JPH06300534A - Spherical appearance inspection device - Google Patents

Abstract

PURPOSE:To recognize the three-dimensional form and defect of an inspection specimen indefinite in terms of a spherical shape like a pearl in a strict sense via the use of a single sheet of image, by photographing the image of a ring illuminant reflected on the specimen with a camera laid coaxially with the center axis of the ring illuminant. CONSTITUTION:Regarding the arrangement of ring illuminants 7a to 7c, the lowest ring is positioned lower than the equatorial surface of a pearl 8, and others are stacked in steps. When a camera 9 is positioned coaxially with the center axis of the ring illuminants 7a to 7c, ring images 11a to 11c come to be reflected on the surface of the pearl 8 at positions giving an exactly opposite positional relationship among the illuminants 7a to 7c, the surface of the pearl 8 and the camera 9. A change in the ring images 11a to 11c corresponds to the three-dimensional form of the pearl 8 by 1:1. Also, a defect itself, if existing, is a sudden change in the three-dimensional form and, therefore, observed as a sudden change in a ring image form as shown in a defect image 12. The three-dimensional form and defect of the pearl 8 can be thus concurrently photographed with the camera 9 by the use of the ring illuminants 7a and 7c as mentioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spherical appearance inspection apparatus for simultaneously inspecting defects and a three-dimensional shape of a part having a substantially spherical shape represented by pearls.

[0002]

2. Description of the Related Art FIG. 16 is a block diagram showing a conventional spherical appearance inspection apparatus disclosed in, for example, Japanese Patent Laid-Open No. 4-29042 and Japanese Patent Laid-Open No. 4-29043, and FIG. FIG. 18 is an external view of the inspection mask, and FIG. 19 is a view showing the inspection locus on the ball bearing. In the figure, 1 is a light source, 2 is a ball bearing which is a sample to be inspected, 3 is a camera, 4 is an epi-illumination device, 5 is a conveyance rotating unit, and 6 is a controller.

Next, the operation will be described. The illumination light emitted from the light source 1 illuminates the ball bearing 2 by the epi-illumination device 4, and the illumination image at this time is photographed by the camera 3 via the epi-illumination device 4. At this time, the area b at the top of the ball bearing 2 strongly reflects and saturates the light, and the area c becomes dark because the amount of light is insufficient. As a result, the inspectable area becomes the area a, and when the ball bearing 2 is rotated by the transport rotating unit 5, it becomes a belt-like area in which the area a is connected as shown in FIG. Further, the principle of the inspection is to detect the other changes with reference to the signal change in the area a obtained for the standard ball bearing.

[0004]

Since the conventional spherical appearance inspection device is constructed as described above, the shape of the ball bearing is treated as a known shape in the defect inspection, and the shape itself cannot be recognized. Met. In addition, it is impossible in principle to perform a defect inspection on a sphere whose shape is uncertain, such as a pearl. In addition, since the inspection area that can be performed by one image is small, in order to inspect the entire surface of the sphere, it is necessary to rotate the sphere as a whole and process many images, which requires a lot of time. was there.

The inventions of claims 1 to 3 are made to solve the above problems, and the three-dimensional shape and defects of the sample to be inspected, such as a pearl, in which the shape of the sphere is not strictly defined. It is an object of the present invention to obtain a sphere appearance inspection device capable of recognizing a single image.

Further, in addition to the above objects, an object of the present invention is to provide a spherical appearance inspection apparatus capable of inspecting an object to be inspected such as a pearl having a thread hole.

In addition to the above objects, it is another object of the present invention to provide a spherical appearance inspection apparatus capable of finding finer defects.

Further, in addition to the above objects, it is an object of the present invention to obtain a space-saving and highly sensitive spherical appearance inspection apparatus.

[0009]

According to another aspect of the present invention, there is provided a spherical appearance inspection apparatus, wherein an image of a ring light source reflected on a sample to be inspected is taken by a camera arranged coaxially with a central axis of the ring light source. A detection circuit for inputting an image detects the three-dimensional shape and defects of the sample to be inspected.

Further, in the spherical appearance inspection apparatus according to the invention of claim 2, the image of the ring light source projected on the sample to be inspected is converted into polar coordinate data by the polar coordinate conversion circuit, and the distribution shape of the polar coordinate data is converted by the unevenness MW determination circuit. The aspect ratio calculation and measurement circuit determines the aspect ratio of the polar coordinate data, and the shape determination circuit determines the shape of the sample to be inspected based on the above results.

Further, in the spherical appearance inspection apparatus according to the invention of claim 3, the high frequency component extracting circuit extracts only the high frequency component of the polar coordinate data, and the high frequency component area measuring circuit measures the area of the high frequency component to determine the number of high frequency components. The number of high frequency components is measured by the measuring circuit, and the defect rank of the inspected sample is judged by the defect rank judging circuit.

