KR19980083488A - Radiography Imaging Method and System - Google Patents

Abstract

A convergence type X-ray generator that generates an X-ray including an X-ray bundle that converges at a predetermined position, and faces the convergence type X-ray generator; A subject having an X-ray detector arranged to sandwich the subject, a pinhole member disposed between the subject and the X-ray detector, and a signal processor configured to signal-process an output signal from the X-ray detector; System for X-ray imaging.

Description

Radiography Imaging Method and System

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method and system for radiographic imaging of a subject of a living or non-living organism, and more particularly, to a radiographic imaging method and system that can be preferably applied to a tomographic system.

As a typical method of a radiographic image capturing method and system, an X-ray image capturing method and system irradiates X-rays from an X-ray source by a subject, and transmits X-rays passing through the subject to X-ray film, X- It burns with a line TV unit or the like. An X-ray image imaged by an X-ray film, an X-ray TV unit, or the like is a transmissive X-ray image (simple transmission X-ray image) displayed by an X-ray film or a TV monitor or a single layer shown by a TV monitor. There is a burn.

Here, the tomographic images include tomographic images photographed by a CAT (Computed-Assisted Tomography) method and tomographic images photographed by a direct tomography method. The former method is realized by the X-ray CAT Scanner System, and the latter method is called direct tomography, and is known as Laminagraphy or Planigraphy.

In the present invention, the problems to be solved in the radiographic image capturing method and system for acquiring a transmission X-ray image will be described sequentially.

First, in order to obtain a clear X-ray image, it is necessary that the focal dimension of the X-ray tube is small. However, since the thermal load of the target portion of the anode of the X-ray tube is limited, the lower limit of the focal length is defined by itself. In other words, if the focal dimension is made small, thermal degradation of the target cannot be avoided, and eventually, the desired focal dimension for obtaining a clear X-ray image cannot be obtained. In addition, for a large subject, even if the X-ray detector does not have a large area, the entire large subject cannot be photographed at once. Large area X-ray detectors include photographic films, which also have limitations, and are practically limited to several centimeters in electronic form and several centimeters in vacuum form. Therefore, a photographing method that can photograph a large subject at a time is desired.

Secondly, the farther away from the X-ray tube, the larger the field of view is obtained, and the larger subject can be photographed. However, the further away from the X-ray tube, the weaker the X-ray intensity, so that the X-ray detector cannot be moved beyond the practicality of the X-ray detector. When a plurality of pairs of X-ray tubes and X-ray detectors face each other, that is, juxtaposed, the overall field of view becomes large, but dead space, which is a dead space of the photographing field, is not suitable. As described above, it is difficult to obtain a large field of view by the conventional method.

Third, there is a known phenomenon in which harmful scattering X-rays are applied to detectors such as X-ray films, X-ray detectors, X-ray vidicon plates, CCD image sensors, image intensifiers, and the like. This phenomenon is a factor that impairs the sharpness of the image.

Fourth, if the subject is a human body, there is no effective means for reducing the output of the X-ray tube to reduce the exposure, but the output is not reduced to less than the output required to obtain the X-ray image. Since X-rays are harmful to humans, it is desirable to reduce the maximum exposure.

Next, the problems to be solved by the radiographic method and system for acquiring tomographic images will be described sequentially.

First, it is required to shorten the tomographic imaging time. That is, in imaging a tomography image, the highest speed of imaging is required for the heart showing the fastest movement in the body, and the stretching period of the human heart is about 1 second, and the image display when the continuous tomography image is required. It is desirable to reduce the speed to about one tenth of a second of heartbeat. In addition, when imaging a tomographic image for industrial purposes, it is preferable that it is about 1/100 second faster, but it is fully real time, ie, the calculation time for reproducing is zero. This is because industrial products are transported at high speed, unlike the human body, and continuously and continuously.

Secondly, it is required to obtain a tomographic image that is clear and has no unnecessary scattered light and that is free of false images. In other words, tomographic imaging by the X-ray CAT Scanner System may in principle cause false images and incomplete images, which may damage the high-precision inspection.

Third, it is required to obtain a plurality of tomographic images simultaneously at high speed.

Fourth, to obtain a three-dimensional tomographic image is required.

Fifth, there is a need to provide an imaging method and system capable of tomographic imaging and tomographic inspection of a continuous subject or a semi-continuous subject.

Sixth, it is required to provide an imaging method and system with a small exposure amount of a subject.

1 is a block diagram of a radiographic imaging system of the present invention.

2A-C show the principle of direct tomography.

3A-3E show an X-ray generator.

4 is a view showing a convergence type two-dimensional X-ray generator of the present invention.

5 is a cross-sectional view taken along the line V-V in FIG.

6 and 7 are cross-sectional views showing another example of the converging two-dimensional X-ray generator of the present invention.

8 is a view showing another example of the converging two-dimensional X-ray generator of the present invention.

9 is a view showing the relationship between the converging two-dimensional X-ray generator, the X-ray detector and the pinhole member of the present invention.

10 is a view showing another example of the converging two-dimensional X-ray generator of the present invention.

11A to 11C are diagrams showing the relationship between the X-ray generator, the X-ray detector, the pinhole member, and the subject in the present invention.

12 is a view showing the relationship between the X-ray generator, the X-ray detector, the pinhole member and the subject in the present invention.

