JPH06118062A - Defect recording and regenerating method for nondestructive inspection - Google Patents

Abstract

PURPOSE:To provide a defect recording and regenerating method in which a defect indicating pattern can be easily and surely recorded and regenerated with high efficiency by remote control, to a test body having a curved inspection surface for nondestructive test, without requiring an inspector to directly enter an inspection part to record it. CONSTITUTION:At the nondestructive inspection of a test body 1 having a curved inspection surface, a scale 12 showing a two-dimensional coordinate is arranged on the inspection surface of the test body 1. A visually confirmable defect indicating pattern 3 is formed on the inspection surface, and the scale 12 and the defect indicating pattern 3 are recorded as the same camera image together with photographing information such as photographing angle and distance. At defect judgment, the recorded image is regenerated to extract the defect indicating pattern 3 to be judged, and the position, dimension and distribution of the extracted defect indicating pattern 3 are provided as three- dimensional information by the operation based on the scale indicating value and the photographing information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-destructive inspection defect recording / reproducing method applied to non-destructive inspection of blades of a water turbine runner, for example, by a penetrant inspection test or a magnetic particle test.

[0002]

2. Description of the Related Art As is well known in the art, non-destructive tests such as a penetrant flaw test and a magnetic particle flaw test have been carried out as flaw detection tests for turbine runners, which are parts of turbine generators. In these test methods, a defect indicating pattern that can be visually observed is formed on the inspection surface of the test piece, and the position of this defect indicating pattern,
Defect determination is performed based on dimensions, distribution, and the like.

Conventionally, in such a defect inspection of a blade of a water turbine runner, an inspector enters the running water surface and visually observes a defect indicating pattern formed on the inspection surface, and scales from a predetermined reference point or reference line. It was general to find the defect position on the curved surface using.

[0004]

However, since the blade surface of the turbine runner has a three-dimensionally twisted curved surface shape, it takes a lot of time to record the defect position and size based on the defect indication pattern. It takes labor. In particular, when the water turbine runner is made of cast steel, the defect indicating pattern tends to be irregularly distributed, more time and labor are required, and the defect measurement accuracy tends to vary.

Further, since the running water surface of the water turbine runner is a narrow portion, the measurement work on the running water surface is troublesome, and the defect indication pattern by the nondestructive inspection may be spoiled. Especially in a water turbine runner with a high head, the working space becomes even smaller, and it may be difficult for an inspector to even enter the runner running surface.

The present invention has been made in view of the above circumstances, and it is necessary for an inspector to directly enter and record on a test body for a non-destructive test surface having a curved test surface. It is an object of the present invention to provide a non-destructive inspection defect recording / reproducing method capable of easily and efficiently recording / reproducing a defect indication pattern by remote operation.

[0007]

In order to achieve the above object, a defect recording / reproducing method for non-destructive inspection according to the present invention comprises:
A scale showing two-dimensional coordinates is arranged on the inspection surface of the test body, and a visible defect indicating pattern is formed on the inspection surface, and the scale and the defect indicating pattern are taken as the same camera image. When the defect is judged, the recorded image is reproduced to extract the defect design pattern to be judged, and the position, size and distribution of the extracted defect design pattern are recorded on the scale. It is characterized in that it is obtained as three-dimensional information by a calculation based on an instruction value and the photographing information.

[0008]

According to the present invention, the defect indicating pattern can be recorded and reproduced by remote control at any operation position by simply disposing the camera near the test body. It is not necessary to go into the part and directly measure the position, size, etc. of the design pattern. Therefore, even in a narrow inspection space, extra time and labor are not required, and the defect indication pattern is not touched to damage the pattern, and the defect indication pattern is accurately and not overlooked, and highly accurate and short. Record on time
It can be reproduced and the reliability can be improved.

