JPH1194528A - Appearance inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost appearance inspection device wherein, with a to-be-inspected body not rotated, images of all end surfaces and outer peripheral surface are obtained while a time required for inspection is shortened. SOLUTION: An appearance inspection device 1 inspects the appearance of a to-be-inspected body 2 wherein, formed into a truncated cone, cylinder, and doughnut, etc., a flat end surface 3 and an outer peripheral surface 4 adjoining the end surface 3 are comprised, with a box-like member 6, a reflection member 7, and a camera 9, etc., provided. The box-like member 6 is provided with a lighting device 5 and a half mirror 15. The reflection member 7 comprises, as one body, a bottom part 17 on which the to-be-inspected body 2 is placed and a conical part 18 so extending from the edge of the bottom part 17 as its diameter gradually increases as advancing to the camera 9. An inside surface 18a of the conical part 18 is formed into a mirror surface. Relating to the reflection member 7, the image of the outer peripheral surface 4 is reflected on the inside surface 18a, introduced up to the camera 9. The camera 9 comprises a lens part 27 and an area sensor 8. The area sensor 8 images the entire pictures of the end surface 3 and the outer peripheral surface 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an appearance inspection apparatus for inspecting the appearance of an object to be inspected formed in a frusto-conical shape, a cylindrical shape, an annular shape, or the like.

[0002]

2. Description of the Related Art Conventionally, the appearance of an object to be inspected having an end face formed in any one of a frustoconical shape, a cylindrical shape, and an annular shape and having a flat surface and an outer peripheral surface adjacent to the end surface is described. For inspection, an appearance inspection device 51 as shown in FIG. 7 is used.

A visual inspection apparatus 51 illustrated in FIG. 7 is an apparatus for inspecting the external appearance of a test object 52 formed with the above-described end face 53 and outer peripheral face 54, and is opposed to the end face 53. First imaging means 55 and first light source 56 disposed
And the second imaging means 5 arranged opposite to the outer peripheral surface 54
7, a second light source 58, an image processing device 59, and the like.

[0004] The first imaging means 55 includes a first light source 5.
6 emits light and is reflected by the end face 53 so that an image of the end face 53 is obtained. Second
The imaging means 57 is adapted to obtain an image of the outer peripheral surface 54 by light emitted from the second light source 58 and reflected by the outer peripheral surface 54.

The image pickup means 55 and 57 each have a camera having a line sensor in which photoelectric conversion elements are arranged in a line (hereinafter referred to as a line sensor camera) or an area sensor in which photoelectric conversion elements are arranged in a matrix. Camera (hereinafter referred to as an area sensor camera).

When a line sensor camera is used, the visual inspection device 51 rotates the inspection object 52 along an arrow K shown in FIG. And the entire outer peripheral surface 54 are obtained.

When an area sensor camera is used, the visual inspection device 51 does not need to rotate the inspection object 52 when inspecting the end face 53. However, when inspecting the outer peripheral surface 54, the inspection object 52 is rotated along the arrow K in the drawing to obtain an image of the entire outer peripheral surface 54.

[0008] Regardless of whether the above-described line sensor camera or area sensor camera is used, the image processing device 59 adds a predetermined image to all the end faces 53 and the entire outer peripheral face 54 obtained as described above. The appearance of the inspection object 52 is inspected by performing processing and the like.

[0009]

As described above, the conventional visual inspection device 51 uses a rotary driving device or the like to obtain an image of the external appearance of the inspection object 52, in particular, an image of the entire outer peripheral surface 54. Therefore, it is necessary to rotate the test object 52 at least once. Further, it is necessary to provide an image pickup means 55 for obtaining an image of the entire end face 53 and an image pickup means 57 for obtaining an image of the entire outer peripheral surface 54, respectively.

As a result, the cost of the apparatus 51 itself tends to increase, and at least one rotation of the test object 52 increases the time required for the test. The number of test objects is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to obtain an image of the entire end face and the entire outer peripheral face of the test object without rotating the test object. It is an object of the present invention to provide a visual inspection apparatus capable of suppressing the cost of the apparatus itself and shortening the time required for the inspection.

