JPH01245140A - X-ray fluoroscopic inspection instrument - Google Patents

Abstract

PURPOSE:To obtain an image having a high grade picture quality by providing an image processor for executing a moving integration of an image in conformity with the movement of an object to be inspected, and outputting an integral image signal, and a display device for displaying an integral image processing signal which is sent out of the image processor. CONSTITUTION:A radiant ray 4 which is generated by an X-ray source 1 is radiated to an object to be inspected 2, a part thereof is scattered and absorbed, but a part is brought to transmission as it is and goes to X rays 5. This X rays 5 are detected by a two-dimensional X-ray detector 3 and go to an image signal 10. This signal 10 is sent to an image processor 6 and brought to image integration. In such a case, the object to be inspected 2 is placed on an object-to- be-inspected carrying device 9A and brought to rotational run like a circular arc, therefore, the processor 6 applies the signal 10 to moving integration in conformity with this rotational run, and executes an image synthesis. This synthesized image signal 7 is sent to a display device 8 and displayed. In such a way, an image high in grade picture quality is obtained.

Description

[Detailed Description of the Invention] [Field of Sedentary Work] The present invention provides an X-ray fluoroscopic inspection device that irradiates the inspected object with KX-rays and inspects the inside of the inspected object from the resulting X-ray fluoroscopic image. It is related to.

[Conventional technology]

Figure 4 is a schematic diagram showing the configuration of a conventional XGJ fluoroscopic inspection device, in which (2) is an X-ray source, (2) is an object to be internally inspected, and (3) is an X-ray source generated from (1). The exposed radiation (4) is the object to be inspected (2).The transmitted X-ray (5)
(6) is an image processor that processes the image signal from this two-dimensional X-ray detector (3); (8) is this image processor (6). The display device (9) displays the image signal (7) sent from the
) is a device to be inspected that travels in a straight line and is arranged in a direction perpendicular to

Next, the operation of this conventional device will be explained with reference to FIGS. 5 and 6.

First, a case where the inspected object (2) is smaller than the radiation trajectory (irradiation field of view) will be described. In this case, the X-ray source (1
) Radiation generated by (4) & construction objects to be inspected (2)
Some of it is scattered and absorbed, but some of it is transmitted as it is and becomes transmitted X-rays (5). This transparent X
The ray (5) is detected by the two-dimensional X-ray detector (3) and transmitted
It becomes #j image signal (10). At this time, the object to be inspected (2
) is a metal with a high density, then X, which is radiation (4)
The line is well absorbed by this test object (2) IC. As a result, the intensity of the transmitted X1 (5) decreases, and the transmitted X-ray image signal (lO), which is the output of the two-dimensional XR detector (3) that receives this, contains a large proportion of quantum noise. It becomes like this. This baby noise is integrated and reduced by the next-stage image processor (6). Therefore, in addition to displaying the image signal (7) on the display device (8), slight changes in the thickness of the object to be inspected (2) can be expressed as a difference in the brightness level.

Next, a case where the inspected object (2) is larger than the radiation trajectory (irradiation field) will be described. In this case, the object to be inspected (
In order to bring 2) into the radiation trajectory, the object to be inspected (2) is placed on the object to be inspected transport device (9) and is moved in a straight line. As a result, the following two methods are usually employed to improve the image quality of each frame of the transmitted X-ray image signal (1υ) detected by the two-dimensional X-ray detector (3).

(2) The object to be inspected (2) is moved step by step by the object to be inspected transport device (9). Then, the image processor (6) performs image integration for a certain period of time on the obtained transmission X-ray image signal (lO) in order to improve the image quality. During this time, the inspection object transport device (9) is stopped.

