JP3442199B2 - Surface inspection equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection device for a sheet-like object, and more particularly, it can be used for surface inspection of a photoconductor belt of a copying machine, a printer or the like using an electrophotographic method. The present invention relates to the inspection device that enables hard copy evaluation based on inspection results.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional example of this type of surface inspection apparatus. A cylindrical body 10 for rotating a sheet-shaped inspection object 101, for example, a photosensitive belt used in a copying machine or the like.
2, 103 to stretch. The one cylindrical body 102 is rotationally driven in a clockwise direction at a constant speed by the drive means 131 and the drive belt 132, and accordingly, the device under test 101 moves at a constant speed in the direction of the arrow. At this time, the surface of the object 101 to be inspected, which is in close contact with the surface of the other cylindrical body 103, is illuminated by the illumination means 153, and the lens system 151 and the CCD 15 are irradiated.
An image of the surface of the object to be inspected is picked up by the image pickup means consisting of 2. The obtained image is stored in the frame memory, and the image is subjected to appropriate image processing to inspect whether there is a defect on the surface of the inspection object. However, in FIG. 9, the image processing system part is omitted.

Problems with this conventional surface inspection apparatus will be described with reference to FIG. In the figure, irregularities 111 are present on the surface of the inspection object 101. At this time, the unevenness 111 on the surface of the object to be inspected is observed as a change in brightness on the image obtained by imaging the surface of the object to be inspected. The cause of the unevenness 111 on the surface of the object to be inspected may be a defect in the object to be inspected such as a break of the object to be inspected. Also, when foreign matter is attached to the cylindrical body 103 that supports the inspection object, the unevenness 1 on the surface of the inspection object 101 is similarly similarly obtained.
11 occurs. As described above, in a system that determines the presence or absence of a defect by processing an image of the surface of an object to be inspected, since the image data are similar, it is determined that the foreign matter adhered to the cylindrical body is a defect, and the presence or absence of the defect is detected. Will be misjudged. It is considered that such foreign matter adheres to the surface of the cylindrical body with a low frequency of occurrence, but once the foreign matter adheres, it will seriously affect subsequent inspections. As a simple measure to solve this problem, imaging in a portion that is not in close contact with the cylindrical body can be considered. By this, it is considered that the influence of the surface of the cylindrical body can be avoided.
Other problems occur.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, the present invention makes imaging at a portion in close contact with a cylinder or the like a desirable method in surface inspection of the sheet-like object, and It is an object to directly solve the problem when foreign matter adheres to the body surface.

[0005]

[0006]

[Means for Solving the Problems ] To solve the above problems
The invention of the present application according to claim 1 includes a plurality of cylindrical body for supporting a sheet-like object to be inspected, drive means for rotating the cylindrical body, an illuminating means for illuminating the surface of the inspection object, An image pickup means for picking up an image of the surface of the object to be inspected, wherein the surface inspection apparatus for determining the presence or absence of a defect on the surface of the object to be inspected by processing the image data obtained by the image pickup means A surface inspection device is provided which is provided with a foreign matter detecting means for detecting the presence or absence of a foreign matter on the surface of the supporting cylindrical body, and by the detection by the foreign matter detecting means,
It is possible to distinguish a change due to a foreign substance existing in the image data.

The invention according to claim 2 of the present application is the above claim.
In the invention of 1, the detection of foreign matter on the surface of the cylindrical body that supports the inspection object and the detection time of defect detection on the surface of the inspection object are performed so that the detection of the foreign matter on the surface of the cylindrical body is completed first. The surface inspection apparatus is characterized by providing a time difference between the times, and by providing the time difference, it is possible to reliably detect only the surface defect of the sheet-shaped inspection object to be inspected.

