JPH0642924A - Visual observation apparatus - Google Patents

Abstract

PURPOSE:To properly measure even a transparent and thin cylindrical body by making the outline of the body clearly represented on a screen. CONSTITUTION:The visual observation device is constituted of an illuminating device 3 and an imaging device 4 to observe an object 1 on a transparent supporting plate 2. The illuminating device 3 comprises a light source 6, a diffusion plate 5 and a slit, plate 7 with a slit mole 8. The illuminating device 3 is positioned so that the distance L1 to the object 1 is not smaller than the distance L2 between the object 1 and the imaging device 4. After the light from the light source 6 is diffused by the diffusion plate 5, the light is directed to the object 1 through the slit hole 8. The imaging device 4 images the object 1 from immediately above the object under the illumination of light. The image is binarized by an image processor (not shown) and the diameter of the object 1 is detected from the binary image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual observing device used for observing the outer shape of a cylinder, which is transparent and has a thin wall thickness, such as a glass tube or a synthetic resin tube.

[0002]

2. Description of the Related Art For example, when manufacturing a glass tube that is colorless and transparent and has a thin wall thickness, the diameter of the product may vary over an allowable value due to the temperature and viscosity of the raw materials. Therefore, it is necessary to measure the diameter of the product and determine whether or not the measured value is appropriate. There is also a method of using a tool such as a caliper for this kind of measurement, but since the thickness of the product is thin, the product may be damaged or deformed by contact with the tool.

Therefore, in order to perform this kind of measurement without contact,
A visual observation device having a configuration as shown in FIG. 4 has been proposed. This device example includes a lighting device 20 and an imaging device 21, and the imaging device 21 is electrically connected to an image processing device (not shown). The illumination device 20 includes a light source 22 such as a halogen lamp and a milky white diffusion plate 23, and the observation plate 1 is supported by the diffusion plate 23 and guided to an observation position. At the observation position, the image pickup device 21 is arranged toward the diffusion plate 23, and the observation target 1 is illuminated under the back illumination from the diffusion plate 23.
Image. The image signal from the image pickup device 21 is sent to the image processing device, subjected to binarization processing, and then the diameter of the observation target 1 is measured from the binary image.

FIGS. 5 (1) and 5 (2) show how diffused light (indicated by an arrow in the figure) from the diffusion plate 23 is applied to the observation target. The glass tubes having a thickness of about 0.5 mm and the glass tubes having a wall thickness of 0.1 mm or less in FIG.

[0005]

In the case of the observation object 1a shown in FIG. 5 (1), since the wall thickness is large, the transmitted light amount of diffused light is small especially at both sides where the optical path is long, and the outer shape of the glass tube is small. Appears clearly on the image. Therefore, a proper binary image can be obtained, and the diameter can be measured from the binary image. However, in the case of the observation target 1b shown in FIG. 5 (2), since the wall thickness is thin, the optical paths at both sides become short, the amount of transmitted light becomes large, and the diffused light from the vicinity position is in front of or both sides of the observation target 1b. Because it goes around the surface and reflects on the outer peripheral surface to shine,
The outer shape of the glass tube does not clearly appear on the image. Therefore, an appropriate binary image cannot be obtained and it is difficult to measure the diameter.

The present invention has been made in view of the above problem, and even if the observation target is a transparent and thin-walled cylindrical body, its outer shape clearly appears on the image and proper measurement processing is performed. An object is to provide a visual observation device that can be performed.

[0007]

The visual observation apparatus of the present invention is for observing the outer shape of a transparent and thin-walled cylindrical body as an observation target, and comprises a lighting device and an imaging device. It is a thing. The illuminating device is a diffuser placed behind the object to be observed with a predetermined distance, a light source placed behind the diffuser, and a slit hole placed near the diffuser to limit the projection area. It includes a slit plate provided. Further, the imaging device is positioned so as to face the diffusion plate with the observation target in the middle, and the distance between the observation target and the illumination device is set to a value equal to or greater than the distance between the imaging device and the observation target. ing.

[0008]

Since the distance between the observation object and the illumination device is sufficiently large and the projection area is limited by the slit plate, it is possible to prevent diffused light from wrapping around the front surface or both side surfaces of the observation object as much as possible, and to prevent the cylindrical shape. The reflection on the outer peripheral surface of the body is suppressed. Therefore, the outer shape of the tubular body clearly appears on the image, and the proper diameter can be measured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a visual observation device according to an embodiment of the present invention. The apparatus of the illustrated example uses a transparent and thin glass tube having a thin wall as an observation target 1. The observation target 1 is supported on a transparent support plate 2 and guided to an observation position. The diameter of the observation target 1 is measured by the visual observation device provided in.