(The above details can be found in the paper "About X-ray fluoroscopy equipment for RUOG steel pipes" written by Akito Nakanishi and others published in the 157th Spring Conference Lecture Summary of Showa Box, Vol. 31, No. 2, No. 11J4-105). ) Similarly, 2) the object to be inspected (2) is moved by a small feed width by the object to be inspected transport device (9), and the image movement integral is calculated by the image processor (6). conduct. (The above details can be found, for example, in Japanese Unexamined Patent Publication No. 60-123.75.
It is disclosed in Publication No. 4. ) However, these two methods have the following problems.

That is, in the former case, X111i! performs image integration. In addition to the fluoroscopy time, it is necessary to add time for transporting the image over a distance, resulting in a problem that the throughput of the inspection time is reduced or the image contains a lot of quantum noise.

In the latter case, the Xi fluoroscopic inspection is performed without moving the object to be inspected (2) at a constant speed, which has the effect of reducing quantum noise without reducing throughput, but an image processor that performs image movement integration There is a problem that distortion occurs in the composite image output from (6).

This composite image distortion will be explained below.

In FIG. 5, the object to be inspected (2) travels in a straight line while crossing the X-ray fluxes (21), (22), and (23) emitted from the X-ray source (1). Here, the characters r4J are used as simulated defect signals on each inspection layer surface (24) of the object to be inspected (2).

(25) and (2B). And the object to be inspected (2)
Monitor the X-ray fluoroscopic image while moving the Figure 6(a)
An example of this X-ray fluoroscopic image is shown below. Image (27), (28)
, (29) are times (T1), (T2), and (T3), respectively.
) (T, <T2<T3).

Also, these images (27).

Figure 6(b) shows the screen composite images (30), (31), and (32) obtained by processing (28) and (29) with the image processor (6).
) as an example. As can be seen from this figure, as a result of moving and integrating the measurement screen, the screen composite image (3L) for the inspection layer surface (25) is undistorted, but the inspection layer surface (24), (26
), screen composite images (30) and (32) hs composition shift has occurred. However, each inspection layer surface (24)
, (25'), and (26) are actually different, but are shown with the same size in the figure. Such a synthesis deviation is caused by the following reason. That is, first, even if the inspection point is on the same inspection layer surface, the radiation trajectory (2
If each of (1) to (23) (each projection line) is different, the projection magnification ratio m on these trajectories will be different. For example, each radiation trajectory (2
L) ~ (23) Projection magnification ratio for K"25,211m2
s, 221m2s, 23, L21A+L2, B L2□+L22
8"°・"' L21A L2□e25.22 = L23A+ L23B m25.23: 23A is obtained. Here, L, L, L23A are the X-ray sources (1) on the radiation set trajectories (21) to (23).
) to the inspection layer surface (25), and LL21B1
Detection 3 on the radiation trajectory (21) to (23) as well as 22BI L+
B represents the distance from the aroma layer surface (25) to the two-dimensional XIm detector (3). In this way, the projection magnification ratio is the radiation locus (21
) to (23), so the inspection object transport device (9)
The object to be inspected (2) placed on is moving straight at a constant speed? Even if it travels, the projection speed on the two-dimensional X-ray detector surface differs even within the same inspection layer or between inspection layers, resulting in a composite shift.

As a method for preventing this synthetic distortion, for example, "Toshiba Review" Vol. 40, No. 12 (1985), No. 1028-1
There is something disclosed in the paper ``Recent non-destructive inspection systems using X-rays'' written by Masashi Fujii and others published on page 030. In this method, synthetic distortion is prevented by using a line sensor to detect transmitted X-rays from a non-inspection object traveling in a straight line, but unfortunately this method is not effective when the X-ray energy is low. However, there is a problem in that quantum noise increases as the value increases. In addition, when the object to be inspected has a circular pipe shape, image processing is performed using moving image integration to avoid generation of synthetic distortion.
Imaging Corporation (X-RAY IMA
GING CORPORATION)'s “Real Time” (September 21, 1982~
22nd) [Advantages of real-time radiation measurement (TI POTB)]
NTIALOF REAL-TIME RADIOGR
APHY) J. Although this method is effective in principle, in practice it is difficult to test thin test objects (5 to 40
(Tomo).