13A to 13C show a method of driving an area type CCD image sensor in the present invention.

14 and 15 are views showing the relationship between the X-ray generation and the pinhole member including the X-ray detector and the slit plate and the subject in the present invention;

FIG. 16 is a view showing an embodiment in which a plurality of X-ray generators are arranged in the present invention. FIG.

17 and 18 show a method of capturing a plurality of tomographic images in the present invention.

Fig. 19 is a diagram showing a method for imaging a tomographic image in the present invention.

20 is a block diagram showing a specific example of a signal processing system according to the present invention;

21 and 22 illustrate the function of an alignment member in the present invention.

23 is a plan view of an alignment member in the present invention.

24, 25, 26 and 27 illustrate the function of the alignment member in the present invention.

FIG. 28 illustrates the function of a high pass filter in the present invention. FIG.

Fig. 29 is a diagram showing an example of a bio-monoscopic imaging device of the present invention.

30 shows a detailed example of the X-ray sensor unit of FIG.

31 is a view showing a defect inspection system of the steel slab in the present invention.

FIG. 32 shows the steel slab in FIG. 31. FIG.

FIG. 33 is a view showing the relationship between the subject and the pinhole member including the X-ray generator, the X-ray detector and the slit plate in FIG.

FIG. 31 is a characteristic diagram showing a method for determining a defect in FIG.

FIG. 35 shows a defect inspection system for die-cast castings in the present invention. FIG.

The present invention is configured as follows to solve the above problems.

That is, the system of the present invention opposes a convergence type radiation generating unit for generating radiation including a bundle of radiation converging at a predetermined position, and confronts the subject with the convergence type radiation generating unit. And a pinhole member disposed between the arranged radiation detector, the subject, and the radiation detector, and a signal processor for signal processing an output signal from the radiation detector.

The system further includes a pair of the converging radiation generating unit, the pinhole member and the radiation detecting unit, and moving means for relatively moving the subject. The radiation detection unit of the system includes an accumulation type two-dimensional radiation detector, wherein the accumulation type two-dimensional radiation detector moves the accumulated charge at a moving speed corresponding to a relative moving speed between the subject and the radiation detection unit. It has a means for making it.

The converging radiation generator of the system includes a plurality of converging radiation generators arranged in parallel.

Means for shifting the accumulating charge CCD and the accumulating charge of the movable adding CCD to move and add accumulated charges at a moving speed corresponding to a relative moving speed of a specific tomographic plane in the subject and the radiation detecting part of the system; It is provided.

The signal processing system of the system is provided with a high pass filter.

The pinhole member of the system has a function that the convergence and divergence angle of the radiation is 50 ° C or more. The pinhole member and the radiation detector of the system are disposed in close proximity. The pinhole member of the system includes a pinhole plate and a silt plate.

An alignment member is further provided between the converging radiation generating unit of the system and the subject to suppress an amount of radiation that does not enter the radiation detecting unit from irradiating the subject. The alignment member of the system has first and second alignment plates arranged in parallel, the plates having a plurality of holes formed therein, and a second alignment. The center coordinate of the hole of the plate is set to proportionally reduce or proportionately enlarge the center coordinate of the hole of the first alignment plate.

In addition, in order to solve the above problems, the method of the present invention includes the steps of generating radiation to converge at a predetermined position, the step of irradiating the generated radiation to the subject, and detecting the transmitted radiation through the subject through the pinhole member; And signal processing the detected signal.

Hereinafter will be described the operation and effect of the present invention.

According to the present invention, the X-ray generating unit 101 and the X-ray detecting unit 102 are disposed to face each other, as shown in FIG. 1, and the object 100 and the X-ray detecting unit 102 are disposed. An image pickup system in which a pinhole member 104 serving as a space coupler is placed between and. In this system, the subject 100 and the X-ray detector 102 are moved relative to each other to directly perform tomographic imaging. This relative motion is achieved by actually moving the subject 100 and the X-ray detector 102 and also by the electrical control of the X-ray detector 102.

The system control unit 105 controls the movement of the bed or the like on which the subject 100 is placed, the control of the X-ray generating unit 101, the movement control and the detection control of the X-ray detecting unit 102, and the detection unit 102. Control of the signal processing unit 106 for signal processing the output and the like. The output image of the signal processing unit 106 is displayed on the display unit 107.

Prior to the description of the embodiments of the present invention, the principle of the X-ray direct tomography imaging method using the imaging system will be described with reference to A-C in FIG.

2A to 2C, the X-ray tube 103 radiated from the X-ray tube 101 penetrates the subject 100 and reaches the S point on the detection unit 102 which is an accumulation image sensor. When the moving speed of the specific tomography layer SL ₁ of the subject 100 is equal to the moving speed of the detector 102, the positional relationship between the X-ray tube 101, the subject 100, and the detector 102 is equal to the clockwise direction. Proceed with FIG. 2A-FIG. 2B-FIG. 2C.

