflected by the half mirror 12 at an angle of 45 °, and is irradiated onto the print label 3 (hereinafter referred to as “epi-illumination”). And
The halogen light reflected by the print label 3 passes through the half mirror 12 and is photographed by the color CCD camera 7 and the monochrome CCD camera 8. And each C
An image processing device 15 is provided after the CD camera, and C
The image captured by the CD camera is temporarily stored in the image memory 14 and processed by the image processing device 15.

FIGS. 3 and 4 are flowcharts for explaining the detection structure of the present invention.

This flowchart is divided into the case where the monochrome CCD camera 8 is used and the case where the color CCD camera 7 is used. Then, each is divided into a first stage for creating reference data and a second stage for actually carrying out an inspection.

FIG. 3 shows an example in which a monochrome CCD camera 8 is used, and the first stage (reference data preparation stage) (101 to 10).
5) illuminates the reference CD 2 (the print label has a mirror surface portion and a white ink portion) by using epi-illumination using a halogen surface illumination, and reflects light from the print label 3 on the black and white CCD camera 8 Shoot with (101). (The irradiation condition of the halogen surface illumination at the time of photographing adjusts the light quantity and the aperture of the camera lens so that the mirror surface part causes halation, but the white ink part does not cause halation.) Then, the black and white CCD camera 8 is used. The captured image is A / D converted by the image processing device 15 (102) and stored in the image memory 14 as an input image (103).
The density value of the input image stored in the image memory 14 is input in pixel units in the image processing device 15 (104).
Based on this density value, a mirror surface portion extraction threshold value for recognizing the mirror surface portion from the print label 3 is set (105).

In the second step (201 to 207), the CD2 to be inspected (the print label having the mirror surface portion and the printing portion such as characters and figures) is irradiated by using the epi-illumination by the halogen surface illumination, The halation light reflected from the print label 3 is photographed (201), and the A /
It is D-converted (202) and stored in the image memory 14 as an input image (256 gradation gray scale) (203). This input image is input to the image processing device 15 in density values pixel by pixel (204), and each pixel value is in the first stage (105).
It is compared whether or not it is "larger" than the mirror surface extraction threshold set in (205). If "YES", it is recognized as a mirror surface portion (the density value is set to "255") (20).
6). In the case of "NO", the print unit is recognized (the density value is set to "0") (207). Then, the determination results of the mirror surface portion and the printing portion are stored in the image memory 14 as a mirror surface extraction result image (208).

FIG. 4 shows an example using the color CCD camera 7 in the first stage (reference data preparation stage) (301 to 3).
05) illuminates the reference CD 2 (the print label has a mirror surface portion and a white ink portion) by using epi-illumination by halogen surface illumination, and reflects light from the print label 3 on the color CCD camera 7. (301). (The irradiation condition of the halogen surface illumination at the time of photographing is adjusted so that the specular surface portion causes halation but the white ink portion does not cause halation.) The color CCD camera 7 is adjusted. A / D conversion is performed on the images taken at (3021, 3022, 302
3), each three primary colors (Red image, Green image, Blu
The image (e image) is stored in the image memory 14 as an input image (256 grayscale grayscale image) (3031, 3).
032, 3033). The input image stored in the image memory 14 is input to the image processing device 15 for each of the three primary colors in density values in pixel units (3041, 3042, 304).
3) The smallest pixel value of the three is output (305).
A minimum image (256 grayscale grayscale image) is set using the minimum pixel value of each output pixel position, and a mirror surface extraction threshold for recognizing the mirror surface portion from the print label 3 is set based on this image. Yes (306).

In the second step (401 to 410), the CD2 to be inspected (the print label having the mirror surface portion and the printing portion such as characters and figures) is irradiated by using the epi-illumination by the halogen surface illumination, The halation light reflected from the print label 3 is photographed (401), A / D converted by the image processing device (4021, 4022, 4023), and each of the three primary colors (R
It is stored in the image memory 14 as input images (256 gradation grayscale grayscale images) of ed images, Green images and Blue images (4031, 4032, 4033).
This input image is processed by the image processing device 15 for each of the three primary colors.
Enter the density value in pixel units (4041, 4042, 404
3) The pixel values of the images for each of the three primary colors are compared at the same pixel position, and the minimum pixel value of the three is output (405). A minimum value image (256 gradation grayscale grayscale image) is set using the output minimum pixel value at each pixel position (4
06). Next, input the density value of the minimum value image pixel by pixel,
Whether or not each pixel value is “larger” than the mirror surface extraction threshold set in the first step (306) is compared (407).
If "YES", it is recognized as a mirror surface portion (for example, the density value is converted to "255") (408). "N
In the case of "O", it is recognized as a printing section (for example, the density value is converted to "0") (409). Then, the determination results of the mirror surface portion and the printing portion are stored in the image memory 14 as a mirror surface extraction result image (410).

By using this mirror surface extraction result image, the mirror surface of the print label can be accurately recognized. Since the mirror surface portion can be correctly recognized and the printing portion and the mirror surface portion are accurately separated, for example, when the fluorescent lighting device 13 is used, rainbow-colored interference fringes are generated on the mirror surface portion, and the imaging device A rainbow or interference fringes are reflected in the image captured in 1., an error occurs in the image, and there is no inconvenience that the defect is determined in spite of the normal mirror surface state.

Further, conventionally, a special lighting device (flash) is used separately from the halogen lighting device 10 and the fluorescent lighting device 13 in order to recognize the mirror surface. However, according to the present invention, the halogen lighting device 13 used at the time of inspection is used.
Accurate recognition of the mirror surface is possible only with this.

[0028]

The present invention is carried out in the form as described above, and has the following effects.

The mirror surface portion of the mirror-like object to be inspected can be accurately recognized, and error determination of defects does not occur when using fluorescent lighting.

