JPH0134167Y2 - - 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. 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 a concrete influence under the radiation environment, even when using an ITV camera as shown in Figure 1,
Similarly, when using a fiberscope as shown in FIG. 2, as shown in FIG. 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 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.
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, this part 6,
8 and 11, an optical transmission loss (mainly a decrease in lens transmittance, an increase in fiberscope transmission loss, etc.) occurs due to the influence of radiation, which has a significant effect on visual inspection performance.

Therefore, a type of optical amplifier called an image intensifier is installed in front of the imaging device 13 (input stage), and the above transmission loss is compensated for by adjusting the sensitivity of the image intensifier and adjusting the light amount of the light source section 6. It was thought to do this. However, this transmission loss compensating means has a structure that does not take color information of the inspection surface into consideration, and does not have an apparatus configuration that allows visual inspection using a color image while keeping the inspection surface in a stable state.

The present invention was developed in view of the above-mentioned circumstances.In an inspection device using a fiberscope used for visual inspection in a radiation environment, the optical image output from the fiberscope is
After separating color information into the three primary colors of (red), G (green), and B (blue), each color information is amplified by an image intensifier, captured by an imaging device, and the resulting image information is mixed. , comprising means for obtaining a colored video signal, and means for separately measuring the light intensity of each of the color information and controlling the amplification degree of at least each of the image intensifiers based on the measurement signal, It is an object of the present invention to provide a compensation device that automates the compensation of transmission loss due to radiation and the compensation of color information, and enables stable visual inspection using color images.

An embodiment of the present invention will be described below with reference to the drawings.

This invention uses an image intensifier to compensate for the transmission loss of a fiberscope in a radiation environment for each color information of the three primary colors, R, G, and B, and also automates the compensation for the transmission loss and the color information. This enables stable visual inspection using images. Here, the wavelength characteristics of the fiberscope are as shown in Figure 5, in the visible range (about 400 nm).
It has a sufficient light transmittance at wavelengths of up to 800 nm), and therefore it is fully possible to transmit color images. still,
Although the vertical axis in FIG. 5 is expressed as transmission loss, it may also be interpreted as transmittance or sensitivity. However, the wavelength characteristics of the image intensifier are
As shown in Figure 6 a and b, the photocathode sensitivity on the input side (see figure a) is excellent, but the phosphor screen output on the output side (see figure b) is ±50 nm around 530 nm.
However, this method cannot be used for color images. Therefore, the present invention has developed the optical images output from the fiberscope into R (red), G (green), and B
(Blue) After separating the color information into the three primary colors, each individual color information (R, G, B) is amplified by an image intensifier to compensate for transmission loss, and each image intensifier is amplified by each image intensifier. This system combines the optically amplified color information to obtain a colored video signal, and also automates the transmission loss compensation and color information compensation.

FIG. 7 is a diagram showing an embodiment of the present invention. In FIG. 7, the same parts as in FIG. 4 are given the same reference numerals, and their explanations will be omitted. Here, the output optical image obtained from the objective lens section 12 of the fiberscope 8 is separated into color information of the three primary colors R, G, and B by a color separation optical system 20 configured as shown in FIG. In FIG. 8, CF is a correction film. The three color information of R, G, and B separated by this color separation optical system 20 is optically amplified by respective image intensifiers 21 _R , 21 _G , 21 _B , and a light amount photometer 22 including an objective lens. ,... respectively corresponding imaging devices 23 _R ,
It is input to _23G and _23B . And R, G, _B obtained from each of the above-mentioned imaging devices 23 _R , 23 _G , 23 B
The respective color information is input to the video converter 24, where it is mixed and converted into a color video signal. In addition, the light amount photometering section 22,... is a half mirror 3 as shown in FIG.
1. A configuration that is composed of an objective lens 32, a photo sensor (with built-in lens) 33, etc., and obtains input light amount photometric signals S _fR , S _fG , and S _fB of the corresponding imaging devices 23 _R , 23 _G , and 23 _B from the photo sensor 33 . There is. Further, in FIG. 7, 25 is a control device, and the photometry signal obtained from the light amount photometry section 22, . . .
Based on S _fR , S _fG , S _fB , the optical amplification of the image intensifiers 21 _R , 21 _G , 21 _B and the light amount of the light source 6 are controlled, and the imaging devices 23 _R , 23 _G ,
_23B , so that the optical image input to 23B always has a constant light intensity, that is, the imaging devices _23R , _23G , _23B
Automatic compensation control is performed for each optical image of each color with respect to the amount of transmission loss in order to always keep the light receiving sensitivity constant.