No. 2A - is a specific single-walled any point on the SL ₁ in Fig. 2C to the A. In FIG. 2A, the intensity of X-rays passing through the point A is accumulated at the point S on the detection unit 102. FIG. Let this be X ₁ . For simplicity, if the representative point of the X-ray 103 is B, E, A, then X ₁ = B + A + E. Equally the second is a X ₂ = C + A + F B in the FIG. Similarly, in FIG. 2C, X ₃ = D + A + G. The detection unit 102 is an accumulation type image sensor, and the accumulated X-ray intensity is (X-ray intensity) = (X ₁ ) + (X ₂ ) + (X ₃ ). Thus, (X-ray intensity) = (B + A + E) + (C + A + F) + (D + A + G) = (A + A + A) + (B + C + D) + ( E + F + G) = (3A) + (B + C + D) + (E + F + G).

The above equation is sufficient to obtain the principle concept of the direct tomography imaging method, but lacks mathematical rigor. Strictly apply the absorption coefficient of the material of each point U in the formula II ₀ · EXP (-UT) of X- ray absorption A, B, C, D ... . Where I is the X-ray intensity after transmission, I ₀ is the transmissive X-ray intensity, and T is the thickness of the subject 100.

In the X-ray intensity = (3A) + (B + C + D) + (E + F + G), A is highlighted and (B + C + D) is viewed as the averaged background (background value). If possible, then (X-ray intensity) = (3A emphasis) + (averaged background). If (averaged background) is (completely averaged background), the human vision is (X-ray intensity) = (3A emphasis) = (A + A + A). This is the principle of direct tomography.

Next, each element of the present invention will be described. The accumulation type image sensor, which is a detection unit used in the present invention, is a kind of X-ray detector, in which a trace is accumulated and added unless the trace of X-ray energy acting on the sensor is actively disappeared or not actively transmitted. Sensor. Specific examples of the accumulation type image sensor include a photographic film, a CCD image sensor, an optical image pickup plate, and the like.

The X-ray generating unit includes an X-ray including a divergent X-ray source in the form of emitting conventional X-rays around and X-ray bundles that converge at certain specific positions in the present invention. There is a converging type X-ray source.

Figures 3A-3E show various sources of X-rays.

Part 3A turn and zero dimensional X- crew having a X- ray generating body (110 ₁₎ of the conventional technology, zero-dimensional (point), a diverging (發散型) X- crew.

FIG. 3B is a one-dimensional X-ray source holding a one-dimensional X-ray generator (line) 110 ₂ , and FIG. 3C is a two-dimensional holding a two-dimensional X-ray generator (plane) 110 ₃ . X-ray source, 3D diagram is a three-dimensional X-ray source having a three-dimensional X-ray generator (curve) (110 ₄ ), and 3E is a three-dimensional X-ray generator (circular body) ( 110 ₅ ) are three-dimensional X-ray sources, which are convergence type X-ray sources. In the present invention, a convergent X-ray source can be used as the X-ray generator.

4 and 5 are schematic diagrams of a converging X-ray generator that can be used in the present invention. The X-ray generator is a reflective X-ray generator, and the two cathodes 121 housed in the vacuum vessel 120 generate heat electrons by heating the power supplied from the cathode power source 122 through the electrical wiring. do. The hot electrons are accelerated by an electric field caused by a high voltage supplied from the positive electrode power source 123 to the positive electrode 124 and collide with the positive electrode 124 to generate fresh wire. In FIG. 4, the anode 124 also serves as a target. Some of the generated X-rays pass through the X-ray transmission window 125 and the pinhole member 126.

6 is a transmissive X-ray generator in which the positional relationship between the three cathodes 121 and the anodes 124 is opposite to that of FIG. 7 is a transmission X-ray generator in which the anode 124 is disposed outside the X-ray transmission window 125.

As shown in FIG. 8, by placing a pinhole member between the X-ray generator 130 and the X-ray detector 102 according to the example of FIGS. 4-7, the viewing area of the X-ray detector 102 is At least the subject 100 can be imaged X-ray in a large field of view.

In addition, as shown in FIG. 9, a plurality of pairs of the pinhole members 104 and the X-ray detection unit 102 can be arranged side by side, and imaging of a large field of view can be performed. In addition, in the examples of FIGS. 8 and 9, dead space in the photographing field can be eliminated.

In FIG. 10, the hot electrons emitted from the cathode 121 in the vacuum vessel 120 are accelerated toward the anode and collide with the anode 124A. The collision energy is converted into X-ray energy to generate X-rays. The rate at which the surface shape of the anode 124A passes through the X-ray pinhole member 104 generated in the case of a parabolic surface having the pinhole member 104 as a focal point is larger than that of the other shape of the anode 124A. . Parabola has the property of reflecting parallel rays to its focal point. It is known that the relationship between the collision angle of the hot electrons and the main angle of the generated X-rays is equivalent to the reflection of light rays, and as shown in FIG. 10, the ratio of X-rays passing through the pinhole member 104 is large.

Here, the main angle refers to the angle formed by most of the generated X-rays. In reality, the cost of grinding and molding the parabolic surface is expensive, and is substituted into a spherical surface that is easy to mold. It is natural that this spherical surface should be as close to a paraboloid as possible, and is called an approximate parabolic surface in the present invention. One example of an anode formed of an approximate parabolic surface is that the material is glass, and the surface is formed by tungsten spattering or spraying on the surface. In another example, the material is aluminum, which is tantalum deposition or tungsten deposition on the surface.