[0012]

In order to solve the above-mentioned problems and to achieve the object, an appearance inspection apparatus according to the present invention is formed in any one of a frusto-conical shape, a cylindrical shape and an annular shape, and is flat. What is claimed is: 1. An apparatus for inspecting the appearance of an object to be inspected having a formed end surface and an outer peripheral surface adjacent to the end surface, comprising: an image pickup means for imaging an image of the external appearance of the object to be inspected; and an end surface of the object to be inspected. And an optical path changing unit that guides the image of the outer peripheral surface of the object to be inspected to the image pickup unit when the image of the end face of the object to be inspected is captured by the image capturing unit. It is characterized by that.

In the appearance inspection apparatus of the present invention, the end face of the object to be inspected is arranged opposite to the image pickup means, and when the image of the end face is picked up, the optical path changing means changes the image of the outer peripheral surface of the object to be inspected. Guide to imaging means. Therefore, it is possible to simultaneously obtain images of the entire end face and the entire outer peripheral face of the test object without rotating the test object.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Appearance inspection device 1
Is a device for inspecting the appearance of the test object 2 formed in any one of a frusto-conical shape, a cylindrical shape, and an annular shape. The test object 2 is formed to include a flat end surface 3 and an outer peripheral surface 4 adjacent to the end surface 3. Inspection object 2
Is designed to inspect the end face 3 and the outer peripheral face 4.

As the test object 2, for example, various bearings formed in a frusto-conical shape, a cylindrical shape, or an annular shape before, during or after assembling, and a track ring, a cylindrical roller, and a cone used for these bearings and the like. It is intended for rollers and the like.

The visual inspection apparatus 1 includes a box-shaped member 6 provided with an illumination device 5 and the like therein, a reflection member 7 as an optical path changing means on which the inspection object 2 is mounted, and a solid-state image sensor (CCD).
A camera 9 provided with an area sensor 8 as an image pickup means composed of a photoelectric conversion element such as the above, and an image processing device 10 are provided.

The box-shaped member 6 is formed in a box shape, and the surfaces 1 facing each other so that the camera 9 can obtain an image of the inspection object 2 placed on the reflection member 7.
Openings 13 and 14 are formed in 1 and 12.

The illumination device 5 and the half mirror 15 are provided inside the box-shaped member 6. Light emitted from the illumination device 5 is reflected by the half mirror 15,
The light is guided from one opening 14 to the reflection member 7 and the inspection object 2 placed on the reflection member 7.

In the illustrated example, a halogen lamp is used as the lighting device 5, but a device in which light-emitting diodes and the like are arranged in a matrix or a fluorescent lamp may be used. The half mirror 15 reflects the light emitted from the illumination device 5 and guides the light from one of the openings 14 to the reflection member 7, and transmits the light from the reflection member 7 to the camera 9.

As shown in FIG. 4, the reflecting member 7 is formed in a disk shape and is in contact with the bottom surface 16 of the device under test 2 to place the device under test 2 thereon, and an edge of the bottom portion 17. From the camera 9 to the camera 9 so as to gradually increase the opening diameter. Bottom 1
When the object 2 is placed on the object 7, an image of the end face 3 is guided to the camera 9.

The reflecting member 7 is made of, for example, metal, glass, or the like.
a, that is, the surface facing the outer peripheral surface 4 of the test object 2 to be placed is formed in a mirror-like shape by evaporating aluminum or the like.

With this configuration, when the inspection object 2 is placed on the bottom portion 17 with the end face 3 facing the camera 9, the outer peripheral surface of the inspection object 2 4 can be guided to the camera 9.

It is desirable that the image of the outer peripheral surface 4 of the inspection object 2 be formed as a virtual image G2 substantially parallel to the bottom surface 16 of the inspection object 2 as shown in FIG. When the virtual image G2 is formed substantially parallel to the bottom surface 16, the angle between the bottom surface 16 of the test object 2 and the outer peripheral surface 4 is set to Θ, and the extended surface 16c obtained by extending the bottom surface 16 in the outer peripheral direction is slid. Assuming that the angle between the portion 18 and the inner surface 18a is Θ2, the following Expression 1 is established.