The invention according to claim 3 of the present application is a sheet form.
A plurality of cylinders that support the object to be inspected and the cylinders are rotated.
Driving means and an illuminating hand that illuminates the surface of the object to be inspected
A step and imaging means for imaging the surface of the object to be inspected.
Process the image data obtained by the image pickup means.
Surface inspection to determine the presence or absence of defects on the surface of the object to be inspected with
In the device, attach to the surface of the cylindrical body that supports the object to be inspected.
Foreign matter removing means for removing foreign matter that adheres , foreign matter detecting means for detecting the presence or absence of foreign matter on the surface of the cylindrical body supporting the inspected body, and a cylinder for supporting the inspected body according to the detection result of the foreign matter detecting means. A surface inspection apparatus is provided which is provided with a control means for controlling the foreign matter removing means for removing foreign matter adhering to the body surface.
The foreign matter that has adhered is removed, and
No convexity is generated and false detection is made in the image data.
Rather, the foreign matter removing means, so that operation in accordance with the presence or absence of the foreign matter of the cylinder surface is controlled, thereby to reduce the degradation of the cylindrical surface.

The invention according to claim 4 of the present application is in the form of a sheet.
A plurality of cylinders that support the object to be inspected and the cylinders are rotated.
Driving means and an illuminating hand that illuminates the surface of the object to be inspected
A step and imaging means for imaging the surface of the object to be inspected.
Process the image data obtained by the image pickup means.
Surface inspection to determine the presence or absence of defects on the surface of the object to be inspected with
In the device, attach to the surface of the cylindrical body that supports the object to be inspected.
A foreign substance removing means for removing foreign matter deposited, means for determining the presence or absence of foreign matter of the cylindrical surface that supports the object to be inspected by processing the image data of the inspection object surface, the determination of the presence or absence of foreign matter According to the determination result by the means, the surface inspection apparatus is provided with a control means for controlling the foreign matter removing means for removing the foreign matter adhering to the surface of the cylindrical body supporting the inspected body, and removing the foreign matter. Attached to the cylindrical surface by means
The foreign matter that has adhered is removed, and
No convexity is generated and false detection is made in the image data.
Since the operation of the foreign matter removing means is controlled by detecting the presence or absence of foreign matter on the surface of the cylindrical body using the image data, there is no need for a new foreign matter detecting means on the surface of the cylindrical body. .

According to a fifth aspect of the present invention, a plurality of cylindrical bodies for supporting the sheet-shaped object to be inspected, a driving means for rotating the cylindrical bodies, and an illuminating means for illuminating the surface of the object to be inspected. An image pickup means for picking up an image of the surface of the object to be inspected, and processing the image data obtained by the image pickup means to determine the presence or absence of a defect on the surface of the object to be inspected. By processing the image data obtained by imaging the surface, a means for determining the presence or absence of foreign matter on the surface of the cylindrical body that supports the object to be inspected is provided. Since a means for determining the presence / absence of foreign matter on the surface is provided from the image data, there is no need for a new means for detecting the presence / absence of foreign matter on the surface of the cylindrical body, and means for detecting foreign matter on the surface of the cylindrical body for supporting the object to be inspected. The same function as if Current can, it is possible to simplify the apparatus.

According to a sixth aspect of the present invention, a plurality of cylindrical bodies for supporting the sheet-shaped object to be inspected, a driving means for rotating the cylindrical bodies, and an illuminating means for illuminating the surface of the object to be inspected. A surface inspecting apparatus for determining the presence or absence of a defect on the surface of the inspected object by processing the image data obtained by the imaging means, The surface inspection apparatus is characterized by being provided with means for reducing only a certain period of luminance change, and is provided with a means for reducing only a certain period of luminance change of the image data. It is possible to reduce the change in luminance that occurs at a cycle corresponding to the diameter of the cylindrical body that supports, and it is possible to easily detect only the defects on the surface of the inspection object.

The invention according to claim 7 of the present application is the above claim.
In the invention described in 6, the cycle in the means for reducing only a certain cycle of luminance change of the image data is
The surface inspection apparatus is characterized in that it is variable according to the diameter of the cylindrical body that supports the object to be inspected, and is provided with means for reducing only a certain periodic change in luminance of the image data, and the cycle Is variable according to the diameter of the cylinder that supports the object to be inspected, so the size of the cylinder that supports the object to be inspected, which changes according to the size of the object to be inspected, can be accommodated and highly versatile inspection is realized. it can.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an embodiment of the invention related to the invention of the present application, in which a foreign substance adhering to the surface of a cylindrical body for supporting an object to be inspected by a conventional surface inspection apparatus is removed. It is a figure which shows the case where the blade as a foreign material removal means to provide is provided. In the figure, 1 is an object to be inspected, 2 is a cylindrical body supporting the object to be inspected, 3 is another cylindrical body supporting the object to be inspected, 11
Is foreign matter attached to the surface of the cylindrical body, 31 is drive means, 3
2 is a drive belt, 51 is a lens system, 52 is CC
D, 53 are illuminations, 71 is a foreign matter removing means (blade)
Indicates. Here, the blade 71 removes the foreign matter on the surface of the cylindrical body by bringing its tip into contact with the surface of the cylindrical body and scraping off the foreign matter, and has the same length as the cylindrical body. In addition to this form, if the adhesive force of foreign matter attached to the surface of the cylindrical body is weak, even a device that blows air,
It is also possible to remove foreign matter. And, except that the blade 71 is provided, it operates in the same manner as the above-mentioned conventional example.

