JPH0792111A - Method and system for determining depth of defect - Google Patents

Abstract

PURPOSE:To provide a method and system for determining the depth of defect in a specimen. CONSTITUTION:The system for locating a defect in a specimen 5 based on the difference in the transmission amount of X-rays comprises an X-ray source 1, a mechanism 2 for shifting the X-ray source 1, a displacement sensor 3 for the X-ray source 1, a unit 4 for measuring the distance from the X-ray source 1 to the specimen 5 or an X-ray camera 6, the X-ray camera 6, a defect image extracting means 7, and a defect position operating means 8. The X-ray 1 is shifted in parallel with the surface of the specimen 5 and the image thereof is picked up by means of the X-ray camera 6. The defect position operating means 8 determines the depth of a defect 5a in the specimen 5 based on the moving distance of the image of defect 5a on a plurality of images extracted by the defect image extracting means 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect depth position detecting apparatus and method thereof, and is particularly useful for defect inspection using radiation used for nondestructive inspection of equipment such as plants.

[0002]

2. Description of the Related Art Conventionally, a defect detection apparatus using radiation has been used for nondestructive inspection of equipment such as plants.

FIG. 3 shows a defect detecting device according to the prior art. As shown in the figure, in this defect detection apparatus, the X-ray source 1 is installed at a certain distance a from the subject 5, and a film 10 which is sensitive to X-rays is placed on the back side of the subject 5 to detect the defect 5.
Imaging of a is performed.

[0004]

According to the prior art as described above, from the image of the defect 5a obtained on the film 10,
Only the length d of the image of the defect 5a is obtained, and the information on the depth x of the defect 5a is not obtained. That is, in the defect detecting apparatus, only the distribution of the X-ray transmission amount on the plane obtained by integrating the width direction of the object 5 is obtained.
Although position information of a on the plane can be obtained, information cannot be obtained in the depth direction of the defect 5a, and the depth x of the defect 5a cannot be obtained.

The present invention has been made in view of the above-described conventional art, and an object thereof is to provide a defect depth position detecting apparatus and method capable of obtaining the depth position of a defect in an object.

[0006]

The structure of the apparatus according to the present invention which achieves the above object, is a defect depth position for performing flaw detection on a subject by utilizing the difference in the amount of transmission of radiation such as X-rays in the subject. In the detection device, a radiation source that emits radiation such as X-rays, a radiation source moving mechanism that moves the radiation source parallel to the surface of the subject, and a displacement sensor that detects the amount of movement of the radiation source.
A camera that captures an image of the subject by radiation that has passed through the subject, a defect image extraction unit that extracts defects in the subject from image information of the camera, and a distance between the radiation source and the subject and the camera. A distance meter for measuring the displacement sensor,
Based on the output signals of the rangefinder and the defect image extraction means, the moving amount of the defect image at each position taken by moving the radiation source, the moving amount of the radiation source, the distance between the radiation source and the subject, and the subject And a camera, the defect position calculating means for calculating the depth position of the defect in the subject based on the distance between the camera and the camera.

The structure of the method according to the present invention which achieves the above object is a defect depth position detecting apparatus for detecting flaws in an object by utilizing the difference in the amount of transmission of radiation such as X-rays in the object. A radiation source that emits radiation toward the subject is moved parallel to the surface of the subject and the subject is photographed with a camera at each position, and the amount of movement of the defect image in the subject at this time The depth position of the defect in the subject is obtained based on the moving amount of the radiation source, the distance between the radiation source and the subject, and the distance between the subject and the camera.

[0008]

According to the present invention having the above construction, the radiation source can be moved by the radiation source moving mechanism, and the amount of movement is detected by the displacement sensor for detecting the amount of movement. The distance between the radiation source and the subject can be measured with a rangefinder, and the image of the defect obtained by the camera is
The position is extracted by the defect image extracting means. The defect position calculating means determines the depth position of the defect on the basis of the amount of movement of the radiation source and the amount of movement of the defect image thus obtained, and the distance relationship between the radiation source and the object and the distance between the radiation source and the camera.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

As shown in FIG. 1, the X-ray source 1 is moved in parallel with the surface of the subject 5 by a radiation source moving mechanism 2, and
It is configured to emit X-rays toward the subject 5. An image obtained by photographing the subject 5 with the X-ray source 1 fixed at a certain position is captured by the X-ray camera 6 as image information.