Further, in the spherical appearance inspection apparatus according to the invention of claim 4, the defect rank determination is performed when the pulse time width of the high frequency signal generated in the area indicated by the thread hole area signal generation circuit is a predetermined value. The circuit recognizes this as a signal indicating a thread hole and does not judge it as a defect.

Further, in the spherical appearance inspection apparatus according to the invention of claim 5, in the case where no defect is detected, in order to reveal the minute defect buried in the image of the ring light source,
The vertical fine movement table gives fine movement in the vertical direction to the sample to be inspected.

Further, in the spherical appearance inspection apparatus according to the invention of claim 6, in the case where no defect is detected, in order to reveal the minute defect buried in the image of the ring light source,
The vertical fine movement mechanism gives fine movement in the vertical direction to the ring light source group.

Further, in the spherical appearance inspection apparatus according to the invention of claim 7, in the case where no defect is detected, in order to reveal the minute defect buried in the image of the ring light source,
The vertical fine movement mechanism gives vertical fine movement to the camera.

Further, in the spherical appearance inspection apparatus according to the invention of claim 8, an image of the ring light source reflected on the sample to be inspected is taken by a camera arranged coaxially with the central axis of the wide ring light source, and the image is taken. The detection circuit for inputting the edges detects the three-dimensional shape and defects of the sample to be inspected.

Further, in the spherical appearance inspection apparatus according to the present invention, the ring projected on the sample to be inspected by the camera arranged coaxially with the central axis of the single ring light source which is vertically moved by the vertically moving mechanism. The image of the light source is taken multiple times.

[0018]

The spherical appearance inspection apparatus according to the invention of claim 1 is
By photographing the image of the ring light source reflected on the sample to be inspected by the camera arranged coaxially with the central axis of the ring light source, and detecting the three-dimensional shape and defects of the sample to be inspected by the detection circuit which inputs the image, Appearance inspection of the inspected sample is possible.

Further, in the spherical appearance inspection apparatus according to the invention of claim 2, the image of the ring light source reflected on the sample to be inspected is converted into polar coordinate data by the polar coordinate conversion circuit, and the distribution shape of the polar coordinate data is judged by the unevenness MW judgment circuit. The aspect ratio calculation measurement circuit measures the aspect ratio of the polar coordinate data, and the shape determination circuit determines the shape of the sample to be inspected based on the above results, giving an appropriate appearance according to the various shapes of the sample to be inspected. Can be inspected.

In the spherical appearance inspection apparatus according to the invention of claim 3, the high frequency component extracting circuit extracts only the high frequency component of the polar coordinate data, and the high frequency component area measuring circuit measures the area of the high frequency component to measure the number of high frequency components. The number of high frequency components can be measured by the circuit, and the defect rank of the inspected sample can be judged by the defect rank judgment circuit.

Further, in the spherical appearance inspection apparatus according to the invention of claim 4, the defect rank determination circuit is provided when the pulse time width of the high frequency signal generated in the area indicated by the thread hole area signal generation circuit is a predetermined value. This prevents the thread hole from being mistaken for a defect.

Further, in the spherical appearance inspection apparatus according to the invention of claim 5, when no defect is detected, vertical fine movement is applied to the sample to be inspected by the vertical fine movement table so as to be buried in the image of the ring light source. It is possible to reveal existing micro defects.

Further, in the spherical appearance inspection apparatus according to the invention of claim 6, when no defect is detected, fine movement in the vertical direction is given to the ring light source group by the vertical fine movement mechanism, so that it is buried in the image of the ring light source. It is possible to reveal existing micro defects.

Further, in the spherical appearance inspection apparatus according to the invention of claim 7, when no defect is detected, the vertical fine movement mechanism gives fine vertical movement to the camera.
Small defects buried in the image of the ring light source can be revealed.

Further, in the spherical appearance inspection apparatus according to the invention of claim 8, an image of the ring light source reflected on the sample to be inspected is taken by a camera arranged coaxially with the central axis of the wide ring light source, and the image edge thereof is taken. By detecting the three-dimensional shape and the defect of the sample to be inspected by the detection circuit for inputting, the shape data of twice the number of ring light sources can be obtained.

Further, in the spherical appearance inspection apparatus according to the invention of claim 9, a ring light source projected on a sample to be inspected by a camera arranged coaxially with a central axis of a single ring light source which is vertically moved by a vertically moving mechanism. By taking a plurality of images of, the visual inspection of the sample to be inspected can be performed with a single ring light source.