[0014] Figure 2, in the embodiment of the invention of the present application according to claim 1 or 2 wherein a diagram illustrating means for detecting the foreign substance of the cylinder surface, the inspection apparatus provided with a foreign matter removing means. In the figure, the same numerals as those in FIG. 1 indicate the same parts or elements. The operation of each part is almost the same as that shown in FIG. 1, and the driving device 31 and the driving belt 32 that transmits the driving force rotate the cylindrical body 2 supporting the inspection object at a constant speed, and the inspection object 1 While moving the lamp in the direction of the arrow at a constant speed, the illumination 53, the lens system 51, and the CCD 52
An image of the surface of the object to be inspected is taken by the image pickup means including. Then, in this embodiment, another cylindrical body 4 supporting the device under test 1 is added as a further component not shown in FIG. 1, and the portion surrounded by the device under test 1 is expanded, and the region under test is inspected there. Illumination means 56 and lens system 54 and CC for imaging the surface of the cylindrical body 3 on which the part for imaging the body surface acts.
An image pickup means including D55 is provided. By processing the image obtained by this image pickup means, the presence or absence of the foreign matter 11 on the surface of the cylindrical body can be inspected.
An image processing unit for determining the presence / absence of foreign matter on the surface of the cylinder is omitted. In this embodiment, as in the case of the defect inspection of the surface of the inspected object, the example in which the image processing by the output from the CCD is used for the surface inspection of the cylindrical body is shown. It is also possible to use a so-called flying spot method or the like in which the foreign matter is detected by irradiating the surface of the cylindrical body with the light and detecting a change in its reflection intensity. These methods are limited by the properties of the object to be inspected and are not particularly limited in the present invention. Further, FIG. 2 shows an embodiment of the invention of claim 2 . Here, it can be seen that the place where the surface of the cylinder is imaged is located before the place where the surface of the object to be inspected is picked up.Selecting this place causes a time difference at the detection time, and detects the foreign matter on the surface of the cylinder. Can be completed first, and the invention can be implemented by this mode.

FIG. 3 is a diagram showing the inspection apparatus provided with a control means for the foreign matter removing means in an embodiment of the invention according to claim 3 or 4 of the present application. In the figure, the same numerals as those in FIG. 2 indicate the same parts or elements, and there is no change in the operation. In this embodiment,
As shown in the figure, the cylindrical body 3 is provided with a means for detecting the foreign matter 11 on the surface of the cylindrical body 3 supporting the inspected body 1 and supporting the inspected body obtained by the image pickup means including the lens system 54 and the CCD 55. The image data 93 on the surface is sent to the image processing means 91, where the presence or absence of the foreign matter 11 on the surface of the cylinder is determined. The foreign substance presence / absence signal 94 is sent to the control unit 92 of the foreign substance removing means.
The drive signal 95 for driving the drive means 96 such as a motor for moving the blade 71 to the position of contact / non-contact with the surface of the cylindrical body is sent in response to the signal 94 indicating the presence / absence of foreign matter on the surface of the cylindrical body. Is output. This makes it possible to control the blade 71 to contact the surface of the cylinder only when the foreign matter 11 is present on the surface of the cylinder.