[Problem to be solved by the invention]

As explained above, in the conventional technology, when the object to be inspected is larger than the irradiation field of view and is moved in a straight line, integration processing is required to remove noise components from the transmitted X-ray image signal, and there are two methods. . Among these methods, the method of moving the object to be inspected for each step has problems in that the throughput of the inspection time decreases or the quantum noise becomes excessive. Another problem with the method of moving the object to be inspected at a constant speed is that distortion occurs in the composite image. Furthermore, there is a method of using a line sensor to remove this composite image distortion, but this method has the problem that quantum noise becomes harsh due to high energy. There is also a method of effectively performing moving image integration when the test food has a cylindrical shape, but there is a problem that it is not practical.

This invention was made in order to solve the problems of the prior art, and has a long X-ray transmission length (50 to 5 o
umm) Run the object to be inspected and apply high energy
When inspecting by irradiating with radiation (0.5 MeV to 2 (l MeV)), Xi
The purpose is to provide a fluoroscopic inspection device.

[Means to solve the problem]

The X-ray fluoroscopic inspection apparatus according to the present invention includes an XMA source that irradiates an object to be inspected with X-rays, and an X-ray beam extending from the above-mentioned IJ source to the object to be inspected. It has an inspection object transport device that rotates and travels in an arc shape on which an object is placed, and multiple rows of X-ray detection elements, and detects the X-rays that have passed through the inspection object and outputs a simple fluoroscopic image. a two-dimensional X-ray detector; and a two-dimensional X-ray detector;
An image processor receives a simple fluoroscopic image signal sent from the line detection signal every moment, integrates the movement of the image in accordance with the movement of the object to be inspected, and outputs an integral image signal, and the image processor outputs the integrated image signal. A display device for displaying the integrated image signal obtained is provided.

[Effect]

In this invention, since the movement locus of the object to be inspected has an arc shape, the mutual positions on a certain X-projection line within the object to be inspected can maintain a constant relationship no matter which projection line they are on. . Therefore, the projection magnification ratio becomes constant, and as a result, the moving speed of the projected images becomes the same. This makes it possible to remove screen synthesis distortion, and therefore, no matter where a defect is located on the object to be inspected, it can be accurately captured.

〔Example〕

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention, and the items denoted by symbols (1) to (8) and (1o) are the same as those in the conventional example shown in FIG. be. (
9 people) is a feature of this invention, and the object to be inspected (2)
This is an inspection object transport device that rotates and moves an object in an arc.

Next, the operation of the X-ray fluoroscopic inspection apparatus shown in FIG.
The figure and FIG. 3 will be explained.

In Figure 1, radiation (4) generated by an X-ray source (1) is irradiated onto an object to be inspected (2), and part of it is scattered and absorbed, but part of it is transmitted as it is, causing transmitted X-rays. (5)
become. This transmitted X-ray (5) is detected by a two-dimensional X-ray detector (3)
is detected and becomes an image signal (1υ). This image signal (
10) is sent to an image processor (6) and subjected to image integration.

In this case, the inspected object (2) is transferred to the inspected object transport device (9A
) and is rotated in an arc shape, so the image processor (6) integrates the image signal (10) as it moves in accordance with this rotation and synthesizes the image. This combined image signal (7) is sent to a display device (8) and displayed.

Here, FIG. 2 is a diagram showing how an image signal free from synthetic distortion is obtained by the X-ray fluoroscopic inspection apparatus of the present invention. The three inspection surfaces (51), (52), (53) are arranged in an arc around the X-ray source (1). Considering the projection magnification ratio m as in the conventional example, how K to remove the composite distortion will be explained as follows. Now, suppose there is an object to be projected onto the inspection layer surface (52),
Projection X-ray trajectory (54), (55).