[0027]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a spherical appearance inspection apparatus according to the invention of claim 1, FIG. 2 is a sectional view for explaining an image forming action, and FIG. 3 is a view showing a ring image actually photographed.
In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. Reference numerals 7a to 7c are ring light sources, 8 is a pearl (sample to be inspected), 9 is a camera, 10 is a detection circuit into which image data of the camera 9 is input, 11a to 11
c is a ring image on the pearl 8, and 12 is a defect image on the defect of the pearl 8.

Next, the operation will be described. Ring light source 7
The bottom rings of a to 7c are placed below the equatorial plane of the pearl 8, and the rest are stacked in a totem pole manner in multiple stages. At this time, the scene viewed from the camera 9 arranged coaxially with the central axes of the ring light sources 7a to 7c shows that the ring light sources 7a to 7c, the surface of the pearl 8 and the 3 of the camera 9 as shown in FIG.
The ring images 11a to 1 at the position where the person has a positional relationship of regular reflection.
1c is reflected on the surface of the pearl 8, and ring images 11a to 11c as shown in FIG. 3 are obtained.

At this time, if the pearl 8 is an ideal sphere, the ring images 11a to 11c are true circles and are concentric.
On the other hand, if it is an elliptical sphere such as a rugby ball, the ring images 11a to 11 are also ellipses whose major axes extend in the same direction, and if they are irregular three-dimensional shapes, they will be irregular shapes that are cut off. Is apparent due to the geometrical reason of specular reflection, so that the change in the ring images 11a to 11c corresponds to the three-dimensional shape of the pearl 8 in a one-to-one manner. If the defect itself is considered to be an abrupt change in the three-dimensional shape with respect to the defect, it is observed as an abrupt change in the ring image shape as shown in the defect image 12 in FIG.

From these things, the multi-stage ring light source 7a
By using ~ 7c, the three-dimensional shape of the pearl 8 and the defect are simultaneously photographed by the camera 9 as a change in the ring shape. The detection circuit 10 detects the three-dimensional shape of the pearl 8 and the defect from the ring images 11a to 11c captured by the camera 9. Needless to say, by arranging a part of the multi-stage ring light sources 7a to 7c below the equatorial plane of the pearl 8, it is possible to inspect the entire hemisphere with one image.

Example 2. FIG. 4 is a block diagram showing an embodiment of the spherical appearance inspection apparatus according to the invention of claim 2, and FIG. 5 is a diagram showing processing data obtained by polar coordinate conversion. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. Reference numeral 13 is a polar coordinate conversion circuit, 14 is a concave-convex MW determination circuit, 15 is an aspect ratio calculation / measurement circuit, and 16 is a shape determination circuit. In addition, FIGS. 5A to 5D are examples of data converted into polar coordinates by the polar coordinate conversion circuit 13.

Next, the operation will be described. The pearl 8 is a natural or cultured product, and its shape is roughly a sphere, but it is not a true sphere. In addition, since the pearl 8 is actually processed by making a hole in the necklace, the shape of the pearl 8 when attached to the necklace becomes a problem in the appearance inspection. For this reason,
Even if it is an elliptical sphere, it is necessary to determine that it has a different shape depending on whether the major axis is the direction of the thread hole. Here, it is assumed that the pearl 8 is placed by the alignment mechanism so that the thread hole is horizontal and parallel to the horizontal axis of the camera 9.

The ring image photographed by the camera 9 in such a state is subjected to polar coordinate conversion by the polar coordinate conversion circuit 13 with the center of the image as the origin and the horizontal axis on the right side of the origin as the rotation angle origin (0 degree). A typical example of this polar coordinate conversion data is shown in FIG. When the pearl 8 is photographed with the rugby ball placed horizontally, polar coordinate conversion data is shown in FIG.
As shown in (b), the concave or alphabetical W
It becomes the shape. On the other hand, when the pearl 8 is photographed with the rugby ball placed vertically, the polar coordinate data is as shown in FIG.
As shown in (d), the convex shape or alphabetical letter M
It becomes the shape.

Experimental results confirm that almost all pearls 8 exhibit data in either of these forms.
In addition, pearls that were judged to be spherical by human eyes 8
Has these polar coordinate data shapes, and the aspect ratio of the amplitude of the unevenness MW (the ratio of the 90 degree value and the 270 degree value of the polar coordinate data to the same 0 degree and the sum of the 180 degree values) is close to 1. It was also made clear.

