JPS6266776A - X-ray image pickup device - Google Patents

Abstract

PURPOSE:To eliminate influences of diffused X-ray and veiling glare and improve resolution by making the difference signal between the largest signal and the smallest signal of each picture element during whole period of scanning of X-ray flux picture image signals. CONSTITUTION:Pulselike X-ray 13 from an X-ray generator 1 becomes X-ray flux 14 through an X-ray slit 2 and irradiated on an object 3. Transmitted X-ray is made incident on an X-ray image tube 5 and becomes a light image and is picked up by a TV camera 7. Signals of the camera 7 are compared with signals of frame memories 8b, 9b for each picture element by signal comparators 8a, 9a and larger signal is stored in the memory 8b, and smaller signal is stored again in the memory 9b. Same operation is repeated shifting the slit 2. The signal of the memory 9b is subtracted from the signal of the memory 8b by a signal computing element 10b and recorded in a memory 11 and made to picture signals. By this way, resolution is improved.

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an X-ray grating consisting of a two-dimensional grating having a number of X-ray transparent slits or a plurality of apertures. The body is scanned and the ray flux produces striped X-ray images or island-like X-ray images.
The present invention relates to an X-ray imaging device that integrates ray images and reproduces them as an X-ray image of the object, thereby obtaining a clear X-ray image from which X-rays scattered by the object and verifying glare from an X-ray image tube are removed. [Technical Background of the Invention] Conventional X-ray imaging devices use lead foil and X-ray foil to remove X-rays. An X-ray grid in the form of a lattice is placed between the subject and the X-ray image tube to allow as much of the primary X-rays as possible to pass therethrough and to remove as much of the scattered X-rays generated from the subject as possible. However, in order to prevent the resolution of the X-ray image from deteriorating, this lead foil cannot be made too thick. Also, since the transmittance of -order X-rays is not lowered too much, the lead foil cannot be made too thick or long. Therefore, the effect of removing scattered X-rays is not necessarily sufficient. Furthermore, X-ray image tubes have scattering of X-rays, light, and light inside the tube, resulting in significant image blurring called Bering glare. In order to prevent these, we use an input window material with low X-ray scattering, use a columnar crystal structure fluorescing surface that has a large light guiding effect on the input phosphor surface, and transfer unnecessary fx and ' to the output fluorescing surface. Efforts have been made to improve the electrode structure and reduce the transmittance of the glass substrate on the output fluorescent surface, but this is not always sufficient. Therefore, multiple X-ray slits are placed between the X-ray source and the subject so as to cover the entire X-ray image receiving surface.
This slit is scanned between the slits,
Attempts have been made to remove the effects of X-ray scattered radiation and Bering glare by extracting only signals corresponding to the scanning of the slit and combining them into one X-ray image. [Problems in the Background Art] In order to scan an object with a plurality of X-ray slits and image the portion corresponding to the transmitted X-ray image of the object corresponding to the X-ray flux with a television camera (hereinafter referred to as TV camera). It is necessary to accurately control the imaging position in synchronization with the scanning of the X-ray flux. The accuracy of the control corresponds to the resolution required for the screen, so it must be extremely precise, making it a very expensive device. Furthermore, since the X-ray image tube has a characteristic of image distortion in the form of a Kevin cushion, a straight line in an X-ray image is not necessarily a straight line, and alignment thereof is extremely difficult. Furthermore, if there are too many X-ray pulses making up one screen, it will take too much time to capture the image, and the problem of motion blur of the subject will occur.
It is preferable to increase the number of slits to reduce the number of X-ray pulses below a certain limit. In this case, there are drawbacks such as scattered X-rays due to a large number of slits, and the effects of overlapping beams and glare. [Object of the Invention] The present invention scans an object with an X-ray flux using an X-ray transmission slit scanning means having a plurality of X-ray slits or a plurality of X-ray apertures, and generates an X-ray image transmitted through the object by the X-ray flux.

