JPH0138571Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compensation device for compensating transmission loss due to radiation in an inspection device 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 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. 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, each of these inspection devices has a common problem in that inconveniences such as sensitivity deterioration occur due to the effects of high radiation environments. In other words, as an effect under a specific radiation environment, when using an ITV camera as shown in Figure 1, and when using a fiberscope as shown in Figure 2, the third As shown in the figure, a phenomenon occurs in which the sensitivity dB of the ITV camera or fiberscope or the S/N on the inspection signal is significantly impaired with respect to the integrated dose R of radiation accumulated over the inspection time h. 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 a configuration in which an objective lens section 11 projects the inspection surface 2, and an objective lens section 12 provided on the opposite side of the fiberscope 8 images the inspection surface 2 on an imaging device 13. The image is then converted into an electrical signal (video signal) 14 by an imaging device 13, and then input to a processing device (generally an image processing device) 15 for signal processing and visual inspection. . In this configuration, what is actually exposed to the radiation environment is the fiberscope 8 itself, the light source section 6,
and an objective lens section 11. Therefore, this part 6,
8 and 11, optical transmission loss (mainly decrease in lens transmittance, increase in fiberscope transmission loss, etc.) occurs due to the influence of radiation, which has a significant effect on visual inspection performance.

The present invention was developed in view of the above-mentioned circumstances, and is an inspection device using a fiberscope used for visual inspection in a radiation environment. Between the input imaging device and
A configuration in which an optical amplifying device is interposed, and the amplification degree of the optical amplifying device and the amount of light of the light source that illuminates the inspection surface of the object to be inspected are automatically controlled based on a specific signal indicating the light receiving sensitivity within the imaging device. It is an object of the present invention to provide a compensation device that can maintain constant light-receiving sensitivity in the imaging device and automatically compensate for an increase in transmission loss in a radiation environment.

An embodiment of the present invention will be described below with reference to FIG. FIG. 5 shows the configuration of essential parts in an embodiment of the present invention. In the figure, the same parts as those in FIG. Here, an image intensifier 2 is installed between the objective lens unit 12 attached to the fiberscope 8 and the light-receiving surface of the imaging device 13 as an optical amplification device for compensating for transmission loss of the fiberscope 8 and the like.
1 is provided, and the output optical image of the image intensifier 21 is input to the imaging device 13 via a connection (objective) lens 22. Further, a specific light receiving sensitivity output signal (specifically, an image pickup tube output signal or a video signal equivalent to this) is output from the imaging device 13.
This signal is used as a reference signal S indicating the light receiving sensitivity.
is input to the control device 23 as follows. This control device 2
3 controls the optical amplification degree of the image intensifier 21 and the light amount of the light source 6 based on the reference signal S from the imaging device 13, so that the optical image input to the imaging device 13 is always at a constant level. In other words, in order to keep the light receiving sensitivity of the imaging device 13 constant, automatic compensation control for the amount of transmission loss is performed.

Here, the operation of one embodiment will be explained. The optical image on the inspection surface 2 transmitted via the fiberscope 8 is optically amplified by the image intensifier 21 and then input to the imaging device 13 via the connecting lens 22 . At this time, the control device 23 outputs a specific signal indicating the light receiving sensitivity within the imaging device 13, that is, a reference signal S.
Based on this, the light intensity of the light source unit 6 and the amplification degree of the image intensifier 21 are controlled, so that the optical image input to the imaging device 13 is always in an optimal state, that is, the light receiving sensitivity of the imaging device 13 is always controlled. Automatic compensation is performed for the amount of transmission loss of the fiberscope 8 so as to keep it constant. As a result, even if the optical transmission loss of the fiberscope 8 etc. increases in a radiation environment and the brightness (light intensity) of the optical image output from the fiberscope 8 decreases, this is transmitted by the image intensifier 21. Since the amount of loss can be sufficiently compensated for with an appropriate degree of increase according to the amount of loss, and a constant optical image can always be input to the imaging device 13, stable visual inspection can be performed.

Here, to explain the effect in terms of the amount of substantial transmission loss, the fiberscope 8 generates a transmission loss of about 20 dB/100 m even in a non-irradiated state due to its characteristics. If the actual amount of light from the light source is 1 lux (dB=10 logA), the photocathode illuminance is reduced to 1/100 lux. Therefore, if the increase in loss due to radiation is 30dB/100m, the total is ~50dB/100m.
m, and decreases to 1/10 ⁵ . Therefore, since compensation cannot be achieved only by increasing the amount of light from the light source, an image intensifier 21 is also used. As a result, a light-receiving sensitivity up to about 10 ^-5 lux can be obtained, so that the combination with the light source 6 can sufficiently compensate for the above-mentioned transmission loss. Specifically, 1. Compensable range of light source light intensity: Light source light intensity (average illuminance) up to 5000 lux is possible, subject reflectance is about 0.1 to 0.2, therefore 0.1 x 5000 lux to 0.2 x 5000 lux is possible.

2 Compensable range of intensifier up to approximately 10 ^-5 lux (with automatic sensitivity adjustment function).

This 1). ,2). From the effective value of , it can be seen that compensation due to transmission loss is sufficiently possible.

In addition, in the embodiment described above, the control device 23
is based on the reference signal from the imaging device 13, the light intensity of the light source 6, and the image intensifier 2.
Although the configuration is such that the amplification degree of 1 is controlled, it is also possible to adopt the following control means. That is, the amount of increase in transmission loss of the fiberscope due to radiation occurs at a value of several hundred dB/Km. As described above, this increases with the integrated dose R, but the increasing characteristic for each fiberscope is relatively constant. Therefore, if the specifications of the fiberscope are kept constant, the compensation method can be made constant. Therefore, by incorporating the program into the control device 23, it is also possible to temporally control the light amount of the light source 6 and the amplification degree of the image intensifier 21 in accordance with the amount of increase in transmission loss.

As detailed 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, the fiberscope and the An optical amplification device is interposed between an imaging device that inputs an optical image, and the amplification degree of the optical amplification device and the amount of light from a light source that illuminates the inspection surface of the object to be inspected indicate the light receiving sensitivity in the imaging device. By adopting a configuration in which control is automatically performed based on a specific signal, the light receiving sensitivity of the imaging device can be kept constant, and an increase in transmission loss of a fiberscope or the like under a radiation environment can be automatically compensated for.

[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 configured as shown in FIG. 2, and FIG. 5 is a diagram showing the configuration of essential parts in an embodiment of the present invention. 6...Light source section, 8...Fiber scope, 1
1, 12...Objective lens section, 13...Imaging device,
21... Image intensifier, 22...
Connection lens, 23...control device.

Claims (1)

[Scope of utility model registration request] In an inspection device using a fiberscope for visual inspection in a radiation environment, the fiberscope is interposed between the fiberscope and an imaging device that captures an optical image of the surface to be inspected transmitted via the fiberscope. An optical amplification device, a light source unit that illuminates the surface to be inspected, and a specific signal indicating the light receiving sensitivity are input from the imaging device, and based on the signal, the amplification degree of the optical amplification device and the light source unit are determined. 1. A compensation device comprising: a control device for controlling a light amount, and compensating for an increase in transmission loss in a radiation environment through light amount control and optical amplification control of the control device.