Θ2 (degrees) = (180−Θ) / 2 Expression 1 If the relationship shown in Expression 1 is satisfied between Θ and Θ2, a virtual image of the outer peripheral surface 4 is obtained. G <b> 2 is formed parallel to the bottom surface 16, and the image on the outer peripheral surface 4 is guided to the camera 9. Then, as shown in FIG. 3, an image U1 of the end face 3 and an image G
1 are imaged substantially concentrically. As shown in FIG. 3, all the images U1 on the end face 3 and all the images G1 on the outer peripheral face 4 are displayed.
If and are within the range in which an image is formed on the area sensor 8 without overlapping each other, Θ and Θ2 do not have to satisfy the relationship of Equation 1 with each other.

The optical path changing means is provided in each of FIGS.
As shown in (1), the reflection members 19 and 20 may be formed in an annular shape having a triangular cross section. 5 and 6
The reflective members 19 and 20 shown in FIG. 1 show a case where the appearance of the end face 3a and the outer peripheral face 4a of the test object 2a formed in a cylindrical shape is inspected. FIGS. 5A and 6
(A) shows a perspective view of the reflection members 19 and 20, respectively, and FIG. 5 (B) and FIG. 6 (B) respectively show FIG.
7A and 7B are cross-sectional views taken along the line bb shown in FIG.

The reflection member 19 shown in FIG. 5 is designed to place the test object 2a in an inner space 21 formed in an annular shape, and the inner peripheral surface 22 forming the inner space 21 is It is formed along the direction toward the camera 9. Also,
The reflecting member 19 is formed such that its diameter gradually increases as its outer peripheral surface 23 moves toward the camera 9.
The space between the inner peripheral surface 22 and the outer peripheral surface 23 is a solid material.

The reflecting member 19 is made of a transparent material having a refractive index higher than that of the atmosphere, such as glass, and is formed smoothly by polishing the inner peripheral surface 22 and the outer peripheral surface 23. . The reflection member 19 includes the inspection object 2a.
The image of the outer peripheral surface 4a is reflected by the outer peripheral surface 23 due to a difference in refractive index from the atmosphere or the like, and is guided to the camera 9.

The extension surface 16 formed by extending the outer peripheral surface 23 and the bottom surface 16a of the device under test 2a in the outer peripheral direction.
b, and the angle Θ between the bottom surface 16a of the test object 2a and the outer peripheral surface 4a thereof preferably satisfy the relationship shown in the above-described expression 1, and the end face 3a of the test object 2a
If all the images U1 and all the images G1 on the outer peripheral surface 4a are imaged on the area sensor 8 without overlapping each other, the expression 1 need not be satisfied.

In the reflection member 20 shown in FIG. 6, the test object 2a is placed in an inner space 24 formed in an annular shape, and the inner peripheral surface 25 forming the inner space 24 is formed as described above. The diameter is gradually increased toward the camera 9. The outer peripheral surface 26 of the reflecting member 20 is formed along the direction toward the camera 9, and the space between the inner peripheral surface 25 and the outer peripheral surface 26 is a solid material.

The reflection member 20 is made of a transparent material having a refractive index higher than that of the atmosphere, such as glass, and is formed smoothly by polishing the surfaces such as the inner peripheral surface 25 and the outer peripheral surface 26. . The reflection member 20 includes the inspection object 2a.
The image of the outer peripheral surface 4a is reflected by the inner peripheral surface 25 due to a difference in the refractive index from the atmosphere or the like, and is guided to the camera 9. In this case, the reflecting member 20 is made of metal instead of glass, and has a tapered surface, that is, the inner peripheral surface 25.
May be made a mirror surface or made of glass, and aluminum or the like may be deposited on the tapered surface, that is, the inner peripheral surface 25.