11A to 11C and 12, the X-ray detector 102 is assumed to travel at the same speed as the subject 100. FIG. As shown in FIGS. 11A to 11B to 11C, a simple transmission image of the subject 100 is formed on the X-ray detector 102 by the X-rays irradiated from the X-ray generator 103. FIG. The X-ray detection unit 102 of FIGS. 11A-11C is a two-dimensional detector, a specific example of which is a photographic film. In order to obtain a clear X-ray image, it is necessary to have a small focal dimension. If the hole diameter of the pinhole member 104 is arbitrarily reduced in FIGS. 11A to 11C, a clear X-ray image can be obtained. This is because the pinhole member corresponds to the size of the focal dimension of the X-ray tube.

11A to 11C, the X-ray generating unit 130 and the pinhole member 104 are stopped, and the subject 100 and the X-ray detecting unit 102 are moving. For example, the subject 100 And the X-ray detector 102 and the X-ray generator 130 and the pinhole member 104 are moved to obtain an image. Moreover, everyone may be moving.

11A to 11C, the X-ray detection unit 102 may be an area CCD image sensor. In addition, instead of tomographic imaging, in a simple transmission image imaging, a plurality of pinholes are drilled in the pinhole member 104 to increase a predetermined amount of X-rays by the area type CCD imaging sensor 200 as the X-ray detection unit. You may juxtapose many slit boards. In other words, if the hole diameter of the pinhole member is reduced to obtain a smaller focal point, which is a smaller equivalent point, the amount of X-ray passage decreases, so that a multi-layered split-hole pinhole member in which multiple pairs of pinhole members and slit are juxtaposed is used.

Next, with reference to FIG. 12, the electrical control of the X-ray detection unit 102 for direct tomographic imaging, and in detail, the relationship between the tomographic plane of the subject and the CCD device (area type CCD image sensor) will be described.

In FIG. 12, an X-ray generating unit (not shown), a pinhole, and a CCD device are provided, and the subject moves in the direction of the arrow shown. The image pickup target is the tomographic layer SL ₁ -SL ₄ of the subject.

In FIG. 12, when the field of view of the same area with respect to the single-layer SL ₁ -SL ₄ is viewed around the pinhole, the relative moving angle (relative velocity) with respect to the CCD device of the single layer SL ₁ -SL ₄ is the lowest single layer SL. ₄ viewing angle R 'is the largest, the viewing angle for a single layer of the uppermost layer SL ₁ R ₁ is the smallest on. In other words, in the pinhole, the monolayer SL has the fastest velocity in the monolayer SL ₄ and the slowest in the monolayer SL ₁ . Therefore, the moving speed of the phase on the CCD device is the fastest in the single layer SL ₄ , and the slowest in the single layer SL ₁ . Here, the image on the CCD device is an image in which the monolayer SL is projected onto the CCD device through the pinhole.

The X-ray generator irradiates the X-rays to the subject, and the apparent moving speed of the tomography layer SL ₁ (moving from q to p) and the scanning speed of the CCD device corresponding to the tomography layer SL ₁ (from q to p) You can take a single-layer SL ₁ of the apparent match even by scanning the CCD device subjects the moving speed).

The same and the number of shooting the scanning speed of the CCD device apparently consistent sikimeuroseo single layer SL ₂ corresponding to the moving speed and the single-layer SL ₂ the apparent single-layer SL _2, corresponding to the movement speed and the single-layer SL ₃ the apparent single-layer SL ₃ A single layer SL ₃ can be photographed by apparently matching the scanning speed of the CCD device to be measured, and the apparent moving speed of the single layer SL ₄ (speed moving from Q 'to P') and the scanning of the CCD device corresponding to the single layer SL ₄ are obtained. A single layer SL ₄ can be photographed by scanning of this CCD device by apparently matching the speed (moving speed from q 'to p').

This example uses a single CCD device and is a method of photographing a tomography that is arbitrarily determined by the scanning speed of the CCD device. However, a plurality of pairs of CCD devices and pinholes are arranged in accordance with the moving direction of the subject, and by varying the scanning speed of each CCD device, a plurality of tomographic images corresponding to different scanning speeds of the plurality of CCD devices can be collectively taken. have.

Examples of FIG. 17, FIG. 29, FIG. 31, FIG. 33, and FIG. 35 described later specify a method of collectively photographing such a plurality of tomography.

Next, a driving method of the area CCD image sensor 200 will be described with reference to FIGS. 13A to 13C.

That is, the present driving method moves electrons generated in the NxM pixels of the CCD to the VD direction (the vertical driving direction to the N direction in the drawing) as shown in FIGS. 13A to 13C. In addition, it is a driving method for accumulating and adding charges in the VD direction.

In the present specification, the area CCD to which the driving method is applied is omitted as the charge-adding CCD 300 by omitting the accumulated charge transfer addition-type CCD. In the simple transmission image photographing in FIGS. 11A to 11C and 14, the area CCD image sensor 200 is an example of moving at the same speed as the subject. In addition, when the mobile addition CCD 300 is applied, the mobile addition CCD 300 can be stopped as shown in FIG. In other words, the accumulated charge moves instead of the CCD.

The imaging method and apparatus of the present invention are not affected by scattering lines by the pinhole member 104. That is, the scattering line is removed by the pinhole member 104. In addition, the reduction in the focus dimension can be achieved by reducing the hole diameter of the pinhole member. As the hole diameter of the pinhole member 104 decreases, the amount of X-rays incident on the X-ray detector decreases, and a high-sensitivity X-ray detector may be required to obtain an X-ray image. In this case, a moving addition CCD which is a high sensitivity detector is used. When an image intensifier, which is a radiation sensitivity doubling element, is incorporated into a CCD, it becomes more sensitive, that is, the hole diameter of the pinhole member can be reduced.