The visual observation apparatus of the illustrated example comprises an illuminating device 3 and an image pickup device 4. An image signal from the image pickup device 4 is given to an image processing device (not shown) and binarized to obtain a binary image. Then, the diameter of the observation target 1 is measured.

The illuminating device 3 comprises a milky-white diffuser plate 5 in the form of a flat plate, a light source 6 such as a halogen lamp, and a slit plate 7 having a slit hole 8. The diffusion plate 5 is arranged at a predetermined distance L1 from the transparent support plate 2, and the light source 6 is positioned behind it to irradiate the diffusion plate 5 with light. The slit plate 7 is arranged immediately above the diffusion plate 5, and the slit plate 7 is positioned so that the slit hole 8 corresponds to the position of the light source 6. The slit plate 7 is for limiting the projection area of the diffused light from the diffuser plate 5, and it is desirable that the slit hole 8 is formed to have a diameter of about 3 to 5 times the diameter of the observation target 1. The slit plate 7 may be arranged on the lower surface of the diffusion plate 5.

An image pickup device 4 is arranged downwardly above the transparent support plate 2. The imaging device 4 faces the diffusion plate 5 with the observation target 1 in the middle, and images the observation target 1 under the back illumination from the diffusion plate 5 and outputs the image signal to the image processing device. The distance L2 between the observation target 1 and the imaging device 4 is determined according to the focal length of the objective lens of the imaging device 4, but the distance L1 between the illumination device 3 and the observation target 1 is
The lighting device 3 is positioned so that L1 ≧ L2.

In the visual observation device having the above structure, the observation target 1 is supported on the transparent support plate 2 and guided to the observation position. The light from the light source 6 is diffused by the diffusion plate 5, and the diffused light is emitted toward the observation target 1 through the slit holes 8 of the slit plate 7. Under this back illumination, the imaging device 4 images the observation target 1 from directly above, but as shown in FIG. 2, the distance between the observation target 1 and the diffusion plate 5 is sufficiently large and the projection area is defined by the slit plate 7. Because it is limited, diffused light is observed 1
It is prevented as much as possible from wrapping around the front surface or both side surfaces, and the reflection on the outer peripheral surface of the observation target 1 is suppressed. Therefore, the outer shape of the observation target 1 clearly appears on the image, and when this is binarized, a binary image 9 as shown in FIG. 3 is obtained.

In FIG. 3, the shaded portions 10 and 11 are observation objects 1.
A black pixel region representing both side portions (thickness portion) of the black pixel region, and an inner portion 12 thereof is a white pixel region representing a light transmitting portion of the observation target 1,
The outer portion 13 is a white pixel area representing the background portion.
The diameter D of the observation target 1 can be measured by the distance D between the shaded portions 10 and 11 of the binary image 9.

[0015]

As described above, according to the present invention, in order to observe the outer shape of a transparent thin cylindrical body as an observation target, a slit plate is arranged in the vicinity of the diffusion plate of the illuminating device, and Since the distance between the observation target and the illumination device is set to a value that is equal to or greater than the distance between the imaging device and the observation target, diffused light is prevented from wrapping around the front or side of the observation target as much as possible, and the outer circumference of the tubular body is reduced. The reflection on the surface is suppressed, the outer shape of the cylindrical body clearly appears on the image, and an appropriate diameter measurement process can be performed.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of a visual observation device according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing the principle of the device according to the present invention.

FIG. 3 is an explanatory diagram showing a binary image of a glass tube.

FIG. 4 is a front view showing a configuration example of a conventional visual observation device.

FIG. 5 is an explanatory diagram for explaining problems of the conventional example.

[Explanation of symbols]

 3 Illumination device 4 Imaging device 5 Diffusion plate 6 Light source 7 Slit plate 8 Slit hole

Claims (1)

[Claims] 1. A visual observation device for observing the outer shape of a cylinder, which is a transparent and thin-walled tubular body as an observation target, and comprises a lighting device and an imaging device, wherein the lighting device is the observation target. A diffuser placed behind the diffuser and a light source placed behind the diffuser,
And a slit plate provided with a slit hole for limiting the projection area, which is arranged in the vicinity of the diffusion plate, the imaging device is positioned facing the diffusion plate with the observation target in the middle, and the observation target The distance between the lighting device and the lighting device is set to a value equal to or greater than the distance between the imaging device and the observation target.