FIG. 4 shows the difference between a pseudo defect caused by adhesion of foreign matter on the surface of the cylindrical body and a genuine defect on the surface of the object to be inspected. In the figure, reference numeral 401 denotes an image obtained by imaging the surface of the object to be inspected by the surface inspection apparatus shown in FIG. 2 is a cylindrical body (diameter Φ) that supports the object to be inspected
Then, it is assumed that the foreign matter 11 is attached to the surface thereof. In the image 401 of the surface of the object to be inspected, there are four sites (412, 413, 41
4,415) exists. Among these, the luminance changes due to the foreign matter 11 on the surface of the cylindrical body are 412, 413, and 414, which appear in a cycle of the circumference L (= πΦ) of the cylindrical body. On the other hand, in the luminance change 415 caused by the real surface defect, at the position 4 corresponding to the period of the circumference L (= πΦ) of the cylindrical body.
No brightness change at 16 is seen. The presence or absence of foreign matter on the surface of the cylindrical body can be determined from the image of the surface of the object to be inspected by utilizing the property of having periodicity in the change in the brightness of the foreign matter on the surface of the cylindrical body. In the figure, the X axis corresponds to the axial direction of the cylindrical body, and the Y axis corresponds to the circumferential direction of the cylindrical body.

[0017] Figure 5 shows the aspect of an invention of the present application according to claim 5, wherein. In the figure, the reference numerals by the same numerals as in FIG. 1 indicate the same parts or elements, and there is no change in the operation. In this embodiment, an image signal 593 obtained by imaging the surface of the inspection object 1 is sent to an image processing device 591 for detecting the presence or absence of a defect on the surface of the inspection object. Therefore, the position data 594 in which the change in brightness considered to be a defect is detected is sent to the analyzing means 592. The position data analysis means 592 compares the position data already sent from the image processing device 591 with the newly sent position data to determine whether there is a periodicity of the circumference L (= πΦ) of the cylinder. Check. The image processing device 591 receives the signal 595 indicating the presence / absence of periodicity, and if there is periodicity, the luminance change is due to the foreign matter on the surfaces of the cylindrical bodies 2 and 3 and is not a defect on the surface of the inspection object 1. It is determined that there is a defect on the surface of the inspection object 1 only when there is no periodicity,
An OK / NG signal 596 is output. By doing so, even when it is difficult to provide a means for detecting the presence or absence of foreign matter on the surfaces of the cylindrical bodies 2 and 3 due to the size of the DUT 1 and the like, the foreign matter on the cylindrical body surfaces 2 and 3 can be provided. The inspection accuracy can be improved as in the case where the presence / absence detecting unit is provided.

Further, as means for improving the inspection accuracy in the invention according to claim 6 or 7 of the present application, a means for reducing only a change in luminance of a certain period of the image data obtained by imaging the surface of the inspection object. However, an embodiment of means for selectively reducing the signal of the period derived from the cylinder, that is, the period signal in the change in luminance caused by the adhesion of foreign matter on the surface of the cylinder will be described below. FIG. 6 (A) is a plot of predicted changes in luminance that are considered to be caused by the adhesion of foreign matter on the surface of the cylindrical body. The horizontal axis corresponds to the Y axis in FIG. 4,
The vertical axis represents luminance. This data is Fourier transformed and plotted (power spectrum) is shown in FIG. The horizontal axis represents the spatial frequency and the vertical axis represents the spatial frequency component. The specific spatial frequency component is large, and FIG. 6C shows the frequency component interpolated based on the surrounding values. An inverse Fourier transform of this is shown in FIG.
It can be seen that the periodic luminance change seen in (A) has disappeared. FIG. 7A and FIG. 7B each show a prediction and plot of a change in luminance due to a defect on the surface of the object to be inspected, and a power spectrum thereof. In the power spectrum, the specific spatial frequency component does not become strong, and by performing the inverse Fourier transform of the interpolated value based on the surrounding values, it becomes almost the same as the original signal as shown in FIG. 7 (C). The equivalent is obtained. Processing is performed in the process according to such a principle, and means for reducing only the luminance change of a constant cycle is implemented. FIG. 8 shows a flowchart of the above processing. Thus, by reducing the change in brightness caused by the foreign matter on the surface of the cylindrical body, it is possible to detect only the change in brightness caused by the defect on the surface of the object to be inspected, so that the inspection accuracy can be improved.