In the direct tomography imaging system, the sharpness of the image is improved by increasing the angle ANG shown in FIG. As shown in FIG. 16, when the plurality of X-ray generating units 101 are arranged side by side in an arc shape, for example, it is possible to increase the effective procedure and the divergence angle (corresponding to the angle ANG) with respect to the pinhole member 104. . When the angle was 50 degrees or more as a result of the experiment, a good tomographic image was obtained. In addition, the illustrated arrow indicates the moving direction of the subject 100.

FIG. 17 shows a situation where an image is taken of tomographic layer SL ₁ -SL ₅ to be imagined at the same time. Equivalent (等價of five pinhole member (104 ₁ -104 ₅₎ and five storage type X- ray detector (300 ₁ -300 ₅₎ placed side by side to a storage type X- ray detector (300 ₁ -300 ₅₎的) Is made equal to the equivalent moving speed of each tomography of the subject 100. For example, the equivalent moving speed of the stacked type X-ray detector 300 ₁ is made equal to the equivalent moving speed of the single layer SL _{1, and} the equivalent moving speed of the stacked type X-ray detector 300 ₂ is set to the single layer SL ₂ . Equal to the equivalent movement speed. In this way, the image of each single layer SL ₁ -SL ₅ is made possible at the same time image capture. In addition, the arrow shown indicates the moving direction of the subject 100.

18, the accumulation type X-ray detector shows the case of the moving addition CCD 300. As shown in FIG. An example of the pair of pinhole members 104 and the moving addition CCD 300 is shown in FIG. In FIG. 18, the equivalent moving speed of the accumulated charges is delayed in order of faults SL _A , SL _B , SL _C. When the equivalent moving speed of the accumulated charge for example, equalize the moving speed of the single-layer SL _B it is obtained tomographic image of the single-layer SL _B. To obtain a plurality of tomographic images simultaneously at a high speed, for example, the subject 100 may be moved at high speed, or the pair of the pinhole member 104 and the accumulated X-ray detectors 200 and 300 may be moved at high speed. In addition, the arrow shown indicates the moving direction of the subject 100.

In FIG. 19, the moving direction of the accumulation type X-ray detector 200 may be any one of up, down, or right angle to the ground when the subject 100 is stationary. In addition, when the subject 100 is moving, if the accumulation type X-ray detector is the moving addition CCD 300, the X-ray detector 102 may be stopped.

The subject in this invention is demonstrated. That is, in industrial products, many of the same shape are produced and are often conveyed continuously along the production process line. As an example, diecast castings are mentioned. In many cases, tomographic inspection requires tomographic inspection. In the present invention, since the calculation time for generating the tomographic image is unnecessary like the CT method, the tomography is imaged in real time. Real-time tomography inspection is possible for continuous conveyance such as traveling sheet material or continuously conveyed continuously (abbreviated as semi-continuous), although there is a gap like the die-cast casting product described above. In the tomography inspection, it is determined whether it is normal or abnormal compared with the tomographic image of the product to be inspected based on the normal tomographic image of the normal product.

The above-described determination is made by the signal processing system formed from the subject image memory 401, the reference image memory 402, the image comparison section 403, and the abnormal part extraction circuit 404, which introduce the image data from the detector as shown in FIG. You can do In a tomographic image of a subject irradiated with X-rays, there is a subject that needs to be considered so that unnecessary X-rays are not irradiated on the subject. One example is when the subject is a human body, and in order to minimize the effects of radiation disturbances, it is required to minimize unnecessary X-ray irradiation.

In FIG. 21, a solid line of radiation irradiated from the two- or three-dimensional radiation source 101 is a necessary radiation 103A, and passes through the object 100 and the pinhole member 104 to store the accumulated image sensor ( 200) and is necessary to obtain a tomographic image. On the other hand, what is shown by the broken line is unnecessary X-ray 103B, and it is unnecessary to obtain a tomographic image.

In FIG. 22, an X-ray alignment member 500 is provided between the two-dimensional or three-dimensional X-ray generating source 101 and the subject 100. FIG. The X-ray alignment member 500 passes the necessary radiation 103A through the pinhole member 104 to reach the accumulation type image sensor 200 to block unnecessary X-ray 103B.

23 is a plan view of the X-ray alignment member 500, and a plurality of holes 500A are provided.

24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 23, and the X-ray alignment member 500 is composed of an upper X-ray alignment plate 500 ₁ and a lower X-ray alignment plate 500 ₂ . The positional relationship between the holes of the upper X-ray alignment plate 500 ₁ and the lower X-ray alignment plate 500 ₂ is determined by the X-ray 103 passing through the pinhole member 104 to the accumulation type image sensor 200. It is arranged to reach. Each hole can be machined separately for the upper X-ray alignment plate 500 ₁ , and for the lower X-ray alignment plate 500 ₂ , and the hole processing is performed because the X-ray alignment member is thin. Since the vertical is good with respect to, it is easy to process.

