JPH0138568Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compensation device for compensating for transmission loss of the fiberscope due to radiation in an inspection apparatus using a fiberscope used for visual inspection in a radiation environment.

Traditionally, radiation-resistant types have been used for visual inspection under high radiation conditions.
ITV cameras or radiation-resistant fiberscopes were used. The configuration and problems of conventional inspection devices of this type will be explained with reference to FIGS. 1 to 4. Figure 1 shows a part of the configuration of an inspection device using an ITV camera, and shows an inspection surface 2 of an object to be inspected 1 (a partial surface or the entire area of the object to be inspected 1).
When performing visual inspection of Side 2
is irradiated by the light source section 6, and a visual inspection is performed.

However, the conventional
In inspection equipment using ITV cameras, ITV
Due to the large size and weight of the camera 4, the size and weight of the inspection tool 3 increase in terms of strength, and furthermore, the device configuration becomes quite large due to the routing of cables 7, etc. It had That is, it has the disadvantage that the inspection device becomes quite large.

Therefore, an inspection device using a fiberscope was developed to replace the ITV camera. That is, the second
As shown in the figure, the inspection tool 3 has a fiberscope 8 attached thereto in place of the ITV camera, thereby improving the above-mentioned drawbacks caused by the ITV camera.

However, in each of these inspection devices,
A common problem was that problems such as deterioration of sensitivity occurred due to the effects of high radiation environments. In other words, as an effect under a specific radiation environment, even when using an ITV camera as shown in Figure 1,
Similarly, when the fiberscope shown in the figure is used, as shown in Fig. 3, the ITV
A phenomenon occurs in which the sensitivity dB of the camera or fiberscope or the S/N on the inspection signal is significantly impaired. This indicates that consistent testing is virtually impossible during the testing process.

Here, an inspection apparatus using a fiberscope will be described in more detail with reference to FIG. 4. In FIG. 4, the same parts as in FIGS. 1 and 2 described above are designated by the same reference numerals. The fiberscope 8 has an objective lens section 1
1 to project the inspection surface 2, and fiberscope 8
The objective lens section 12 provided on the opposite side of the
A configuration is adopted in which the imaging device 13 images the inspection surface 2.
Then, the image capturing device 13 converts the image into an electrical signal 14.
The system configuration is such that the signal is converted into a signal, inputted to a processing device (generally an image processing device) 15, and subjected to signal processing and visual inspection. In such a configuration, those actually exposed to the radiation environment are:
These are the fiberscope 8 itself, the light source section 6, and the objective lens section 11. Therefore, this part 6, 8, 11
Due to the influence of radiation, optical transmission loss (mainly decrease in lens transmittance, increase in fiberscope transmission loss, etc.) occurs, which has a significant impact on visual inspection performance.

The present invention was developed in view of the above circumstances.In an inspection device using a fiberscope used for visual inspection in a radiation environment, a neutral density filter, an optical It is an object of the present invention to provide a compensation device that is equipped with a sensitivity adjustment mechanism including an aperture, an image intensifier, etc., and is capable of appropriately compensating for an increase in optical transmission loss that changes with the time of irradiation with radiation. .

An embodiment of the present invention will be described below with reference to FIG. In FIG. 5, the same parts as in FIG. 4 are given the same reference numerals, and their explanations will be omitted. here,
In order to compensate for the input of the imaging device 13, a neutral density filter 21 having a configuration in which many types of filters with different attenuation rates can be arbitrarily set is provided between the objective lens section 12 of the fiberscope 8 and the imaging device 13, and an optical aperture. A sensitivity adjustment mechanism consisting of an image intensifier 22 and an image intensifier 23 is provided to compensate for an increase in transmission loss due to radiation. 24 is an objective lens for connecting between the image intensifier 23 and the imaging device 13. Further, the light intensity of the light source 6 can be arbitrarily adjusted by a light intensity adjuster 25.

Here, the operation of one embodiment will be explained. The amount of increase in optical transmission loss due to radiation increases due to the integrated dose R, which increases with the time of exposure to radiation, as described above. Here, the increase in transmission loss will be reduced by adjusting the light amount of the light source section 6, the attenuation filter 21, the optical aperture 22, and the image intensifier 23.
This is compensated by a sensitivity adjustment mechanism. Since the image intensifier 23 is usually an ultra-high sensitivity image tube, it is configured to be able to detect up to about 10 ^-5 lux and to allow sensitivity adjustment. Therefore, the sensitivity is more than sufficient for the fiberscope under non-irradiation conditions, and it is too bright as it is, so the amount of light input to the image intensifier 23 is adjusted using the attenuation filter 21 and the optical diaphragm 22. .
In this case, the light amount of the light source section 6 can be adjusted arbitrarily by the light amount adjuster 25, and the light amount of the light source section 6 can be adjusted to an appropriate state according to the setting of the dark filter 21. Then, each time the integrated dose R of radiation increases and the transmission loss increases, the attenuation filter 21 and the optical diaphragm 22 are adjusted to brighten them, and the light intensity of the light source section 6 is adjusted to increase the light intensity. The optical image whose brightness is maintained is input to the image intensifier 23. That is, the imaging device 1
3, a constant optical image can be input at all times. Such a light source section 6, a dark filter 21,
By adjusting the amount of light using the optical diaphragm 22 and the optical diaphragm 22, it is possible to obtain an appropriate optical image even from the non-irradiation state to the cumulative state. Moreover, the slight variations in each adjustment are made constant by the automatic sensitivity adjustment function of the image intensifier 23 itself, and a practical contrast can be obtained.

As mentioned above, by increasing the amount of attenuation in the initial state, and gradually releasing the attenuation as the transmission loss increases due to the increase in the integrated dose of radiation, and returning to normal, the amount of increase in transmission loss can be compensated for. It is possible to conduct a practical visual inspection by compensating for increased transmission loss in a radiation environment.

As described in detail above, according to the compensation device of the present invention, in an inspection device using a fiberscope used for visual inspection in a radiation environment, there is a light reduction device between the fiberscope and the imaging device. By providing a sensitivity adjustment mechanism consisting of a filter, optical diaphragm, image intensifier, etc., it is possible to appropriately compensate for the increase in optical transmission loss that changes with the time of exposure to radiation. A practical visual inspection can be carried out by compensating for the increase in transmission loss.

[Brief explanation of the drawing]

1, 2, and 4 are diagrams showing the configuration of conventional inspection equipment, respectively, and FIG. 3 is the above-mentioned FIG. 1,
2 is a diagram for explaining the transmission loss characteristics with respect to the radiation integrated dose of the inspection apparatus having the configuration shown in FIG. 2, and FIG. 5 is a diagram showing the configuration according to an embodiment of the present invention. 6...Light source section, 8...Fiber scope, 1
DESCRIPTION OF SYMBOLS 1, 12... Objective lens part, 21... Attenuation filter, 22... Optical diaphragm, 23... Image intensifier, 24... Objective lens, 25... Light amount adjuster.

Claims (1)

[Scope of utility model registration request] In an inspection device using a fiberscope for visual inspection in a radiation environment, a light-reducing device is installed between the fiberscope and an imaging device that captures an optical image of the surface to be inspected transmitted via the fiberscope. A compensation device comprising a sensitivity adjustment mechanism including a filter, an optical diaphragm, and an image intensifier, and the sensitivity adjustment mechanism compensates for an increase in transmission loss of an optical system including the fiberscope due to radiation.