The displacement sensor 3 detects the amount of movement of the X-ray source 1 by the radiation source moving mechanism 2 and supplies information on this amount of movement to the defect position calculating means 8. The range finder 4 is fixed to the X-ray source 1, and the distance between the X-ray source 1 and the subject 5 and the X-ray sources 1 and X are fixed.
The distance to the line camera 6 is detected and information on these distances is supplied to the defect position calculating means 8. Defect image extraction means 7
Processes the image captured by the X-ray camera 6.
In other words, the image captured by the X-ray camera 6 has a different brightness from the surroundings when a defect exists, and this is used to extract the position of the defect image. The result display output device 9 is
The result calculated by the defect image extraction means 7 is displayed.

When detecting the depth position of the defect 5a of the object 5 using the defect depth position detecting apparatus according to this embodiment, the X-ray source 1 is placed at a certain position as shown in FIG. The result of fixing and imaging the subject 5 is captured as image information by the X-ray camera 6, and when the defect 5a exists in this image information, the position of the defect 5a is determined by utilizing the fact that the brightness is different from the surroundings. It is extracted by the defect image extracting means 7. Further, by the distance meter 4 attached to the X-ray source 1, the distance between the X-ray source 1 and the subject 5: a, and the X-ray source 1
And a distance between the X-ray camera 6 and a + b are measured.

Next, the position of the X-ray source 1 is moved by the radiation source moving mechanism 2. The amount of movement at this time is measured by the displacement sensor 3. Then, as in the previous case, the X-ray camera 6 captures the imaging information of the subject 5 at the position of the X-ray source 1, and the defect image extraction means 7 extracts the position of the image of the defect 5a.

The defect position calculating means 8 takes in the following values obtained as a result of the above, respectively, and calculates and obtains the depth position of the defect 5a. (1) Distance between X-ray source 1 and subject 5: a (2) Distance between X-ray source 1 and X-ray camera 6: a + b (3) Moving amount of X-ray source 1: d (4) Each X Image positions of the defect 5a of the inspection result of the subject 5 at the position of the radiation source 1: f1 and f2

The position of the defect 5a obtained by the defect position calculating means 8 is output and displayed by the result display output device 9.

The defect position calculating means 8 moves the X-ray source 1 in parallel with the surface of the subject 5 and the surface of the X-ray camera 6 and performs the following defect depth calculation processing. (1) Amount of movement of defect image: fd is obtained. From the defect image positions: f1 and f2 at the position of each X-ray source 1, the defect image movement amount: fd is obtained. fd = f2-f1 (1) (2) Defect depth position: x is calculated. X-ray source 1 movement:
d, the amount of movement of the image of the defect 5a: fd, the distance from the X-ray source 1 to the subject 5: a, the distance from the subject 5 to the X-ray camera 6: b, and the defect depth: x It is calculated from the relationship of the formula. a + x: b−x = d: fd (2) x = (b × d−a × fd) / (d + fd) (3) Using the above formula (3), Plate thickness: Even if t is unknown,
The defect depth: x from the surface of the subject 5 is obtained.

The defect position in the plane direction perpendicular to the depth direction of the object 5 can be obtained from the extraction position of the image of one defect 5a.

[0018]

As described above in detail with reference to the embodiments, according to the present invention, even if the exact plate thickness of the subject is unknown,
The depth position of the defect in the subject can be detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing an apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the measurement principle of the present invention.

FIG. 3 is a block diagram showing a device according to the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray source 2 Radiation source moving mechanism 3 Displacement sensor 4 Distance meter 5 Subject 5a Defect 6 X-ray camera 7 Defect image extraction means 8 Defect position calculation means

Claims (2)

[Claims] 1. A defect depth position detecting device for detecting flaws in an object by utilizing a difference in the amount of radiation such as X-rays transmitted through the object, and a radiation source that emits radiation such as X-rays and this line. A radiation source moving mechanism that moves the source parallel to the surface of the subject, a displacement sensor that detects the amount of movement of the radiation source, a camera that captures an image of the subject due to radiation that has passed through the subject, and a camera of this camera. Defect image extraction means for extracting defects in the object from image information, rangefinder for measuring the distance between the radiation source and the object and camera, and outputs of the displacement sensor, rangefinder and defect image extraction means Based on the amount of movement of the defect image at each position taken by moving the radiation source based on the signal, the amount of movement of the radiation source, the distance between the radiation source and the subject, and the distance between the subject and the camera Defect position that calculates the depth position of the defect in the object Defect depth and having a calculation unit position detecting device. 2. In a defect depth position detecting device for detecting flaws in a subject by utilizing a difference in the amount of transmission of radiation such as X-rays in the subject, a line for radiating radiation such as X-rays toward the subject. The source is moved in parallel to the surface of the subject, and the subject is photographed by the camera at each position, and the movement amount of the image of the defect in the subject at this time, the movement amount of the radiation source, the radiation source and the subject A defect depth position detecting method, comprising: determining a depth position of a defect in a subject based on a distance between the subject and a camera and a distance between the subject and a camera.