Accordingly, in the visual inspection of the pearl 8, first, the ring image is polar coordinate converted by the polar coordinate conversion circuit 13 with the image center as the origin and the horizontal axis on the right side of the origin as the rotation angle origin, and the basic shape is recognized by the unevenness MW determination circuit 14. . Next, the aspect ratio calculation / measurement circuit 15 measures the aspect ratio of the polar coordinate data output from the polar coordinate conversion circuit 13. The data of the unevenness MW determination circuit 14 and the aspect ratio calculation / measurement circuit 15 are input to the shape determination circuit 16, and those having an aspect ratio close to 1 are regarded as true spheres, and other shapes are shaped according to the shape of the unevenness MW and the aspect ratio. By making the determination, it is possible to determine a three-dimensional shape that is similar to a visual work.

In this work, in principle, the shape can be judged from one image, but if necessary, the pearl 8 is appropriately rotated with the hole as the center of the rotation axis to obtain another projection cross-section data, It is also possible to make a comprehensive judgment.

Example 3. FIG. 6 is a block diagram showing an embodiment of the spherical appearance inspection apparatus according to the invention of claim 3, and FIG. 7 is an explanatory view showing the concept of signal processing. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. Reference numeral 17 is a high frequency component extraction circuit for extracting only high frequency component extraction data 19 from the polar coordinate conversion data 18 output from the polar coordinate conversion circuit 13, 20 is a high frequency component area measurement circuit, 21 is a high frequency component number measurement circuit, and 22 is a defect rank determination circuit. , 23 is a high frequency component, and 24 is an area between the high frequency component and the baseline.

Next, the operation will be described. For convenience of explanation, it is assumed here that the polar coordinate conversion data 18 has a concave shape as shown in FIG. When a defect occurs on the ring image data, a local change is superimposed on the polar coordinate conversion data 18 as shown by the high frequency component 23 in FIG. The fact that this high-frequency component 23 is local data means that the pearl 8 has a defect.
It is easy to understand if it is considered that the shape change occurs locally in the.

The high frequency component extraction circuit 1 to which the polar coordinate conversion data 18 including the local high frequency component 23 is input.
In 7, the processing is performed so that only the high frequency component 23 is extracted as the high frequency component extraction data 19. The high frequency component extraction data 19 extracted here is input to the high frequency component area measuring circuit 20, and the area 24 of the high frequency component generated between the high frequency component and the baseline is measured, and at the same time, is input to the high frequency component number measuring circuit 21. , The number of high frequency components 23 (corresponding to the number of defects on the pearl 8) is measured. Here, the area 24 of the high frequency component has a correlation with the degree of surface irregularity generated by the defect.

Next, the measured result is input to the defect rank judgment circuit 22 and the defect rank is judged by the size of the area 24 of the high frequency component. Further, the information on the number of defects obtained by the high frequency component number measuring circuit 21 is simultaneously referred to, and it is determined whether the defect is a dense defect or a large defect, and the number of defects is small even in the same area. In this case, it is determined that there is a major defect, and the rank is increased. As a result, the determination result of the defect rank is close to the sensation of the defect visually perceived by human eyes, and the defect inspection close to the visual inspection becomes possible.

Example 4. FIG. 8 is a block diagram showing an embodiment of the spherical appearance inspection apparatus according to the invention of claim 4, and FIG. 9 is an explanatory view showing the concept of signal processing. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. Reference numeral 25 is a high-frequency component pulse time width measuring circuit for measuring the time width of the high-frequency component pulse, 26 is a thread hole area signal generation circuit showing an area where a thread hole may occur, 27 is a defect rank determination circuit, and 28 is a thread. A hole corresponding signal, 29 is a thread hole region, and 30 is a thread hole region extraction signal.

Next, the operation will be described. For convenience of description, it is assumed here that the pearl 8 is placed by the alignment mechanism so that the thread holes are substantially horizontal, and that the detection of defects is performed by the algorithm of the third embodiment.

In the ring image photographed in such a state, the polar coordinate conversion circuit 13 sets the center of the image as the origin and the horizontal axis (thread hole axis) on the right side of the origin is the rotation angle origin, that is, the mouth of the thread hole is 0 ° and 180 °. Undergo some polar transformation. In such a state, the thread hole is usually invisible when viewed from directly above, and does not adversely affect the inspection. However, since the shape of the pearl 8 is not a true sphere, the condition that the thread hole is placed horizontally is not satisfied depending on the alignment state, and the hole mouth may be visible when viewed from directly above. In this case, the hole mouth is optically equivalent to one concave defect, and the polar coordinate conversion data 18 is greatly distorted as shown by the thread hole corresponding signal 28 in FIG.

A device configuration for preventing this malfunction is shown in FIG. In FIG. 8, the polar coordinate conversion circuit 13 outputs the polar coordinate conversion data 18 to the high frequency component extraction circuit 17, and the high frequency component extraction circuit 17 extracts the high frequency and outputs the high frequency component extraction data 19 to the high frequency component area measuring circuit 20 and the high frequency component number measurement. Output to the circuit 21 and the high frequency component pulse time width measuring circuit 25. High frequency component area measurement circuit 2
0, the high frequency component number measuring circuit 21, and the high frequency component pulse time width measuring circuit 25 show the measurement results as the defect rank judging circuit 27.
Entered in.