The output image of the X-ray image tube is captured by a TV camera to compose the image (in this case, it is difficult to capture the image without synchronizing the image capture of the TV camera with the scanning position of the X-ray beam).
We provide a device that does not require a complicated and expensive synchronization mechanism, and also
The maximum signal and minimum signal of each pixel during the entire scanning period of the bundle
It is an object of the present invention to provide an apparatus which can reduce the influence of scattered X-rays due to a large number of X-ray fluxes and Bering glare by using a total subtraction signal. [Summary of the Invention] The present invention includes an X-ray source, an X-ray image tube that receives an X-ray image transmitted through an object and converts it into a light image, a television camera that captures this light image, and an imaging signal that receives this image signal. In an X-ray image pickup device including a receiver that displays an image, a KX
An X-ray grating that covers the entire surface of the X-ray image receiving surface of a ray image tube, has a plurality of two-dimensional X-ray transmitting slits, and has an X-ray shielding section larger than a pixel between each adjacent X-ray transmitting slit. Then, the object is irradiated with the X-ray flux formed by the X-ray transmission slit in a pulsed manner, and the X-ray grating is irradiated with the two-dimensional surface of the X-ray transmission slit at a distance greater than the maximum value of the gap between each adjacent X-ray slit. an X-ray transmissive slit scanning means which scans in a direction perpendicular to the slit, and scans with the X-ray flux little by little overlapping each pulse; a means for taking an image; a means for erasing all remaining signals in one memory before the X-ray grating captures the subject; and a means for erasing all remaining signals in one frame memory; means for comparing the signal of the camera with the signal of the former frame memory for each pulse of X-rays; means for recording the larger signal in the former frame memory again; means for comparing the signal with the signal of the other frame memory, and comparing the smaller signal with the signal of the other frame memory...D7
a means for recording in a frame memory, a means for recording the image in a frame memory, a means for performing this imaging Ct t until the X-ray transmission slit finishes scanning the subject, and then subtracting the signal of the other frame memory No. 11 from No. 48 of the former frame memory, and this subtraction. An X-ray imaging device characterized by projecting a signal onto a receiver. In addition, in contrast to the first invention, there are two inventions of an X-ray imaging apparatus characterized in that an X-ray grating is fixed and an X-ray source is scanned. [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG. Figure 1 shows the X-ray source, that is, the X-ray generator (1), the X-ray transmission slit (2), the X-ray grid (4), and the X-ray image tube (
5), optical system (6), TV camera (power, signal comparator A
(8a), signal comparator B (9a), frame memory A (8b), frame memory B (9b), frame memory C (10a), signal calculator (10b), receiver αD, synchronization signal; generator ( 1'IJ, consists of an X-ray dose measuring element (1e, X-ray transmission slit scanning mechanism (17). 131. This X-ray αJ generates a plurality of fan-shaped X-ray X-ray fluxes I by the X-ray slit (2), and this X-ray flux Oa passes through the object (3) and is transmitted by the X-ray grid (4). , a considerable part of the scattered X-rays generated by the object (, 3) is removed and the X-ray image tube (5)
incident on . Since this system has a function to remove scattered X-rays, the X-ray grid (4) is not necessarily required, but it is preferable to use it together. The X-ray image tube (5) converts the X-ray image into a light image. However, the X-ray image tube (5) generates a fairly large Bering glare due to X-ray scattering, light scattering, and generation of unnecessary electrons within the tube, and in addition to this, the scattered X-ray components of the incident X-ray image are also added. The output optical image of the X-ray image tube (5) becomes largely blurred. The brightness distribution of this output light image in the cross section of the X-ray slit (2) in the scanning direction is as shown in the 17th frame in FIG. Here, the scanning direction of the X-ray slit (2) is a direction perpendicular to the slit. In FIG. 2, the brightness i in the region b is the sum of the X-ray flux α corresponding to the transmitted X-rays, the scattered X-rays, and the Bering glare. The brightness in areas a and C is due to scattered X-rays from the X-ray flux I, light scattering, light emission by unnecessary electrons, scattered X-rays from the subject (3), and Bering glare from the X-ray image tube (5). Yes, it blurs the image and is unnecessary. A TV camera (
Capture frames using force. By using a type of image pickup tube for the TV camera (7) that accumulates a charge image on its input surface, such as a vidicon, the image produced by the pulsed X-ray can be changed from one pulse to the next pulse by a signal from the synchronization signal generation α. TV camera (7) by the signal of the synchronous signal generator α power in the time between
The image is captured by one-frame beam scanning. The signals of these frames are obtained as the signals of the first frame in FIG. Here, the gap between the slits is