[0019]

The effect corresponding to the first aspect of the present invention: Since the detection means for detecting the presence / absence of foreign matter on the surface of the cylindrical body supporting the inspected body is provided, whether the luminance change on the surface of the inspected body caused by the foreign matter is detected. , It is possible to distinguish whether the luminance change is caused by a defect on the surface of the inspection object. Effect corresponding to claim 2 :
A defect is detected on the surface to be inspected after confirming the presence / absence of foreign matter on the surface of the cylinder by providing a time lag between the detection of foreign matter on the surface of the cylinder supporting the inspection object and the detection of defects on the surface of the inspection object. Therefore, only defects on the surface of the object to be inspected can be reliably detected.
Effect corresponding to claim 3 : Foreign matter removing means for removing foreign matter adhering to the surface of the cylindrical body supporting the inspected body, means for detecting the presence or absence of foreign matter on the surface of the cylindrical body supporting the inspected body, and the inspected body Since there is a control means for controlling the foreign matter removing means for removing the foreign matter adhering to the cylindrical body supporting the object to be inspected according to the presence or absence of the foreign matter on the surface of the cylindrical body supporting the Since it can be removed, it is possible to reduce the deterioration of the surface of the cylindrical body supporting the inspection object. Claim 4
Effect corresponding to: Foreign matter removing means for removing foreign matter adhering to the surface of the cylindrical body supporting the inspected object and the presence or absence of foreign matter on the surface of the cylindrical body supporting the inspected object are determined from image data of the surface of the inspected object. And a control means for controlling the foreign matter removing means for removing the foreign matter adhering to the cylindrical body supporting the inspected body according to the determination of the presence or absence of the foreign matter on the surface of the cylindrical body supporting the inspected body. The means for determining the presence / absence of foreign matter on the surface of the cylindrical body is simplified, and the foreign matter is removed only when it is determined that the foreign matter has adhered, so that the deterioration of the surface of the cylindrical body supporting the inspection object can be reduced. You can

Effect corresponding to claim 5 : Since there is a means for judging the presence or absence of foreign matter on the surface of the cylindrical body supporting the inspection object from the image obtained by imaging the surface of the inspection object, the inspection object is provided. No need for means for detecting the presence or absence of foreign matter on the surface of the cylindrical body that supports the object, and it is possible to realize the same function as when there is a means for detecting foreign matter on the surface of the cylindrical body that supports the object to be inspected, and to simplify the device. You can Effect corresponding to claim 6 : Since a means for reducing only a change in luminance of image data obtained by imaging the surface of the object to be inspected at a certain fixed period is provided, the diameter of the cylindrical body supporting the object to be inspected. It is possible to reduce the change in brightness that occurs in a cycle corresponding to, and it is possible to easily detect only the defects on the surface of the inspection object. Effect corresponding to claim 7 : A means for reducing only the luminance change of a certain period of the image data obtained by imaging the surface of the object to be inspected is provided, and the period of the cylindrical body supporting the object to be inspected. Since it is variable according to the diameter, it is possible to adapt to the size of the cylindrical body that supports the inspected object, which is changed according to the size of the inspected object, and it is possible to realize highly versatile inspection.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an invention related to the present invention .

FIG. 2 is a diagram showing an embodiment of the invention described in claim 1 or 2 .

FIG. 3 is a diagram showing an embodiment of the invention described in claim 3 or 4 .

FIG. 4 is an explanatory diagram showing a difference between a pseudo defect and a genuine defect.

FIG. 5 is a diagram showing an embodiment of the invention described in claim 5 ;

FIG. 6 is a diagram showing waveforms in image data conversion processing steps (A) to (D).

FIG. 7 is a diagram showing the principle of waveform conversion along steps (A) to (C).

FIG. 8 is a flowchart of a cycle change reduction process of image data.

FIG. 9 shows a conventional example of this type of surface inspection apparatus,
Shows a front view, and (B) shows a plan view.

FIG. 10 is a diagram showing a state in which foreign matter is attached to a cylinder in the conventional example of FIG.