(56) Projection magnification ratio m5□54+m5□55+m on (56)
5□, 56 is calculated as follows: L54A + L54B "52.54 = 54A (However, L54. is the distance from the inspection layer surface (52) to the surface of the two-dimensional X-ray detector (3), and L54A is the distance from the X-ray source (1 )
υ· represents the distance to the detection layer surface (52). ) (where, L is the distance from the inspection layer surface (52) to the surface of the two-dimensional X-ray 5B detector (3), and L55A is the distance from the X-ray source (1
) to the inspection layer surface (52). )L56
A + L56B "52.56: 58A (However, L56B is the distance from the inspection layer surface (62) to the surface of the two-dimensional X-ray detector (3), L is the distance from the X-ray source (1) 5
It represents the distance from 6mm to the inspection layer surface (52). ).

Here, the object to be inspected (2) is rotated in an arc around the X-ray source (1), so the projected X-ray trajectory (
54), (55), and (56), the value of L is constant. Therefore, the projection magnification ratio m remains constant while the object to be inspected (2) is rotating and traveling. Furthermore, on each of the inspection layer surfaces (51), (52), and (53),
Although the moving speed of the inspection object is different, two-dimensional X-ray detectors (3
) are the same, so the projection image is limited to the inspection layer surface (51).

(52), (5rj) can be maintained constant. Therefore, even after the movement integration by the image processor (6), as explained in the conventional example, that is, as shown in FIG. 6(b)
It is possible to prevent the occurrence of image synthesis distortion as shown in .

In the above embodiment, no special restrictions were placed on the two-dimensional X-ray detector (3), but as shown in FIG. They may be arranged dimensionally discretely. In this case, each X-ray detection element (
57), so that scattered X-rays generated within each X-ray detection element do not interfere with adjacent X-ray detection elements (absorption, etc.), each X-ray detection element is arranged at an integral multiple of the distance between each picture element, and each X-ray detection element is The gaps between the detection elements are filled with summer metal (62) or the like.

〔Effect of the invention〕

As explained above, this invention comprises an an inspection object conveyance device that rotates and travels in an arc shape while placing the inspection object;
a two-dimensional Xa detector having a plurality of rows of X-ray detection elements, which detects the X-rays transmitted through the object to be inspected and outputs a -C simple perspective image; Simple fluoroscopic image signals sent from the X-ray detector every moment are input,
The movement product of the image according to the movement of the object to be inspected. and an image processor that outputs an integral image signal, and an integral image signal sent out from this image processor. By providing a display device for displaying images, it is possible to obtain high-quality images with little image distortion.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the horizontal layer plane and its projection state in the X@fluoroscopic inspection apparatus shown in FIG. 1, and FIG. FIG. 4 is a plan view showing another example of a two-dimensional X-ray detector.
A schematic diagram showing a line perspective inspection device, FIG. 5 is a diagram showing the inspection layer surface and its projection state in the conventional example of FIG. 4, and FIG. 6 shows that synthetic distortion occurs in the image signal obtained with the conventional example of FIG. 4. It is a diagram showing the situation. In the figure, (1) is the X-ray source, (2) is the object to be inspected, and (3) is the
A dimensional X-ray detector, (6) &'s, an image processor, (8) a display device, and (9A) a detection object conveying device. In addition, the same reference numerals in the figures indicate the same or equivalent parts.
曾 my way to Teru ゛ 2 fig.

Claims (1)

[Claims] An X-ray source for irradiating X-rays onto an object to be internally inspected, and an X-ray source placed in an X-ray flux from the X-ray source in an arc shape with the X-ray source as the center. a two-dimensional X-ray detector having a plurality of rows of X-ray detection elements and outputting a simple fluoroscopic image by detecting X-rays transmitted through the inspection object; A simple fluoroscopic image signal sent from the two-dimensional X-ray detector every moment during the inspection of the object to be inspected is input, movement integration of the image is performed in accordance with the movement of the object to be inspected, and an integral image signal is output. An X-ray fluoroscopic inspection apparatus comprising a processor and a display device that displays an integral image signal sent from the image processor.