Further, even if the inspection surface has a curved shape which is three-dimensionally twisted, the indication value of the scale arranged on the inspection surface,
Since the defect indicating pattern is three-dimensionally converted by the calculation based on the photographing information such as the camera photographing angle and the distance, it is possible to obtain a highly accurate inspection result.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this example, a turbine runner is used as a test body, and the recording of the position, size, distribution, etc. of the defect indication pattern generated by the penetrant flaw detection test method or the magnetic particle flaw detection test method or the like on the blade portion or the blade root portion of the runner is recorded.・ Playback is performed.

FIG. 1 shows an apparatus configuration for carrying out the present invention. In FIG. 1, a defect indicating pattern 3 is formed on a blade portion 2 or a blade root portion of a runner 1 which is a test body. A video camera 4 for shooting the defect indication pattern 3 is provided, and an image taken by the camera 3 can be recorded / played back by the video tape recorder 5.

The defective image reproduced by the video tape recorder 5 can be observed on the television monitor 6. Then, a frame freeze 7 for fixing the image to be displayed on the TV screen as needed, a phase adjuster 8 for sending this still image as a video image signal with high precision so as not to cause image blur, and this image signal A cursor creator 9 for scanning a light pen on the TV screen while fixed on the TV monitor 6, and a portion scanned by the cursor creator 9 is formed as an image signal, and is superimposed on the still image to be displayed on the TV monitor. And an image synthesizer 11 for transmitting and outputting the image data created by the light pen on the screen to the external computer 10.

Then, as shown in FIG. 1, at the time of recording by the video camera, the scale 12 is arranged in the vertical and horizontal directions on the surface of the runner. At least three reference marker points 13 are imprinted on the screen on the surface of the runner, whereby a defect indicating pattern is recorded.

At the time of inspection, the defect indicating pattern 3 generated on the blade portion 2 of the water turbine runner 1 is photographed by the video camera 4 and recorded / reproduced by the video tape recorder 5 to extract a desired defect distribution image. . This extracted image is
In order to suppress variations in data fetching at the time of writing image data by the light pen 14 on the television screen 6, it is transmitted to the image synthesizer 11 via the phase adjuster 8.

The position of the defective portion is scanned by the light pen 14 on the defect indicating pattern distribution of the test body displayed on the television screen 6 as described above, and the predetermined scale of the scale arranged on the surface of the test body is scanned. By designating the length interval, these results are transferred from the cursor creator 9 to the image synthesizer 1.
Input to 1. In this way, the scanning result by the light pen 14 is displayed on the television screen together with the extracted image data, but only the image data by the light pen is transmitted and output to the external computer 10. The image data input to the computer 10 is input to the computer 10 and displayed on the display 15 attached to the computer 10.

Further, the computer 10 is input from the size of the screen input as image data and a computer terminal or the like. The image data is converted into the actual length from the value of the actual dimension length of the dimension on this screen, and the display in the actual length is also performed. Here, generally, in order to develop an image of a three-dimensional screen on a two-dimensional screen using a coordinate system along the curved surface of the test body, the following method is used in this embodiment.

That is, the water turbine runner blade shape generally has a three-dimensional shape, and is considered to be partially a quadric surface shape. That is, assuming that the shape of the inspection surface included in the recording visual field of the video tape recorder 5 can be expressed by a quadric surface, these shapes are expressed by the following equations.

[0018]

[Equation 1] Here, x, y, and z are three-dimensional orthogonal coordinate systems, and aij
Is a constant. Furthermore, since the recorded image of the video tape recorder is displayed as a two-dimensional plane on the TV screen,
A three-dimensional shape is represented by the following formula on the screen.

[0019]

[Equation 2]

Here, in order to make the runner blade surface simpler, the curved surface shape is expressed by the following equation. Note that x ′ and y ′ are two-dimensional orthogonal coordinate systems, and bij
Is a constant.

[0021]

[Equation 3] That is, as shown in FIG. 2, the blade surface of the runner 1 is regarded as a cylindrical surface 16, and the area recorded by the video camera has a radius R.
It is considered to be a part of the cylindrical surface of.

