JPH0833449B2 - Radiation image receiving apparatus and radiation image receiving method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radiation image receiving apparatus and a radiation image receiving method for medical use, industrial use and the like.

2. Description of the Related Art Capturing an absorption image or a reflection image of radiation by an object to be measured while moving an object to be measured (hereinafter referred to as an object to be measured) is widely used in the medical and industrial fields.

This irradiates the measured object that moves relative to the radiation detector with radiation, detects changes in absorption and reflection of the radiation by the measured object with the radiation detector, and inspects and analyzes the measured object. It is a thing.

In this image receiving method, in the industrial nondestructive inspection, the X-ray source and the radiation detector are arranged with the object to be measured placed on the conveyor line sandwiched between them, and image measurement is performed at a constant cycle to measure the object to be measured. I am imaging. A radiation detector or a radiation detector is generally used.

In recent years, the technology has been remarkably improved in radiation image reception, and a radiation detector with high resolution has been developed. For example, a method has been developed in which semiconductor detectors are arranged in an array, radiation quanta are detected on a surface, and a coefficient value of the signal is used as a pixel density to display an image (Japanese Patent Laid-Open No. 59-100885). . According to this method, the dynamic range of each detection element is significantly improved, so that a highly accurate image can be obtained.

Furthermore, the image date processing enables inspection and analysis such as chemical composition and elemental analysis of the measured object.

A conventional radiation image receiving apparatus and radiation image receiving method will be described below.

FIG. 7 is a configuration diagram for explaining a conventional radiation image receiving apparatus and radiation image receiving method. In the figure, an example using X-rays as radiation will be described.

In the figure, 3 is an object to be measured, 3a is a low absorption material portion, 3b
Is a high absorption material part, and 4 is a radiation detector. In order to clarify the contrast between the position of the radiation detector 4 and the output signal, it is assumed that the measured object 3 has a low-absorption material portion 3a and a high-absorption material portion 3b that are clearly separated. Further, in order to make it easy to compare the position of the radiation detector 4 and the output signal, the measured object 3
Is fixed and the radiation detector 4 is moved, the horizontal axis shows the position of the radiation detector 4, and the vertical axis shows the output signal of the radiation detector 4.

In such a configuration, when the radiation detector 4 is at the position shown in FIG. 7, the irradiation X-rays directly enter the radiation detector 4, and the output signal becomes S ₁ . Next, the radiation detector 4 moves rightward toward the paper surface, and when the radiation detector 4 reaches the edge of the measured object, the output starts to decrease. Radiation detector 4
Is completely entered into the low-absorption material part 3a in the measured object 3, the output signal becomes S ₂ . When the radiation detector 4 further moves to the right and reaches the high absorption material portion 3b, the output signal starts to decrease, and when the radiation detector 4 completely enters the high absorption material portion 3b, the output signal is the minimum value S. It becomes ₃ .

However, since the radiation detector is fixed in the above-mentioned conventional configuration, the target area per unit element is enlarged due to the movement of the measured object, resulting in blurring on the image and measurement error. It was. For this reason, in the precise analysis of a minute portion, the step feed for temporarily stopping the measured object 3 is performed, but in the device used for medical treatment, the patient bed is large and the industrial use is large. Even in the equipment used for, the step feed is difficult because the inertia of the conveyor is large, and there is a problem that high-precision measurement is impossible.

The present invention is to solve the above-mentioned conventional problems, and in receiving an image of a moving object, the blur on the image of the pixel end portion caused by the positional deviation between the radiation detector and the measured object is minimized, and It is an object of the present invention to provide a radiation image receiving device that can obtain highly accurate performance even with precise analysis of various parts.

Means for Solving the Problems In order to achieve this object, a radiation image receiving apparatus according to the present invention is a radiation source arranged in a plane perpendicular to a traveling direction of a moving object to be measured and sandwiching the object to be measured. In the radiation image receiving device including the radiation detector and the radiation detector, the radiation detector moves in the same direction as the object to be measured during image measurement to obtain image information.