On the other hand, when the X-ray alignment member 500 is formed as a single plate as shown in FIG. 22, the hole needs to be obliquely processed with respect to the plate, and the inclination angle of the hole changes at a constant angle, making it difficult to manufacture. . In addition, although the shape of the hole is also illustrated as a circle in FIG. 23, it is advantageous that the X-ray alignment member is thin to have any shape such as square or hexagon.

25 is a schematic diagram showing the positional relationship between the holes of the X-ray alignment member and the pinhole member. The radiation radiated from a two-dimensional or three-dimensional radiation source (not _shown ) has the same pitch in the holes of the upper X-ray alignment plate 500 ₁ and the lower X-ray alignment plate 500 ₂ , respectively, and the center of each hole is the same. If the coordinates are in proportional relationship (i.e., proportional enlargement or reduction), the X-rays 103 passing through the two X-ray alignment plates 500 ₁ and 500 ₂ are focused on radiation at one point. Becomes The focusing of the above-mentioned X-ray speed group at one point is geometrically demonstrated with reference to FIGS. 26 and 27.

FIG. 26 is a partial schematic view of FIG. First, let C be the point where the extension of the radiation AB and DE intersects. In Figure 25, the extension of the EG proves to pass through C. ADF and BEG are parallel, AD = DF and BE = EG. For example, G 'and G' correspond to G at the point where the line connecting F and C intersects the lower X-ray alignment plate 500 ₂ . Triangular CDF is analogous to triangular CEG '. In addition, triangle CAD is similar to triangle CBE. Therefore, BE = EG 'because AD = DF. BE = EG for equi pitch family. Thus, EG = BE = EG ', that is, G and G' proved to match.

In addition, Fig. 25 is a plan view, but the above proof is equally true even in the three-dimensional case, so the upper X-ray alignment member is planar, and the lower X-ray alignment member is also planar, and X-converging at one point is focused. Line speed groups are also largely distributed on the plane.

28 is a partial enlarged view of FIGS. 2A-2C. In FIG. 28, the X-ray, X ₁ is transmitted through B ₁ , B ₂ , B ₃ ...., A, .... E ₄ , E ₃ , E ₂ , E ₁ while being absorbed in each part The accumulating image sensor is reached. In this process, when there is a very strong absorption portion (for example, B ₃ ), the tomographic image value near the B ₃ point of the specific tomographic surface SL ₁ of the subject 100 is affected.

In FIG. 28, the effect of B3 is schematically represented by taking the coordinates of the subject's direction on the horizontal axis and the image signal value (the absorption band is taken in the direction of the signal station) on the vertical axis. have. That is, even if all X-rays, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ ....... X _N (where N is a large number), the image signal value of the total A point remains, the effect of B ₃ remains. There is a case. B ₃ of influence affects every part of the vicinity of B _3. The reason is that the X-rays passing through B ₃ are present over at least 50 °. Therefore, the influence is a low frequency (that is, a low frequency because it is not sufficiently averaged) as a component of the electromagnetic waveform. When the electronic processing called a high-pass filter in an electronic circuit technology (i.e., does not pass a high-frequency component and passes a low frequency component) is a signal waveform such as that described as the image signal to remove 28 showing the low frequency component B ₃ The effect of the point is to be alleviated.

As an example, when the subject is a human body, when the tomographic image is observed to determine the lesion part and to determine the lesion symptom, it is preferable that the tomographic image is visually seen in three dimensions. There is. For example, in the diagnosis of an image of a particular organ, it is easy to judge the relation between a particular organ and its surroundings in which the film images before and after the inner and longitudinal directions of the organ are thinly overlapped and three-dimensionally visible. Will be good.

On the other hand, the CT method is, in principle, imaging of only one tomography, and there is no information in the depth direction. Therefore, in order to generate a three-dimensional image, it is necessary to generate from a plurality of tomographic images, which requires generation time. In addition, since there is a distance between tomography, the generation of complete stereoscopic image is disturbed. In the tomography imaging method, in the CT method, there is a possibility of generating a false image (arch fact) in principle. However, since the present invention is a direct tomographic method, no calculation for generating tomographic images is required and essentially no false image occurs.

EMBODIMENT OF THE INVENTION Below, the Example of this invention is described with reference to drawings. 29 is an embodiment of the present invention in medical use. As illustrated in FIG. 29, a bed 11 is installed on the floor 10. The living subject 12 is placed on the bed 11. In the bed 11, the X-ray sensor unit 14 installed in the frame device 13 is placed inside the bed 11, and the upper part of the bed 11 is supported by a support (not shown). The X-ray source 15 is arranged.

The frame device 13 includes an attachment member 17 and a frame 18 for attaching the frame drive device 16 installed on the bottom 10 and the X-ray sensor unit 14 connected to the frame drive device 16. And an X-ray shield body 19 having an X-ray alignment member 500 punched at the same pitch.

The frame drive device 16 repeatedly moves the attachment member 17, the frame 18, and the X-ray shield body 19 in the direction of the drawing 40 integrally. An X-ray generator 15 is connected to a high voltage supply device 20 and a cathode power supply 21 for radiating a predetermined X-ray 31 from the X-ray generator 15. Supply power for high voltage and negative electrode required in (15). Two-dimensional and three-dimensional radiation source 15 is an X-ray tube in this embodiment, and has a form in which a plurality of radiation sources 15 are attached side by side as shown in the drawing. The reason for taking the form of attaching a large number side by side in this way is to increase the forward angle.