The defect rank judging circuit 27 compares the size information of the thread hole which is known in advance with the time width measured by the high frequency component pulse time width measuring circuit 25 to pick up the thread hole-like data and The thread hole area extraction signal 30 output from the thread hole area signal generation circuit 26 indicating the area in which the thread hole is likely to occur, and when the both match, that is, the thread hole area 29 in which the thread hole may occur
In addition, when one thread hole corresponding signal 28 whose size is considered to be a thread hole is generated, the same defect is recognized as a thread hole and is not determined as a defect. As a result, it is possible to extract only the defect without causing a malfunction even if the pearls 8 are aligned with some error.

Example 5. FIG. 10 is a block diagram showing an embodiment of a sphere appearance inspection apparatus according to the invention of claim 5, and FIG. 11 is a diagram showing an actually photographed ring image. In the figure,
Since the same reference numerals as those of the conventional one indicate the same or corresponding portions, the description thereof will be omitted. Reference numeral 31 is a vertical fine movement table for moving the pearl 8 up and down.

Next, the operation will be described. In this embodiment, when an extremely small defect that is buried in the ring image is detected, the pearl 8 is moved in the vertical direction and the optical specular reflection condition is changed to separate the defect from the ring image. It is designed to be detected.

As in the first embodiment shown in FIG. 1, the ring light source 7 is used.
The bottom rings of a to 7c are placed below the equatorial plane of the pearl 8, and the rest are laminated in a totem pole manner. At this time, the scene viewed from the camera 9 is the ring light source 7a-
7c, the surface of the pearl 8 and the three members of the camera 9 form a ring image on the surface of the pearl 8 in a positional relationship of regular reflection.
a to 11c are obtained.

At this time, if there is a defect on the pearl 8, the ring images 11a to 11c are locally deformed corresponding to the irregularities of the defect, but the defect is small and the position of the defect is the regular reflection point of the ring. If it is located at, the ring may not be deformed. Therefore, when inspecting such a minute defect, first, the ring is imaged in a normal state and the inspection is performed. At this time, as shown in FIG.
When the local deformations of a to 11c are not observed, the vertical fine movement table 31 is operated to move the pearl 8 slightly up or down, and the image is taken again. At this time, the pearl 8 and the ring light source 7a
Due to a slight change in the positional relationship of 7c, the ring images 11a to 11c on the pearl 8 according to the geometric conditions of FIG.
The place where is occurring also shows a slight movement, and the ring image 11
The defects buried in a to 11c move to the vicinity of the ring, and ring images 11a to 11c are generated as shown in FIG.
Since c is locally deformed, it can be recognized as a defect, and as a result, the defect resolution can be improved. Needless to say, the pearl 8 having no defect can be determined if no defect exists even if the position of the pearl 8 is moved.

Example 6. FIG. 12 is a block diagram showing an embodiment of the spherical appearance inspection apparatus according to the invention of claim 6. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. 32 is a ring light source 7a-7c
It is a vertical fine movement mechanism that moves.

Next, the operation will be described. In this embodiment, when an extremely small defect that is buried in the ring image is detected, the pearl 8 is moved in the vertical direction and the optical specular reflection condition is changed to separate the defect from the ring image. It is designed to be detected.

Similar to the fifth embodiment shown in FIG. 10, in the ring light sources 7a to 7c, the lowermost ring is placed below the equatorial plane of the pearl 8 and the rest are laminated in a totem pole type. At this time, the scene viewed from the camera 9 is the ring light source 7a-
7c, the surface of the pearl 8 and the three members of the camera 9 form a ring image on the surface of the pearl 8 in a positional relationship of regular reflection.
a to 11c are obtained. At this time, if there is a defect on the pearl 8, the ring images 11a to 11c are locally deformed corresponding to the irregularities of the defect, but the defect is small and the position of the defect is located at the regular reflection point of the ring. If it is, the ring may not be deformed.

As a countermeasure against this, in the fifth embodiment, the position of the pearl 8 is finely moved up and down by the vertical fine movement table 31 and the positional relationship between the ring light sources 7a to 7c and the pearl 8 is slightly shifted to reveal the defect. However, since the shape of the pearl 8 is not a true sphere, there are many cases in which the pearl 8 is accompanied by rotational shake due to a disturbance such as vibration when it is moved up and down, and a case in which reliable movement is difficult occurs. Therefore, when inspecting such a minute defect, the ring is first imaged and inspected in a normal state.

