JPH0138570Y2 - - 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 fabric scope 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. Fig. 1 shows a part of the configuration of an inspection device using an ITV camera.
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. 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 for the effects under a specific radiation environment, the effects of radiation exposure are the same when using an ITV camera as shown in Figure 1, and when using a fiberscope as shown in Figure 2. As shown in Figure 3, for the integrated dose R of radiation accumulated over the examination time h,
ITV camera or fiberscope sensitivity dB,
Alternatively, a phenomenon occurs in which the S/N on the test 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 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 such a configuration, it is the fiberscope 8 itself, the light source section 6, and the objective lens section 11 that are actually exposed to the radiation environment. Therefore, optical transmission loss (mainly decrease in lens transmittance, increase in fiberscope transmission loss, etc.) occurs in these parts 6, 8, and 11 due to the influence of radiation, which has a significant effect on visual inspection performance. give.

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
The imaging device includes an optical amplifying device, and automatically controls the amplification degree of the optical amplifying device and the amount of light of a light source that illuminates the inspection surface of the object based on an input light amount photometric signal of the imaging device. An object of the present invention is to provide a compensation device that can maintain a constant light-receiving sensitivity 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 the drawings. 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,
Between the objective lens unit 12 of the fiberscope 8 and the light-receiving surface of the imaging device 13, there is a light amount photometry unit 21 including an objective lens, and an optical amplification unit for compensating the amount of transmission loss of the fiberscope 8 etc. in a radiation environment. Image intensifier 22 as a device
will be provided. As shown in FIG. 6, the light amount photometry section 21 includes a half mirror 31, an objective lens 32,
and a photo sensor (with a built-in lens) 33, etc., and is configured to obtain an input light amount photometry signal S _f of the imaging device 13 from the photo sensor 33. or,
In FIG. 5, 23 is a control device, and based on the photometry signal S _f obtained from the light amount photometry section 21,
The optical amplification degree of the image intensifier 22 and the light amount of the light source 6 are controlled so that the optical image input to the imaging device 13 is always at a constant level, that is, the light receiving sensitivity of the imaging device 13 is always kept 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 input to the imaging device 13 via the image intensifier 22 and the light amount photometer 21. At this time, the input light amount of the imaging device 13 is measured by the light amount photometry section 21, and the photometry signal S _f is input to the control device 23. This photometric signal S _f serves as a reference signal indicating the amount of transmission loss of the fiberscope 8. Based on this photometric signal S _f , the control device 23 controls the light intensity of the light source section 6 and the image intensifier 22.
Automatic compensation for the amount of transmission loss of the fiberscope 8 is performed to control the optical amplification degree of the fiberscope 8 so that the optical image input to the imaging device 13 is always in an optimal state, that is, to keep the light receiving sensitivity in the imaging device 13 constant. Let's do it. As a result, even if the amount of optical transmission loss in the fiberscope 8 etc. increases in a radiation environment and the brightness of the optical image output from the fiberscope 8 decreases, this can be absorbed by the image intensifier 2.
2, the amount of transmission loss can be sufficiently compensated with an appropriate degree of optical amplification according to the amount of transmission loss, and a constant optical image can always be input to the imaging device 13, so that visual inspection can be performed using a stable image.

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 light source light intensity is 1 lux, then (dB=10logA), the photocathode illuminance is 1/100
The lux has decreased. Therefore, if the increase in loss due to radiation is 30dB/100m, the overall amount is ~
It becomes about 50dB/100m, which is reduced to 1/10 ⁵ . Therefore, since compensation cannot be achieved only by increasing the amount of light from the light source, an image intensifier 22 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).

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

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 light amount of a light source that illuminates the inspection surface of the object to be inspected are determined based on the input light amount measurement signal of the imaging device. By adopting a configuration that automatically controls the image pickup device, it is possible to maintain a constant light-receiving sensitivity of the imaging device and automatically compensate for the increase in transmission loss in a radiation environment, making it possible to perform visual inspections with always stable images. .

[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 integrated radiation dose of the inspection device configured as shown in FIG. 2, FIG. FIG. 3 is a diagram showing the configuration of a light amount photometry section in FIG. 6...Light source section, 8...Fiber scope, 1
1, 12...Objective lens section, 13...Imaging device,
21... Light amount photometer, 22... Image intensifier, 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 provided 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 amount photometry unit that measures the input light amount of the imaging device, a light source unit that irradiates the surface to be inspected, and an amplification degree of the optical amplification device based on the photometry output signal of the light amount photometry unit; and a control device that controls the amount of light from the light source section,
A compensation device that compensates for an increase in optical transmission loss in a radiation environment by controlling the amount of light and controlling the degree of optical amplification of the control device.