An extended surface 16 formed by extending the inner peripheral surface 25 and the bottom surface 16a of the device under test 2a in the outer peripheral direction.
b, and the angle Θ between the bottom surface 16a of the test object 2a and the outer peripheral surface 4a thereof preferably satisfy the relationship shown in the above-described expression 1, and the end face 3a of the test object 2a
If all the images U1 and all the images G1 on the outer peripheral surface 4a are imaged on the area sensor 8 without overlapping each other, the expression 1 need not be satisfied.

The camera 9 includes a lens unit 27, the area sensor 8, and the like, and is connected to the image processing device 10. The lens unit 27 is, as shown in FIG.
And a focus adjustment mechanism for forming an image from the test object 2 a on the area sensor 8. In the illustrated example, the lens unit 27 focuses on an image of the end face 3 of the test object 2. The area sensor 8 is configured by arranging photoelectric conversion elements such as CCDs in a matrix.

The optical path length from the end surface 3 of the object 2 to the area sensor 8 and the optical path length from the outer peripheral surface 4 to the area sensor 8 have a slight difference depending on the size and shape of the object 2. ing.

For this reason, the above-mentioned slight difference in the optical path length causes a defocus ΔG described later. However, since this defocus ΔG is much smaller than a flaw or the like to be detected from the end face 3 and the outer peripheral face 4 of the inspection object 2, the lens unit 2
Even if 7 focuses on the image of end face 3, area sensor 8
Can secure the resolution required when the image processing apparatus 10 performs predetermined image processing by taking an image, and can inspect the appearance of the inspection object 2.

If the resolution required for the image processing apparatus 10 to perform predetermined image processing can be ensured, the lens unit 27 focuses on the image on the outer peripheral surface 4 of the test object 2. It may be.

In the case where the required resolution cannot be obtained by the above-described focusing method, the image of the end face 3 and the outer peripheral face 4 must be inspected. May be focused near the middle of the video. In this case, as compared with the case where one of the end face 3 and the outer peripheral face 4 is focused, the defocus of the image of the end face 3 and the defocus of the image of the outer peripheral face 4 are reduced, and the necessary resolution is secured. This makes it possible to detect more detailed flaws and the like.

Further, the box-shaped member 6 and the reflecting member 7 on which the object 2 is placed are integrally formed by using a separate driving device (not shown) without using the focus adjusting mechanism of the lens portion 27. It is movable in the direction of coming and going with respect to the camera 9, and focuses on either one of the image of the end surface 3 or the image of the outer peripheral surface 4 of the inspected object 2 or the middle of the image of the end surface 3 and the image of the outer peripheral surface 4. You may make it match.

Without providing the above-mentioned focus adjusting mechanism to the lens unit 27 of the camera 9, the lens unit 27 is previously provided with either the image of the end face 3 or the image of the outer peripheral surface 4 of the test object 2 or the image of the end face 3. The focus may be adjusted so as to be in the vicinity of an intermediate point between the image and the image on the outer peripheral surface 4, so that the focus does not need to be re-adjusted every time the inspection object 2 is inspected. In this case, the inspection speeds up, and the appearance of more inspected objects 2 can be inspected per unit time.

Further, when a finer resolution is required to detect a more detailed flaw or the like, the focus may be adjusted as shown below. The position where the image of the end face 3 is in focus and the position where the image of the outer peripheral surface 4 is in focus can be known in advance by the size and shape of the inspection object 2.

When the inspection object 2 and the reflection member 7 are set, first, the inspection is performed by focusing on one of the image of the end surface 3 and the image of the outer peripheral surface 4 of the inspection object 2. . After that, the inspection is performed while focusing on the other image.
As a device for adjusting the focal point, the above-described focus adjusting mechanism of the lens unit 27, a driving device that allows the box-shaped member 6 and the reflecting member 7 to move integrally in the direction of coming and going with respect to the camera 9 and the like are used. Is also good.