Here, the operation of one embodiment will be explained. The fiberscope 8 observes the inspection surface 2 using illumination from the light source 6. The optical image from this fiberscope 8 is input to a color separation optical system 20 via an objective lens 12. As shown in FIG. 8, the color separation optical system 20 separates the input optical image into R (red), G (green), and B.
(blue) color information. Further, the separated color information (optical image) is optically amplified by image intensifiers 21 _R , 21 _G , 21 _B separately for each color, and the objective lenses 32 of the light amount photometry sections 22, . . . are provided correspondingly. are input to the corresponding imaging devices 23 _R , 23 _G , and 23 _B via the .
As a result, the signals output from the imaging devices 23 _R , 23 _G , and 23 _B become color information signals equivalent to the actual colors. These color information signals are input to the video converter 24 and mixed to form a colored electric signal (video signal).
After being converted into , it is input to an image processing device (not shown). Note that from the video converter 24, the image capturing device 2
A signal for synchronization is sent to _3R , _23G , and _23B . At this time, each imaging device 23 _R , 23 _G , 23
A light amount photometry unit 22, each having a unique input light amount of _B ;
..., and the photometric signals S _fR , S _fG , S _fB are input to the control device 25 . This photometric signal S _fR ,
S _fG and S _fB serve as reference signals indicating the amount of R, G, and B transmission loss of the fiberscope 8. Based on the photometric signals S _fR , S _fG , and S _fB , the control device 25
The light intensity of the light source section 6 and the optical amplification degree of the image intensifiers 21 _R , 21 _G , 21 _B are controlled so that the optical images input to the imaging devices 23 _R , 23 _G , 23 _B are always in an optimal state. , that is, each imaging device 2
In order to keep the light receiving sensitivity constant at _3R , _23G , and _23B and obtain the optimal color image,
Automatic compensation for the amount of transmission loss of the fiberscope 8 is performed. Further, the light intensity adjustment of the light source 6 by the control device 25 is performed by increasing the light intensity in stages according to the amount of increase in transmission loss, and adjusting the sensitivity (input) of the intensifiers 21 _R , 21 _G , and 21 _B for each color information. , control so that an appropriate optical image is obtained and color reproducibility is obtained. In addition, color reproducibility can be maintained by controlling the ratio to maintain an appropriate color balance for the initial value, which is naturally expected to result in slight differences in the rate of change between wavelengths due to radiation. . As a result, even if the amount of optical transmission loss in 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 can be absorbed by the image intensifier 21 _R , 21 _G and 21 _B , each of R, G, and B can be sufficiently compensated for with an appropriate amplification degree according to the amount of transmission loss, and a constant optical image can be provided to the imaging devices 23 _R , 23 _G , and 23 _B. Since input is possible, visual inspection can be performed using stable color images.

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 amount is 1 lux, the photocathode illuminance is reduced to 1/100 lux from (dB=10 logA). Therefore, if the increase in loss due to radiation is 30 dB/100m, the total will be ~50 dB/100 m.
It will be about 100m, which will be reduced to 1/10 ⁵ . Therefore, since compensation cannot be achieved only by increasing the amount of light from the light source, the image indensifiers 21 _R , 21 _G ,
21 _B is used in combination. 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 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, the optical image output from the fiberscope is converted to R( After separating color information into the three primary colors of red), G (green), and B (blue), each color information is amplified by an image intensifier, captured by an imaging device, and the image information is mixed. means for obtaining a colorized video signal; and means for separately measuring the light intensity of each of the color information and controlling the amplification degree of at least each of the image intensifiers based on the measurement signal; Compensation of transmission loss by,
And by automating the compensation of color information, stable visual inspection using color images can be performed.

[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,
FIG. 5 is a diagram showing the wavelength characteristics of the fiberscope, and FIGS. FIG. 7 is a diagram showing the configuration of an embodiment of the present invention. FIG. 8 is a diagram showing the configuration of the color separation optical system in the above embodiment. FIG. 9 is a diagram showing the light intensity photometry in the above embodiment. FIG. 6...Light source section, 8...Fiber scope, 1
DESCRIPTION OF SYMBOLS 1, 12... Objective lens part, 20... Color separation optical system, 21 _R , 21 _G , 21 _B ... Image intensifier, 22... Light quantity photometry part, 23 _R , 23
_G , 23 _B ...imaging device, 24...video converter, 2
5...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 optical image of the surface to be inspected obtained from the fiberscope is divided into R, G,
a color separation optical system that separates the color-specific optical images of the three B primary colors; first, second, and third image intensifiers that separately amplify the color-specific optical images separated by the color separation optical system; First, second, and third imaging devices separately capture the color-specific optical images obtained from each image intensifier, and the color-coded image is created by mixing the color-specific optical image information obtained from each of the image capturing devices. a video converter to obtain the signal;
first, second, and third light amount photometry units that are provided at predetermined positions between the color separation optical system and each of the image pickup devices and separately measure the intensity of each color-specific optical image, and each of the light amount photometers; and a control device for controlling at least the amplification degree of each image intensifier based on the measurement signal for each color-specific optical image obtained from the color-specific optical image, and controlling the increase in optical transmission loss due to radiation for each color-specific optical image. A compensating device characterized by compensating.