[Explanation of symbols]

1, 2, 3, 4, 101, 102, 103 ... Cylindrical body, 1
1,111 ... Foreign matter adhered to the surface of the cylindrical body, 31,131
... Drive means, 32, 132 ... Drive belts, 51, 54,
151 ... Lens system, 52, 55, 152 ... CCD, 5
3, 56, 153 ... Illumination, 71 ... Foreign matter removing means (blade), 91 ... Image processing means, 92 ... Control section, 93, 59
3 ... Image data, 94 ... Foreign matter presence / absence signal, 95 ... Driving signal, 96 ... Driving means, 401 ... Image of surface of inspected object, 4
12 to 414 ... Luminance change derived from the foreign matter 11 on the surface of the cylindrical body,
415 ... Luminance change due to surface defect, 416 ... Position corresponding to cycle of circumference L (= πΦ) of cylindrical body, 591 ... Image processing device, 592 ... Analyzing means, 594 ... Position data,
595 ... Signal indicating presence / absence of periodicity, 596 ... OK / NG
Signal of.

Claims (7)

(57) [Claims] 1. A plurality of cylinders for supporting a sheet-shaped object to be inspected, driving means for rotating the cylinders, illumination means for illuminating the surface of the object to be inspected, and a surface of the object to be inspected. In a surface inspection apparatus that includes an imaging unit that captures an image, and determines the presence or absence of a defect on the surface of the inspection object by processing the image data obtained by the imaging unit, the surface of the cylindrical body that supports the inspection object A surface inspection apparatus comprising a foreign matter detecting means for detecting the presence or absence of a foreign matter. 2. Regarding the detection times of the foreign matter detection on the surface of the cylindrical body supporting the inspection object and the defect detection on the surface of the inspection object, both the detection times are set so that the detection of the foreign matter on the surface of the cylindrical body is completed first. The time difference is provided between the two.
1. The surface inspection device according to 1 . 3. A plurality of circles for supporting a sheet-shaped inspection object
Cylindrical body, drive means for rotating the cylindrical body, and the inspection target
Illuminating means for illuminating the surface of the body and the surface of the object to be inspected
And an image pickup means for picking up an image,
By processing the image data,
Supports the object to be inspected in the surface inspection device that determines the presence or absence
Foreign matter removal for removing foreign matter adhering to the surface of the cylindrical body
Removing means, a foreign substance detecting means for detecting the presence of foreign material of the cylindrical surface that supports the object to be inspected, the foreign matter adhering to the cylindrical surface that supports the object to be inspected in accordance with the detection result of the foreign matter detection means front surface inspecting apparatus characterized in that a control means for controlling said foreign substance removing means for 4. A plurality of circles supporting a sheet-shaped inspection object
Cylindrical body, drive means for rotating the cylindrical body, and the inspection target
Illuminating means for illuminating the surface of the body and the surface of the object to be inspected
And an image pickup means for picking up an image,
By processing the image data,
Supports the object to be inspected in the surface inspection device that determines the presence
Foreign matter removal for removing foreign matter adhering to the surface of the cylindrical body
And means, responsive to a determination result by the presence judging means of said means for determining the presence or absence of foreign matter of the cylindrical surface that supports the object to be inspected by processing the image data, the foreign matter of the inspection surface, front surface inspecting apparatus you characterized in that the provided control means for controlling said foreign substance removing means for removing foreign matter adhering to the cylindrical surface that supports the object to be inspected 5. A plurality of cylinders for supporting a sheet-shaped object to be inspected, a driving means for rotating the cylinders, an illumination means for illuminating the surface of the object to be inspected, and a surface of the object to be inspected. A surface inspection apparatus that includes an image capturing unit that captures an image, and processes image data obtained by the image capturing unit to determine the presence or absence of a defect on the surface of the inspected object. A surface inspection apparatus comprising means for processing the image data to determine the presence or absence of foreign matter on the surface of the cylindrical body supporting the inspection object. 6. A plurality of cylinders for supporting a sheet-shaped object to be inspected, a driving means for rotating the cylinders, an illumination means for illuminating the surface of the object to be inspected, and a surface of the object to be inspected. In a surface inspection apparatus that includes an image capturing unit that captures an image, and determines the presence or absence of a defect on the surface of the object to be inspected by processing the image data obtained by the image capturing unit, only a change in luminance of the image data in a certain fixed cycle is performed. A surface inspection apparatus comprising means for reducing 7. The cycle in the means for reducing only a certain periodic change in luminance of the image data is variable according to the diameter of the cylindrical body supporting the inspection object. 6. The surface inspection device according to 6 .