With this configuration, the radiation detector is moved in the same direction as the object to be measured during image measurement, so that the target area per unit element is substantially the size of one unit element, and the object to be measured is It is possible to minimize the occurrence of an error due to the movement of.

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

FIG. 1 is a configuration diagram of a radiation image receiving apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram showing an embodiment of a radiation detector used in the radiation image receiving apparatus of the present invention, and FIG. FIG. 4 is a configuration diagram showing another embodiment of the radiation detector used in the radiation image receiving apparatus, FIG. 4 is an operation diagram showing an example of the operation of the radiation detector used in the radiation image receiving apparatus of the present invention, and FIG. Operation diagrams showing another example of the operation of the detector, and FIGS. 6 (a) to 6 (c) are characteristic diagrams showing the relationship between the radiation detector position and the output signal.

In these figures, 1 is a radiation source, 2 is an irradiation diaphragm,
3 is a measured object, 4 is a radiation detector, 5 is a measured object 3
A moving table that mounts and moves, 6 is a driving body that drives the moving table, 7 is a case that houses the radiation detector 4, 8 is a radiation detector peripheral circuit section, 9 is a radiation detector fixing table, and 10 is radiation detection A drive source, 11 a support, 12 a signal cable, 13 a drive controller for controlling the radiation detector 4, 14 input / output terminals, and 15 a lattice structure.

The operation of the radiation image receiving apparatus configured as described above will be described below.

FIG. 1 shows an example in which an X-ray source is used as the radiation source 1, but the same applies to visible light, infrared light, synchrotron radiation, beta rays, gamma rays, and neutron rays. From the X-rays emitted from the radiation source 1, only the necessary X-rays are extracted by the irradiation diaphragm 2. This X-ray passes through the measured object 3 and is detected by the radiation detector 4. The measured object 3 is placed on the moving table 5 and moves in the left-right direction. On the other hand, the radiation detector 4 is housed in the case 7 together with the radiation detector peripheral circuit 8. The case 7 is installed on the radiation detector fixing base 9 and connected to the radiation detector driving source 10, and the radiation detector fixing base 9 is installed in a movable state on the support base 11. The radiation source 1 may be fixed, but when the movement range of the measured object 3 is long, it needs to be moved together with the radiation detector 4. A conveyor belt or the like is used as the moving table 5.

When the one-dimensional line sensor in which the detecting elements are arranged in one dimension is used as the radiation detector 4, the one-dimensional line sensor is installed vertically to the moving direction of the measured object 3 and scans and moves line by line. Performs two-dimensional image measurement. When a two-dimensional surface sensor in which detection elements are arranged in a plane is used as the radiation detector 4, the radiation detector 4 is moved by one pitch of the pixels forming the two-dimensional surface sensor to perform two-dimensional image measurement. To do.

FIG. 2 shows an embodiment of the radiation detector used in the radiation image receiving apparatus of the present invention. However, since only the radiation detector 4 is configured to move back and forth by the radiation detector driving source 10, the apparatus Can be downsized. An external signal is supplied from the input / output terminal 14, and the signal enters the radiation detector driving source 10 from the drive control unit 13 and controls the radiation detector 4. On the other hand, the output from the radiation detector 4 is guided to the radiation detector peripheral circuit 8 by the signal cable 12 and taken out through the input / output terminal 14 to the outside.

FIG. 3 shows another embodiment of the radiation detector used in the radiation image receiving apparatus of the present invention. A grid-like structure 15 for shielding radiation is installed on the front surface of the radiation detector 4 to form a grid-like structure. Only 15 is configured to be moved back and forth by the radiation detector driving source 10. Therefore, not only can the device be miniaturized, but since the radiation detector 4 does not move, the wiring of the electric system such as the signal cable 12 can be fixed, and a very reliable radiation detector can be realized. In this case, the length of the single pixel of the radiation detector 4 with respect to the moving direction is obtained by adding the distance over which the image moves on the radiation detector 4 in one image measurement period and the aperture of the lattice-like structure that shields the radiation. Greater than length.