The X-ray tube is supplied with high voltage power from the high voltage power supply 20, and the X-ray 31 generated from the negative power supply 21 is partially provided with the X-ray shield 19 and X-. It is blocked by the ray alignment member 500, and the other passes through the X-ray alignment member 500, and passes through the human body that is the subject 12 to enter the X-ray sensor unit 14. The X-ray sensor unit 14 is mainly composed of a CCD which is an X-ray semiconductor detector, and is driven by the CCD drive circuit 22. The output from the X-ray sensor unit 14 is introduced into the signal processing system 30. The signal processing system 30 includes an image memory 31, a tomographic image conversion circuit 32, a display 33, an image filter 34, a high pass filter 35, and the like. The high pass filter 35 is placed in parallel with the tomographic image conversion circuit 32 between the image memory 31 and the display 33 as necessary. In addition, the image memory 31 and the display 33 can be directly connected as necessary.

The details of the X-ray sensor unit 14 are shown in FIG. 30 and hold three X-ray sensor elements 14A, 14B, 14C. Each of these X-ray sensor elements 14A, 14B, 14C holds a pinhole member 40 and a detector 41 which are spatially coupled. Each detector 41 of the X-ray sensor elements 14A, 14B, 14C is composed of a scintillator 41A, an image intensitier (II) 41B, and an optical system. system) 41C and an area CCD photographing sensor 41D which is an accumulation type image sensor.

Here, the subject 12 is stationary, and the detector 41 including the shield, the X-ray alignment plate 500, the space combiner 40, and the accumulation type image sensor 41D is fixed by the frame 18. It is. The frame 18 is reciprocated at a high speed by the frame driving device 16 as shown in FIG. If three accumulated image sensors are shown in FIG. 30, and three rows of accumulated image sensors are juxtaposed at right angles to the direction of movement of the frame, a single image of 3x3x2 = 18 layers in one round trip of the frame. Is obtained. If the reciprocating motion of the frame 18 is reciprocated 10 times in one second, a tomographic image is obtained with 3x3x2x10 = 180 layers in one second.

The movement of the accumulated charge of the CCD in the area-type CCD photographing sensor 41D, which is an accumulation type image sensor, has been described, and the movement of the accumulated charge is equivalent to the movement speed of each tomogram of the subject. 22, a drive signal is supplied. The signal output from the area-type CCD photographing sensor 41D is sent to the tomographic image original memory 31 for storage. When the tomographic angle conversion is unnecessary, it is directly transmitted to the display 33 and the image file 34 shown through the high pass filter circuit 35 shown in the figure, and the display and recording retention of the tomographic image is performed. Is done. If a tomographic image of an angle that is not parallel to the equivalent moving direction of the subject is required, the tomographic image conversion generating circuit 32 of FIG. 29 is converted into a tomographic image of the required angle and transmitted to the display 33 and the image file 34. do. Here, the tomographic image conversion generation circuit 32 includes a high pass filter circuit 35 if necessary in this case.

Another embodiment of the present invention will be described with reference to FIGS. 31-35.

In FIG. 31, the object 100 is a steel slab produced by a continuous casting machine, has a high temperature heating state, and moves in a direction indicated by an arrow as a traveling direction. The typical appearance of the steel slab is the shape shown in FIG. 32, which is about 150 mm thick, about 1 m to about 3 m wide, and about 100 m in total length, and progresses in the direction indicated in the drawing at about 0.1 m per second.

The cross-sectional shape of the steel slab shown in FIG. 32 is spherical. The purpose of the tomographic imaging of the steel slab is mainly to determine the good quality, poor quality of the product. The defective items of the product include the mixing of foreign matter, the gap between the surface layer, the gap near the surface layer, and the spatial layer near the surface layer. Among the defects of these products, one should pay attention to defects near the surface layer. For example, gaps near the surface layer are harmful, and may remain or expand in the rolling process of the next step, but when present in the interior far from the surface layer, they are compressed and harmless in the pressing step of the next step. On the other hand, mixing of foreign matters is harmful without distinguishing between the surface layer and the deep layer.

As described above, in-line product inspection of steel slabs is insufficient for the entire batch inspection in the thickness direction, and inspection of each layer in the thickness direction is required, and a tomographic image is required.

In FIG. 31, the high voltage power supply 20 adds a high voltage to the X-ray tube 15 having a two-dimensional or three-dimensional source which is a radiation source. The cathode of the X-ray tube 15 is heated by the electric power supplied from the cathode power supply 21. The X-ray tube 15 is accommodated in the X-ray tube storage box 39A and protected from the surrounding high temperature atmosphere. Therefore, the water cooling pipe 39B is disposed and cooled by the cooling water. In addition, on the X-ray emission side, a heat radiation reflecting plate 15A reflecting the heat rays from the red iron plate slab is disposed on a thin iron plate with good reflecting nickel coating or the like.

X-rays radiated from the X-ray tube 15 pass through the steel slab that is the object 100 and enter the X-ray sensor unit 14 as shown in FIG. It passes through the pinhole 40 to the X-ray sensor unit 14 and enters into the area type CCD photographing sensor 41D which is an accumulation type image sensor. The area CCD photographing sensor 41D is disposed at least three in the moving direction of the subject 100 and in the width direction of the subject 100 in the range of several to several hundreds as shown in FIG. At least three accumulation type image sensors are disposed in the moving direction of the subject 100 so that at least three layers, for example, an upper surface layer, a center layer, and a lower surface layer, are imaged.