In this case, since the image of the end face 3 and the image of the outer peripheral surface 4 of the inspection object 2 are respectively focused, the resolution of the image picked up by the area sensor 8 becomes finer.
More detailed defects can be detected.

Further, by a control device (not shown) or the like,
The function of adjusting the focus, that is, a focus adjusting mechanism of the lens unit 27, a driving device that enables the box-shaped member 6 and the reflecting member 7 to move integrally in the direction of coming and going with respect to the camera 9 and the like may be automated.

Even when the focus adjustment mechanism and the driving device described above are automated, either one of the image of the end face 3 or the outer peripheral face 4 of the inspection object 2 or the image of the end face 3 and the image of the outer peripheral face 4 can be obtained. The image is focused near the middle or separately on the image of the end face 3 and the image of the outer peripheral face 4.

Further, a pinhole having a small opening diameter is provided in the lens portion 27 or the like to increase the amount of light radiated from the illumination device and to increase the depth of field, so that the image of the end face 3 of the inspection object 2 and the outer periphery thereof are formed. The image of the surface 4 may be focused simultaneously.

In this case, since the pinhole increases the depth of field and focuses on the image of the end face 3 and the image of the outer peripheral face 4 at the same time, it is possible to reliably detect more detailed flaws and the like.
The inspection speeds up, and more inspection objects 2 can be inspected per unit time.

The image processing apparatus 10 includes a known CPU, RO
An arithmetic unit having an M, a RAM, and the like. The arithmetic unit is connected to the camera 9, performs predetermined image processing on image data captured by the area sensor 8 of the camera 9, and And a function for inspecting the appearance of the outer peripheral surface 4 and the like.

According to the above-described configuration, when inspecting the appearance of the device under test 2, first, the device under test 2 and the reflection member 7 are set. Then, the lighting device 5 is operated. Then, the light emitted by the illumination device 5 is reflected by the half mirror 15 and guided to the test object 2 placed on the reflection member 7.

The image U1 of the end face 3 of the light guided to the test object 2 is represented by a two-dot chain line P shown in FIG.
The light passes through the half mirror 15 and forms an image on the area sensor 8. The illustrated example shows a case where the image of the end face 3 is focused. Then, as shown in FIG. 3, an image U1 of the end face 3 is captured substantially at the center of the area sensor 8.

On the other hand, the image of the outer peripheral surface 4 is reflected by the inner surface 18 a of the burring portion 18 of the reflecting member 7 by the light guided to the inspection object 2 described above. At this time, the angle Θ between the bottom surface 16 of the test object 2 and the outer peripheral surface 4 and the bottom surface 16
When the angle Θ2 formed between the extended surface 16c of the outer peripheral surface 4 and the inner surface 18a of the sliding portion 18 satisfies the relationship shown in the above equation 1, the virtual image G2 of the outer peripheral surface 4 is formed as shown in FIG. It is formed substantially parallel to the bottom surface 16 of the test object 2.

Then, the image of the outer peripheral surface 4 is transmitted through the half mirror 15 and guided to the area sensor 8 as shown by alternate long and short dash lines Q1 and Q2 shown in FIG. In the illustrated example, since the image on the end face 3 is focused, the image on the outer peripheral face 4 is changed to G3 shown in FIG.
As shown in the figure, an image is slightly formed from the area sensor 8 on the position of the inspection object 2.

In the area sensor 8, a dashed line Q
A defocus ΔG occurs between 1 and Q2. However, since the difference between the optical path lengths is small, even if the defocus ΔG occurs, the area sensor 8 can secure the required resolution and can reliably inspect the outer peripheral surface 4. Then, as shown in FIG. 3, the image G1 of the outer peripheral surface 4 is captured at a position around the area sensor 8 and substantially concentric with the image U1 of the end surface 3.

After that, the images U1 and G1 of the end face 3 and the outer peripheral face 4 of the test object 2 captured by the area sensor 8 are subjected to predetermined image processing in the image processing apparatus 10 as image data. Then, the appearance of the inspection object 2 is inspected.