Therefore, the projected image on the xz plane is displayed on the television screen. Generally, after the image is rotated in the xz plane, the inclination of the blade surface is corrected to make a defect. The coordinate values of the instruction pattern 3 are roughly obtained.

The procedure for calculating the coordinate place according to the above will be described below. That is, when the defect designating pattern 3 is recorded, it is generally recorded from a direction inclined to the blade surface and also to the modeled cylindrical shape.

For example, as shown in FIG. 3A, when the band visual field range is tilted by an angle α, and when the field of view of the blade is simulated by a cylinder having a radius R, the center of the camera does not coincide with the center of the cylinder. When the recording is performed by inclining to the plane including the runner center axis, the recording is performed as in the recording screen example of FIG.

That is, the recorded screen is the real coordinate system x,
z′- in FIG. 3 (B), which is coordinate-converted for y and z
x ′ coordinate system, and a screen-specific coordinate system z−
The position dimension will be measured at x. Therefore, in the present embodiment, the correction of the inclination angle α with respect to the blade cylinder axis and the correction for the curved surface recording are performed.

First, the inclination angle α is corrected as follows. The z'-x 'coordinate system and the zx coordinate system on the recording screen are rotated so that the coordinate axis directions coincide with each other, and the z axis on the screen coincides with the z'axis of the blade cylindrical surface. The following processing is carried out. That is, referring to FIG. 4, the length h on the screen
When measured as, the actual length a is expressed by the following equation. However, it is known that the value measured as h1 on the scale imprinted on the screen has an actual length of a1.

[0027]

[Equation 4] Here, b is the distance from the camera position S to the test body measuring unit as shown in FIG. As a special example, h1 = h2 is set here.

If b and α are known from the above equation, the actual length a can be converted from the height h on the screen, but the numerical values h1 and a1 and h2, a2 on the screen are known. ,
Α and b can be obtained by the following equation.

[0029]

[Equation 5] Next, regarding the cylindrical curved surface, the following calculation formula is established according to FIG.

[0030]

[Equation 6] From the above, the relation between θ'1 and θ'2 is obtained in the same way as the equation using a1 and a2.
Two equations hold, and b, θ′1 and θ′2 can be determined. Therefore, since the three points in the above figures A, B, and C are located on the circumference of the circle, if the deduction of the coordinate systems u and v is B, the following equation holds for the equation of the circle.

[0031]

[Equation 7] And k1 and k2 can be obtained from the equations (2) and (3),
R can be obtained from the equation (1), and θ0 can be obtained from the equation already described.
Can also be obtained. Therefore, for the actual length l, using the above equation, knowing b, R, θ0 from the reading of h,

[0032]

[Equation 8] From, l can be obtained. Next, a method of connecting images will be described with reference to FIG.

The respective screens 17 and 18 in FIG. 6 are obtained by converting the image by the above-mentioned method, and the positions of the markers 13 on the blade surface at arbitrary three points common to each other are set to points A, B and C. , For example, distances a and a'between A and B, and AB from point C
The distances up to the line are measured as b and b ', respectively, and are reduced and expanded in the AB direction and the direction orthogonal thereto, and both screens 17,
By connecting points A, B, and C of 18 to each other, both screens are connected. As described above, in the present embodiment, the runner blade surface is approximated to a cylindrical surface, and the ratio between the size on the screen and the actual size can be calculated according to the expression of the cylindrical surface to determine the actual size at any position on the screen. . Of course, according to the present invention, the actual dimension can be known from the dimension measurement value on the screen according to the same idea as long as it is a three-dimensional curved surface shape that can be expressed by an arithmetic expression, not limited to the cylindrical surface.

If the relationship between the scale projected on the screen and the position reference for measuring the defect design pattern is known in advance,
Of course, the defect position can be obtained in the desired coordinate system.