At this time, if local deformation of the ring is not observed as shown in FIG. 11 (a), the vertical fine movement mechanism 32 as shown in FIG. 12 is operated to activate the ring light sources 7a-7c.
Is moved slightly up or down and the image is taken again. At this time,
As the positional relationship between the pearl 8 and the ring light sources 7a to 7c is slightly changed, the place where the ring images 11a to 11c are generated on the pearl 8 also slightly moves according to the geometric condition of FIG. The defect buried in the images 11a to 11c moves to the vicinity of the ring, and the ring images 11a to 11c are locally deformed as shown in FIG. Therefore, the defect resolution can be improved. Needless to say, the pearl 8 having no defect can be determined if no defect exists even if the position of the pearl 8 is moved as in the fifth embodiment.

Example 7. In Example 6, the vertical fine movement mechanism 32 finely moved the positions of the ring light sources 7a to 7c up and down to slightly shift the positional relationship between the ring light sources 7a to 7c and the pearl 8 to reveal the minute defects. Similarly to this, in the seventh embodiment, the same effect as that of the sixth embodiment can be obtained by moving the camera 9 in the vertical direction by the fine vertical movement mechanism to change the optical specular reflection condition.

Example 8. In the above embodiments, one ring image has been obtained by one ring light source.
Therefore, the ring light sources are stacked in multiple stages corresponding to the resolution required for inspection, but the number of stacked layers is limited by the space. The eighth embodiment collects ring image data twice as many as the number of light sources by using both edge information of one ring light source to improve resolution.

FIG. 13 is a block diagram showing an embodiment of a sphere appearance inspection apparatus according to the invention of claim 8, FIG. 14 is a photographed ring image, and FIG. 15 is an example of polar coordinate data. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted.

Next, the operation will be described. In FIG. 13, the ring light sources 7a to 7c are light sources wider than those in FIG. In the image obtained by such a wide ring light source, the reflected ring images 11a to 11c are also wide. The data obtained by converting the ring image data into polar coordinates becomes similarly wide data as shown in the ring images 11a to 11c in FIG. 15. However, if the edge component is extracted, for example, three rings are formed as shown in FIG. On the other hand, the number is doubled to six, and the spatial resolution is improved twice.

Therefore, the ring images 11a to 11 shown in FIG.
By selecting the ring light source width such that the width of the ring portion of c and the width of the gap between the rings are the same, it is possible to equivalently obtain effective polar coordinate data twice as many as the number of rings. Since it is easier to increase the width of the light source with less space restrictions than to increase the number of rings, it is possible to improve the spatial resolution of defects by utilizing the limited space space.

Example 9. Although a plurality of ring light sources have been used in the above embodiments, one ring light source may be moved up and down by the up-and-down moving mechanism to take a plurality of images of the ring light source on the sample to be inspected by the camera. Due to
The visual inspection of the sample to be inspected can be performed with a single ring light source as in the above embodiments.

[0061]

As described above, according to the first aspect of the invention, the spherical appearance inspection apparatus captures an image of the ring light source reflected on the sample to be inspected by the camera arranged coaxially with the central axis of the ring light source. Since the detection circuit that inputs the image is configured to detect the three-dimensional shape and defects of the sample to be inspected, the three-dimensional shape and defects of the sample to be inspected whose sphere shape is strictly indefinite like a pearl are detected. This has the effect of providing a spherical appearance inspection device that can be recognized by a single image.

According to the second aspect of the present invention, in the spherical appearance inspection apparatus, the image of the ring light source on the sample to be inspected is converted into polar coordinate data by the polar coordinate conversion circuit, and the distribution shape of the polar coordinate data is calculated by the unevenness MW determination circuit. The aspect ratio calculation measurement circuit measures the aspect ratio of polar coordinate data, and the shape determination circuit determines the shape of the sample to be inspected based on the above results. Accordingly, there is an effect that a spherical appearance inspection device capable of performing an appropriate appearance inspection can be obtained.

According to the third aspect of the present invention, in the spherical appearance inspection apparatus, the high frequency component extraction circuit extracts only the high frequency component of the polar coordinate data, and the high frequency component area measurement circuit measures the area of the high frequency component. Since the number of high-frequency components is measured by the number measurement circuit and the defect rank determination circuit determines the defect rank of the sample to be inspected, a spherical appearance inspection apparatus capable of performing defect inspection close to human visual inspection can be obtained. effective.

Further, according to the invention of claim 4, in the spherical appearance inspection apparatus, when the pulse time width of the high frequency signal generated in the area indicated by the thread hole area signal generating circuit is a predetermined value, the defect rank is determined. Since the thread hole is not mistakenly recognized as a defect by the judgment circuit, there is an effect that it is possible to obtain a spherical appearance inspection apparatus capable of inspecting an object to be inspected such as a pearl having a thread hole processed.