The signal of the imaged layer is processed as shown in FIG. In FIG. 34, the CCD output is taken on the vertical axis, and the width direction coordinate is taken on the horizontal axis. If there is a gap or the like, the signal increases because the X-ray transmittance is improved. This is compared with the inspection level to determine whether there is a defect. The output signal of the area CCD photographing sensor 41D is processed by the tomographic image memory 31, the high pass filter circuit 35, and the tomographic image abnormality inspection circuit 37, and the determination result is output to the alarm output device 38. do. On the other hand, the image of the upper part of the tooth is accumulated in the upper image memory 36 and output to the display 33 such as a CRT. Also, the area CCD photographing sensor 41D is housed in a water-cooled image sensor box in the same manner as the X-ray tube because of heat dissipation.

In addition, in FIG. 31, the three-layer tomographic inspection is shown, which is called the number of inspection floors. The number of image sensors is increased in the direction of travel of the subject, or a plurality of blocks in the direction of travel of the subject are shown in FIG. It is also possible to increase the number of inspection floors by installing.

Another embodiment of the present invention will be described with reference to FIG. In FIG. 35, the object 100 is a die cast product 62 which is an industrial product. The die cast products are made from the same mold, so their dimensions and shapes are the same. However, quality problems such as defects, defects, etc. occur in the die cast castings and require inspection in quality control. On the other hand, even if there is a defect, there is a case where it does not become a problem in terms of quality and function depending on the existing part. Therefore, it is desirable to perform the inspection for each specific fault. As shown in FIG. 35, the subject 100 is placed on the belt 61 of the belt conveyor and is transferred discretely or continuously. The belt 61 is transferred to the roller 60. The roller 60 is driven by the motor 63 driven by the motor drive circuit 64.

In FIG. 35, two area CCD photographing sensors 41D are disposed, and a case of performing a two-layer tomographic inspection is shown. The output signal of the area CCD photographing sensor 41D is an image memory 51A, ( It is stored in 51B, and is compared with a signal from the reference image file 53 of a subject of good quality through the reference image memories 52A and 52B to the image comparison circuits 54A and 54B. If it is determined that the result of the comparison is abnormal, the image is displayed on the display 33, and the alarm processing circuit 55 transmits the abnormality determination result to the gate driving circuit 56. The gate driving circuit 56 receives the abnormal determination signal, opens the gate 57, and classifies the product.

The object of the present invention is to obtain a clear X-ray image, tomographic images in a short time, and to obtain a three-dimensional tomographic image, as mentioned in the technical problem to be achieved by the present invention to be described below, a small amount of coating The present invention provides a radiographic imaging method and system for acquiring a transmission X-ray image of a living subject or a non-living subject and a tomography image thereof.

Claims (12)

A convergence type X-ray generating unit for generating an X-ray including an X-ray bundle that converges at a predetermined position, and the convergence type X-ray generating unit to face the subject; And a pinhole member disposed between the object and the X-ray detector, and a signal processor for signal-processing an output signal from the X-ray detector. Radiographic imaging system. The radiographic image according to claim 1, further comprising: a pair of the converging X-ray generating unit, the pinhole member, the X-ray detecting unit, and moving means for relatively moving the subject. Imaging system. The X-ray detector of claim 1, wherein the X-ray detector includes an accumulation type two-dimensional X-ray detector, and the accumulation type two-dimensional X-ray detector is configured to store accumulated charges with the subject and the X-ray detection unit. And means for moving at a movement speed corresponding to the relative movement speed of the apparatus. The radiographic imaging system according to claim 1, wherein the converging X-ray generator includes a plurality of converging X-ray generators arranged in parallel. The X-ray detector according to claim 1, wherein the X-ray detector moves accumulated charges, and the moving charge CCD that adds and accumulates charges of the mobile add CCD are moved relative to a specific tomographic plane in the subject and the X-ray detector. And moving means for moving at a movement speed corresponding to the radiation image pickup system. The radiographic imaging system according to claim 1, wherein said signal processing system includes a high pass filter. The radiographic image capturing system according to claim 1, wherein the pinhole member has a function that the convergence and divergence angle of the X-ray is 50 ° C or more. The radiographic image capturing system according to claim 1, wherein the pinhole member and the X-ray detector are disposed in close proximity to each other. The radiographic imaging system according to claim 1, wherein the pinhole member includes a pinhole plate and a slit plate. The apparatus of claim 1, further comprising an alignment member for suppressing the amount of X-rays not incident on the X-ray detector between the converging type X-ray generator and the subject to irradiate the subject. A radiographic imaging system. According to claim 1, wherein the alignment member has a first alignment plate and a second alignment plate arranged in parallel, these plates are formed with a plurality of holes, proportional reduction or proportional enlargement of the center coordinates of the holes of the second alignment plate It is set to one thing, The radiographic image imaging system characterized by the above-mentioned. A step of generating X-rays to converge at a predetermined position, irradiating the generated X-rays to the subject, detecting the transmitted X-rays passing through the subject through the pinhole member, and signal processing the detected signals A method for imaging an X-ray image of a subject having a step.