Further, the mirror surface can be recognized only by the illumination device used at the time of inspection, and an inexpensive and reliable mirror surface recognition method can be provided without using a special light source such as a flash.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a main configuration used in a CD printing surface inspection apparatus in an embodiment of the present invention.

FIG. 2 is also a configuration explanatory diagram of a CD printing surface inspection device.

FIG. 3 is a block diagram illustrating a detection mechanism of the present invention. (When using a CCD camera for black and white)

FIG. 4 is a block diagram illustrating a detection mechanism of the present invention. (When using a CCD camera for color)

[Explanation of symbols]

2 Reference inspection object (reference CD) 3 Inspection object (print label) 8 Imaging device (black and white CCD camera) 7 Imaging device (color CCD camera) 10 Illumination device (halogen illumination device) 11 Illumination device (surface illumination device) ) 14 image processing unit (image memory) 15 image processing unit (image processing device) 1 mirror surface inspection device (CD printing surface inspection device) 10 halogen light source (halogen illumination device) 8 black and white image pickup device (black and white CCD) Camera) 7 Color imaging device (color CCD camera)

Claims (7)

(57) [Claims] 1. An inspection device for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting for defects in the object to be inspected, and an illumination device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Irradiate with the illumination device that is adjusted to the boundary light amount of halation in the white part and the white part, the reflected light from the reference inspection object is photographed by the image pickup device, and the image processing of the photographed input image is performed.
A method of recognizing a mirror-like object to be inspected, comprising setting a boundary threshold value for recognizing a mirror surface portion from the object to be inspected. 2. An inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting the object to be inspected for defects, and an illumination device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Illuminating with the illuminating device that adjusts the boundary light amount of halation generation in the white part and the white part, the reflected light from the reference inspection object is subjected to image processing of the input image taken by the imaging device, and the mirror surface part A step of setting a boundary threshold value for halation in a non-mirror surface portion, irradiating an object to be inspected with the illumination device, photographing halation light reflected from the object to be inspected, and image-processing the photographed input image to obtain the boundary threshold value. By comparing,
A method for recognizing a mirror surface of a mirror-like object to be inspected, comprising determining a mirror surface portion and a non-mirror surface portion of the object to be inspected. 3. The method for recognizing a mirror surface of a mirror-like inspection object according to claim 1, wherein the illumination device uses a halogen light source. 4. An inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting the object to be inspected for defects, and an illuminating device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Irradiation is performed by the illumination device that is adjusted to the boundary light amount of halation occurrence in the white and white parts, the reflected light from the reference inspection object is photographed by the monochrome image pickup device, and the photographed input image is pixel by pixel. A mirror surface recognition method for a specular object to be inspected, which comprises inputting a density value and setting a boundary threshold for recognizing the mirror surface portion from the object based on the density. 5. An inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting the object to be inspected for defects, and an illumination device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Irradiation is performed by the illumination device that is adjusted to the boundary light amount of halation occurrence in the white and white parts, the reflected light from the reference inspection object is photographed by the monochrome image pickup device, and the photographed input image is pixel by pixel. A step of inputting a density value and setting a boundary threshold value for recognizing a mirror surface portion from the inspection object, and irradiating the inspection object with the illumination device, and halation light reflected from the inspection object with a monochrome imaging device. Captured, and the captured input image is the density value in pixel units A mirror surface recognition method for a specular object to be inspected, which comprises discriminating between a specular surface portion and a non-mirror surface portion of the inspection object by inputting and comparing each pixel value with the boundary threshold value. 6. An inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting for defects in the object to be inspected, and an illuminating device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Each of the three primary colors (Red image) obtained by illuminating with the illuminating device that adjusts the amount of boundary light that causes halation in the white and white parts, and photographing the reflected light from the reference object to be inspected with a color imaging device. , Green image, Blue image), input density values for each of the three primary colors in pixel units, compare the image values of each of the three primary colors at the same pixel position, and determine the minimum pixel value of the three primary colors. Output, and use the minimum pixel value of each output pixel position A mirror surface recognition method for a specular object to be inspected, comprising setting a small image and setting a boundary threshold value for recognizing the specular surface portion from the object based on this image. 7. An inspection apparatus for photographing an object to be inspected having a mirror surface portion and a non-mirror surface portion and inspecting for defects in the object to be inspected, and an illuminating device for illuminating the object to be inspected at the time of image capturing. In a mirror surface inspection device having an imaging device for capturing reflected light from an inspection object and an image processing unit for processing the captured image, a reference inspection object having a mirror surface portion and a white portion is a mirror surface. Each of the three primary colors (Red image) obtained by illuminating with the illuminating device that adjusts the amount of boundary light that causes halation in the white and white parts, and photographing the reflected light from the reference object to be inspected with a color imaging device. , Green image, Blue image), input density values for each of the three primary colors in pixel units, compare the image values of each of the three primary colors at the same pixel position, and determine the minimum pixel value of the three primary colors. Output, and use the minimum pixel value of each output pixel position Setting a small image, based on this image, the step of setting a boundary threshold value for recognizing the mirror surface portion from the inspection object, and illuminating the inspection object with the illumination device, halation light reflected from the inspection object Each of the three primary colors (Red image, Green image,
An input image of a (Blue image) is input for each of the three primary colors on a pixel-by-pixel basis, and the image value of each of the three primary colors is compared at the same pixel position to output the minimum pixel value of the three primary colors. A minimum image is set using the minimum pixel value of each output pixel position, the minimum pixel value is input as a density value on a pixel-by-pixel basis, and each pixel value is compared with the boundary threshold value to obtain a mirror surface portion of the inspection object. And a non-mirror surface portion are determined, a mirror surface recognition method for a mirror-like inspected object.