According to the fifth aspect of the present invention, the sphere appearance inspection apparatus is constructed so that the fine movement in the vertical direction is applied to the sample to be inspected by the vertical fine movement table when no defect is detected. There is an effect that it is possible to obtain a sphere appearance inspection device capable of discovering minute defects buried in the image.

According to the sixth aspect of the present invention, the spherical appearance inspection apparatus is configured to give the ring light source group fine movement in the vertical direction by the vertical fine movement mechanism when no defect is detected. There is an effect that it is possible to obtain a spherical appearance inspection apparatus capable of finding a minute defect buried in an image of a ring light source without causing a position shift of an object.

Further, according to the invention of claim 7, the sphere appearance inspection device is constituted so that the fine movement in the vertical direction is given to the camera by the vertical fine movement mechanism when no defect is detected. Similar to the invention, there is an effect that it is possible to obtain a spherical appearance inspection apparatus capable of finding a microscopic defect buried in an image of a ring light source without causing a positional deviation of an object to be inspected.

According to the eighth aspect of the present invention, the spherical appearance inspection apparatus captures an image of the ring light source reflected on the sample to be inspected by the camera arranged coaxially with the center axis of the wide ring light source, Since it is configured to detect the three-dimensional shape and defects of the sample to be inspected by the detection circuit that inputs the image edge, shape data that is twice the number of ring light sources can be obtained, and space-saving and highly sensitive sphere appearance inspection The effect is that a device can be obtained.

Further, according to the invention of claim 9, the spherical appearance inspection apparatus is mounted on the sample to be inspected by a camera arranged coaxially with the central axis of a single ring light source which is vertically moved by a vertically moving mechanism. There is an effect that a space-saving spherical appearance inspection apparatus capable of performing an appearance inspection of a sample to be inspected with a single ring light source can be obtained by taking a plurality of images of the reflected ring light source.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a spherical appearance inspection apparatus according to the invention of claim 1.

FIG. 2 is a diagram illustrating an image forming action.

FIG. 3 is a diagram showing an actually captured ring image.

FIG. 4 is a configuration diagram showing an embodiment of a sphere appearance inspection device according to the invention of claim 2;

FIG. 5 is a diagram showing processed data obtained by polar coordinate conversion.

FIG. 6 is a configuration diagram showing an embodiment of a sphere appearance inspection device according to the invention of claim 3;

FIG. 7 is an explanatory diagram showing the concept of signal processing.

FIG. 8 is a configuration diagram showing an embodiment of a sphere appearance inspection device according to the invention of claim 4;

FIG. 9 is an explanatory diagram showing the concept of signal processing.

FIG. 10 is a configuration diagram showing an embodiment of a sphere appearance inspection apparatus according to the invention of claim 5;

FIG. 11 is a diagram showing an actually captured ring image.

FIG. 12 is a configuration diagram showing an embodiment of a spherical appearance inspection apparatus according to the invention of claim 6;

FIG. 13 is a configuration diagram showing an embodiment of a spherical appearance inspection apparatus according to the invention of claim 8;

FIG. 14 is a diagram showing an actually photographed ring image.

FIG. 15 is a configuration diagram showing an example of polar coordinate data.

FIG. 16 is a configuration diagram showing a sphere appearance inspection device according to a conventional invention.

FIG. 17 is a configuration diagram showing an optical system section of a spherical appearance inspection apparatus according to a conventional invention.

FIG. 18 is an external view of an inspection mask.

FIG. 19 is a diagram showing an inspection locus on a ball bearing.

[Explanation of symbols]

 7a ring light source 7b ring light source 7c ring light source 8 pearl (sample to be inspected) 9 camera 10 detection circuit 13 polar coordinate conversion circuit 14 unevenness MW determination circuit 15 aspect ratio calculation measurement circuit 16 shape determination circuit 17 high frequency component extraction circuit 20 high frequency component area measurement Circuit 21 High frequency component number measurement circuit 22, 27 Defect rank determination circuit 25 High frequency component pulse time width measurement circuit 26 Thread hole area signal generation circuit 31 Vertical fine movement table 32 Vertical fine movement mechanism

[Procedure amendment]

[Submission date] July 16, 1993

[Procedure Amendment 1]

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[Figure 1]

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[Figure 4]

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[Figure 6]

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[Figure 8]

[Procedure Amendment 5]

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[Name of item to be corrected] Fig. 10

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[Figure 10]

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[Name of item to be corrected] Fig. 12

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[Fig. 12]

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

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[Fig. 13]

Claims (9)