In the radiation receiving apparatus of the present invention, the radiation detector 4
Further, the movement of the lattice structure 15 is important. As shown in FIG. 4, the position of the measured object 3 moves with time, but the radiation detector 4 moves in the same manner as the measured object 3 during the image measurement period, and when returning, at a higher speed than when moving forward. By moving, the number of image measurements can be increased. Further, as shown in FIG. 5, the radiation detector 4 is moved forward and stopped or moved forward at a low speed along a movement of the measured object 3 for a fixed cycle or a fixed distance, so that the measured object 3 moving at a high speed. It is possible to measure with high accuracy.

The moving distance of the radiation detector 4 is a moving distance corresponding to one pixel of the measured object 3 per one image measuring period, and is 1 mm or less in a high-definition image when X-rays are used, and on the solid-state image sensor. In the method of forming an optical image with a lens, the pixel pitch of the solid-state image sensor is about 10 μm, and the driving device of the radiation detector 4 is also very small.

The relationship between the radiation detector position and the output signal in the above-described embodiment is as shown in FIG. In this case, the object 3 to be measured is composed of the low-absorption material portion 3a and the high-absorption material portion 3b as an example. First, the output signal in the ideal case should clearly appear corresponding to each part of the measured object 3, as shown in FIG. 6 (a). On the other hand, in the conventional example shown in FIG. 1B, the output signal is broken and the image data is very bad, and highly accurate measurement cannot be performed. The output signal from the radiation image receiving apparatus of the present invention is shown in FIG. 6 (c), but the contrast is good, although it deviates from the slightly ideal case (shown by the chain double-dashed line) in the high-absorption material portion 3b. Can be expected.

Although the present invention has been described above by applying it to a radiation transmission image, the same effect can be obtained even in capturing and reading a normal optical image.

As described above, according to the present invention, since the target area per unit element is fixed during the image measurement period, the resolution per pixel can be substantially improved, and the error due to the movement of the measured object is generated. It is possible to realize an excellent radiation receiving apparatus and radiation receiving method capable of minimizing the above. For this reason, highly accurate image measurement becomes possible, and improvement in analysis accuracy of minute images such as X-ray images and optical images can be realized, which greatly contributes to medical measurement and industrial measurement.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radiation image receiving apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram showing an embodiment of a radiation detector used in the radiation image receiving apparatus of the present invention, and FIG. FIG. 4 is a configuration diagram showing another embodiment of the radiation detector used in the radiation image receiving apparatus, FIG. 4 is an operation diagram showing an example of the operation of the radiation detector used in the radiation image receiving apparatus of the present invention, and FIG. Operation diagram showing another example of the operation of the detector, FIG. 6 (a)
(C) is a characteristic diagram showing the relationship between the radiation detector position and the output signal, and FIG. 7 is a configuration diagram for explaining the conventional radiation image receiving apparatus and radiation image receiving method. 1 ... Radiation source, 3 ... Object to be measured (object to be measured), 4 ... Radiation detector, 5 ... Mobile stand.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuro Oduchi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-2-73185 (JP, A)

Claims (4)

[Claims] 1. A radiation source, a radiation detector provided to face the radiation source, a space sandwiched between the radiation source and the radiation detector, and an object to be measured is mounted and moved in a fixed direction. A radiation image receiving apparatus provided with a movable table, wherein the radiation detector has a mechanism for reciprocating a distance corresponding to one pixel in the same direction as the object. 2. The radiation image receiving apparatus according to claim 1, wherein the radiation detector comprises radiation detecting elements arranged in a plane or in a straight line. 3. The radiation detector has a lattice-like structure for shielding radiation on the front surface of its radiation incident surface, and the lattice-like structure reciprocates a distance corresponding to one pixel in the same direction as the object to be measured. The radiation receiving apparatus according to claim 1 or 2, wherein 4. A radiation source, a radiation detector provided so as to face the radiation source, and a movable table which is located between the radiation source and the radiation detector and which carries an object to be measured and moves in a fixed direction. A radiation image receiving method in which a radiation image receiving device is used, and a radiation detector is moved back and forth in a direction corresponding to one pixel in the same direction as an object during image measurement.