According to the present embodiment described above, various defect indication patterns 3 appearing on the water turbine runner 1 can be obtained by recording / reproducing images taken by the video camera 4 as the defect indication patterns 3 generated on the water turbine runner. Can be observed from any direction,
Of these defect indication patterns appearing on the monitor television 6, an arbitrary screen is extracted at a position that is most suitable for recording and observation, and the shape of the test body and the defect position are displayed on the extracted screen on the monitor TV screen. Can be instructed by the light pen 14.

By this, the relative relationship between the position of the defect and the shape of the test piece can be recorded, and in order to measure the position dimension of the defect accurately, the scale 12 is arranged in the defect measuring section and is imprinted on the image. It can be used as a defect position calculation reference value. Therefore, in calculating the position dimension of the defect, the scale of the scale can be easily converted by modeling the shape of the test body into a relatively simple shape such as a cylindrical shape or a flat plate. Further, when the flaw detection area of the test body is large and the flaw detection area cannot be sufficiently included in one screen, it is possible to create a record of the entire predetermined area by connecting the images. In this case, by performing image recording so that at least three mark points included in the image are included in other images that need to be connected, the coordinates of both images are transformed, and the above three points are completely converted. It is possible to satisfy the reliable image connection by superimposing them on.

As described above, it is possible to easily and accurately record and display the position and the size distribution of the visually inspected defect indicating pattern at a place where the video camera record can be reproduced, not at the runner installation site. Becomes

Although the runner blade shape is partially approximated to a cylindrical shape in the above embodiment, the position dimensions of the same defect are measured on various screens recorded by a video camera,
By averaging the results of multiple screens, it is possible to calculate the position dimensions with high accuracy.

[0039]

As described above, according to the present invention, it is not necessary for an inspector to directly enter an inspection site and record on a test object having a curved inspection surface for non-destructive testing, and remote inspection is possible. It is possible to record and reproduce the defect indication pattern easily and with high efficiency and reliability by a manual operation. That is, since the defect indication pattern on the inspection surface of the test body is recorded as a camera image together with the scale arranged on the surface of the test body, it is necessary to measure the size and position of each defect on the scale as in the conventional case. In addition, the position dimension of the defect can be obtained without image reproduction. Therefore, the time for occupying the test body for the inspection is significantly shortened, and the inspection accuracy is improved. In addition,
By recording common marks or landmarks on multiple recorded screens, the inspection accuracy can be improved by connecting and averaging the screens.

[Brief description of drawings]

FIG. 1 is a diagram showing an apparatus configuration for implementing a recording / reproducing method according to an embodiment of the present invention.

FIG. 2 is a diagram showing modeling of a test object shape in the example.

3A and 3B are views for explaining image display by image recording of the same embodiment.

FIG. 4 is a diagram for explaining image tilt correction in the runner axis direction.

FIG. 5 is a diagram illustrating correction of image distortion of a cylindrical curved surface.

FIG. 6 is a diagram illustrating a method of connecting screens.

[Explanation of symbols]

 1 Specimen (runner) 2 Inspection surface (blade) 3 Defect indication pattern 4 Camera (video camera) 5 Video tape recorder 6 Monitor TV 9 Cursor creator 10 Computer 12 Scale

Claims (1)

[Claims] 1. A non-destructive inspection of a test object having a curved inspection surface, a scale showing two-dimensional coordinates is arranged on the inspection surface of the test object, and a visible defect indicating pattern is provided on the inspection surface. The scale and the defect indication pattern are recorded as the same camera image together with the photographing information such as the photographing angle and the distance, and at the time of defect determination, the recorded image is reproduced and the defect instruction pattern to be determined. The defect recording / reproducing method for nondestructive inspection, characterized in that the position, size and distribution of the extracted defect indicating pattern are obtained as three-dimensional information by calculation based on the scale indicating value and the photographing information. .