[Claims] 1. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the central axis of the ring light source and that captures an image of the ring light source that is reflected on the sample to be inspected. A detection circuit for detecting the three-dimensional shape of the sample to be inspected from the shape change of the image of the ring light source taken by the camera, and detecting a defect of the sample to be inspected from the rapid shape change of the image of the ring light source; Sphere appearance inspection device equipped with. 2. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the center axis of the ring light source and that captures an image of the ring light source that is reflected on the sample to be inspected. A polar coordinate conversion circuit for converting the image data of the ring light source photographed by the camera into polar coordinate data, a concavo-convex MW determination circuit for determining whether the distribution shape of the polar coordinate data is the concavo-convex MW, and the polar coordinate data. Of the aspect ratio calculation and measurement circuit for measuring the aspect ratio, and a shape determination circuit that receives the outputs of the unevenness MW determination circuit and the aspect ratio calculation and measurement circuit to determine the shape of the sample to be inspected. 3. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the center axis of the ring light source and that captures an image of the ring light source that is reflected on the sample to be inspected. A polar coordinate conversion circuit for converting the image data of the ring light source taken by the camera into polar coordinate data, a high frequency component extraction circuit for extracting only the high frequency component of the polar coordinate data, and a high frequency component area measurement for measuring the area of the high frequency component. A sphere provided with a circuit, a high frequency component number measuring circuit for measuring the number of the high frequency components, and a defect rank determination circuit for determining the defect rank of the inspected sample from the area and number of the measured high frequency components. Appearance inspection device. 4. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the central axis of the ring light source and that captures an image of the ring light source that appears on the sample to be inspected. A polar coordinate conversion circuit for converting the image data of the ring light source taken by the camera into polar coordinate data, a high frequency component extraction circuit for extracting only the high frequency component of the polar coordinate data, and a high frequency component area measurement for measuring the area of the high frequency component. A circuit, a high-frequency component number measuring circuit for measuring the number of high-frequency components, a high-frequency component pulse time width measuring circuit for measuring the pulse time width of the high-frequency component, and a signal indicating a region where a thread hole may exist And a yarn hole area signal generating circuit that determines the defect rank of the inspected sample from the area and number of the measured high frequency components. , If the pulse time width of the high frequency signal generated in the area indicated by the thread hole area signal generation circuit is a predetermined value, it is recognized as a signal indicating the thread hole and is not judged as a defect rank. A sphere appearance inspection device including a determination circuit. 5. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the center axis of the ring light source and that captures an image of the ring light source reflected on the sample to be inspected. A detection circuit for detecting the three-dimensional shape of the sample to be inspected from the shape change of the image of the ring light source taken by the camera, and detecting a defect of the sample to be inspected from the rapid shape change of the image of the ring light source; In a spherical appearance inspection apparatus equipped with, in order to reveal a minute defect buried in the image of the ring light source when no defect is detected, a vertical fine movement table for giving a vertical fine movement to the inspected sample. A spherical appearance inspection device comprising: 6. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the central axis of the ring light source and that captures an image of the ring light source that is reflected on the sample to be inspected. A detection circuit for detecting the three-dimensional shape of the sample to be inspected from the shape change of the image of the ring light source taken by the camera, and detecting a defect of the sample to be inspected from the rapid shape change of the image of the ring light source; In a sphere appearance inspection apparatus including: a vertical fine movement mechanism that applies fine movement in the vertical direction to the ring light source group in order to reveal a minute defect buried in the image of the ring light source when no defect is detected. A spherical appearance inspection device comprising: 7. A ring light source group that surrounds the sample to be inspected and is stacked in multiple stages, and a camera that is arranged coaxially with the center axis of the ring light source and that captures an image of the ring light source that is reflected on the sample to be inspected. A detection circuit for detecting the three-dimensional shape of the sample to be inspected from the shape change of the image of the ring light source taken by the camera, and detecting a defect of the sample to be inspected from the rapid shape change of the image of the ring light source; In a sphere appearance inspection apparatus including, in order to reveal a minute defect buried in the image of the ring light source when no defect is detected, a vertical fine movement mechanism for vertically moving the camera is provided. A spherical appearance inspection device characterized in that 8. A wide ring light source group that surrounds the sample to be inspected and is stacked in multiple layers, and is arranged coaxially with the central axis of the ring light source, and captures an image of the ring light source reflected on the sample to be inspected. The three-dimensional shape of the sample to be inspected is detected from the shape change of the edge of the image of the ring light source captured by the camera and the camera, and the defect of the sample to be inspected is detected from the abrupt shape change of the image edge of the ring light source. A sphere appearance inspection device including a detection circuit for detecting the. 9. The ring light source group is configured by one ring light source, and a vertical movement mechanism for moving the ring light source up and down is provided, according to any one of claims 1 to 8. Sphere appearance inspection device.