According to the present embodiment, when the inspection object 2 is mounted on the reflecting member 7 with the end face 3 facing the camera 9 and is imaged, the reflecting member 7 slides the image of the outer peripheral surface 4. The light is reflected by the inner peripheral surface 18 a of the portion 18 and guided to the camera 9. Therefore, a single camera 9 can simultaneously obtain images of all of the end face 3 and all of the outer peripheral face 4 without rotating the test object 2, and a camera that captures an image of the end face 3. There is no need to provide a camera that captures images of the outer peripheral surface 4.

Accordingly, there is no need to use a rotary drive for rotating the device under test 2 and the number of cameras 9 can be reduced, so that the cost of the device 1 itself can be reduced. Further, since there is no need to rotate the test object 2 during the test, the time required for the test can be shortened, and more test objects 2 can be tested per unit time.

In this embodiment, the lighting device 5
The optical axis of the light radiated from the light source and reflected by the half mirror 15 to be guided to the test object 2, the optical axis of the image of the end face 3 of the test object 2, and the area sensor 8 by the reflection member 7
The optical axis of the image of the outer peripheral surface 4 guided to the optical sensor, the optical axis of the lens 28, and the center of the area sensor 8 are located substantially on the same line,
As shown in FIG. 2, one optical axis O is formed.

For this reason, the angle Θ between the bottom surface 16 of the inspected object 2 and the outer peripheral surface 4, the inner surface 18 a of the reflecting member 7 and the extended surface 1
When the angle Θ2 between the end face 3c and the end face 3c satisfies the relationship of the above equation 1, the images of the entire end face 3 and the entire outer peripheral face 4 are simultaneously captured by the area sensor 8.

Therefore, when the end face 3 is arranged opposite to the camera 9 and imaged, the image of the outer peripheral face 4 is reliably guided to the camera 9, and the appearance of the object 2 can be inspected without fail. It can be carried out.

[0058]

According to the present invention, when an image pickup means is arranged on an end face of an object to be inspected and an image of the end face is picked up,
The image of the outer peripheral surface of the test object can be guided to the imaging means by the optical path changing means. For this reason, without rotating the object to be inspected, images of the entire end surface and the entire outer peripheral surface of the object can be simultaneously obtained.

For this reason, there is no need for a rotary driving device for rotating the object to be inspected, and it is not necessary to provide an image pickup means for picking up an image of an end face and an image pickup means for picking up an outer peripheral surface, thereby reducing the number of image pickup means. be able to.

Therefore, the cost of the apparatus itself can be suppressed, and the time required for the inspection can be shortened because the object to be inspected does not need to be rotated at the time of the inspection. The test object can be inspected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a visual inspection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an optical path from an object to be inspected to an area sensor according to the embodiment.

FIG. 3 is an exemplary view showing an image of an inspection object captured by the area sensor according to the embodiment.

FIG. 4 is an exemplary sectional view of the reflecting member according to the embodiment;

FIG. 5 is a view showing a modification of the reflection member shown in FIG. 4;

FIG. 6 is a view showing a modification of the reflection member shown in FIG. 4;

FIG. 7 is an explanatory diagram showing a configuration of a conventional visual inspection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Appearance inspection apparatus 2 ... Inspection object 3 ... End surface 4 ... Outer peripheral surface 7 ... Reflecting member (optical path changing means) 8 ... Area sensor (imaging means) 19 ... Reflecting member (optical path changing means) 20 ... Reflecting member (optical path changing) means)

Claims (1)

[Claims] The present invention inspects the appearance of an object to be inspected having an end surface formed in any one of a frustoconical shape, a cylindrical shape, and an annular shape and having a flat surface and an outer peripheral surface adjacent to the end surface. An apparatus, wherein: an imaging unit that captures an image of an appearance of the inspection object; and the imaging unit is disposed relative to an end surface of the inspection object,
An optical path changing unit for guiding an image of an outer peripheral surface of the object to be inspected to the image capturing unit when the image of the end surface of the object is imaged by the imaging unit.