No matter where the slit is positioned, the signal in the area 1, ] or C will be in the b area, as long as it is sufficiently dimensioned to prevent components with fairly low spatial frequencies such as light scattering and light emission by unnecessary electrons. The values are exactly the same except for the part where the signal is collected across both sides. 7L/-Mme-r:+)-A(8b)H Prior to imaging this first frame, all U numbers are erased by a signal from the synchronization signal generator (121).This frame memory A
The signal from (8b) and the signal from the TV camera (7) are also used as the signal from the synchronization signal generator u3, and the signal comparator (8a) compares each pixel with 1σ, and the larger signal is taken from the frame memory λ(
Record again in 8b). In parallel with this, all pixels are recorded in the frame memory I3 (9b) to the maximum recordable value of the signal using the signal from the synchronizing signal generator α2 prior to the imaging of the frame memory I3 (9b). This frame memory B
(9b) and the signal from the TV camera (7) based on the signal from the synchronization signal generator 02, the signal comparator (9a) compares the signal from the pixel area with the signal from the TV camera (7), and the smaller signal is selected from the frame memory B (
Record again in 9b). Next, the X-ray slit scanner (lη) and the X-ray slit are moved within a partial range using the signal from the synchronizing signal generator α2, and a second X-ray pulse is generated again using the signal from the synchronizing signal generator α2. The second frame is recorded in the same way.The signal from the TV camera is obtained by standardizing the X-ray dose of the X-ray pulse using the signal from the X-ray dose measuring element σG to eliminate the influence of fluctuations in the X-ray pulse. Repeat until the widest part of the gap between the Xi mislit slits is completely scanned by the slit.Then, the frame memory person (8b)
For K, in FIG. 2, an image is obtained in which the image of transmitted X-rays and the images of weakly scattered X-rays and Bering glare are superimposed on each region b. Also, in the frame memo IJ-B (9b), this weak scattering
Only those caused by lines and Bering glare are recorded. Therefore, a signal calculator (Job) converts the signal of frame memory A (8b) to 7 frame memory B (9
Frame memory C (10a) by subtracting the signal of b)
to be recorded. This signal is projected onto the receiver U. Since scanning is performed with the X-ray beams (14) partially overlapping, there is no restriction on the slit gap due to variations in the manufacturing of the X-ray slits.
or without image loss due to non-uniform scanning.
A high-quality image can be obtained that has very little influence from X-ray scattering of the object and very little influence from Bering glare from the X-ray image tube (5). Here, if the slit width of the X-ray transparent slit (2) and the gap between the slits are increased, Fig. 2 shows b.
The width of ``l ``an + CI ``''n becomes gradual, and the signal in the area b increases more than the sum of the signal from the transmitted X-ray and the signal at a sufficiently low point in a or C, This will result in an error. Further, if the size is too small, errors may occur in the manufacturing accuracy of the X-ray slit (2) and the slit scanning accuracy, which is undesirable. Furthermore, if the slit gap becomes smaller than one pixel, it will not be possible to obtain an area where no transmitted X-rays will be transmitted and the device will not function. Therefore, it is necessary to appropriately set the width of the slit and the gap as required. An X-ray shielding plate 03 having holes formed in a two-dimensional grid shape may also be used. In this case, the X-ray transmission window l31) is
→ b → C → d → e → f → g → h → i may be scanned while slightly overlapping. Such an X-ray g-shaped plate (33 is different from the X-ray slit (2)). Next, an embodiment of the second invention will be described. The aim is to obtain the same effect by scanning the X-ray source (1) instead of scanning the transmission slit (2).In other words, the X-ray source (1) is formed by the X-ray transmission slit in a pulsed manner. 121
), this X-ray transmission slit (slit on a two-dimensional plane of 2υ) is scanned perpendicularly to e211 at a distance greater than the maximum gap between adjacent X-ray slits (t211) The upper AC X-ray flux moves so that it overlaps little by little with each pulse. In this way, the same effect as the first invention can be obtained by relatively moving the X-ray source (1) and the X-ray transmission slit 12υ under certain conditions. [Effects of the Invention] The present invention provides an apparatus for obtaining a one-plane X-ray image with less influence of scattered X-rays and less Bering glare of the X-ray image tube by scanning the object with a plurality of X-ray fluxes using the above-described configuration. This has the advantage of providing a device that does not require an expensive synchronization mechanism associated with X-ray flux scanning.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a preliminary image configuration for explaining an embodiment of the present invention, and FIG. 3 is a diagram showing another embodiment of the present invention. Generates an X-ray flux of x1! A conceptual diagram showing an example of an iI shielding plate, and Fig. 4 is an explanatory diagram showing the scanning row of the X-ray flux in Fig. 3. ・Subject
4 X-ray grid 5 ・X-ray image tube 7 ・T
V camera 8a, 9a...signal comparator

Claims (5)

[Claims] (1) An X-ray source, an X-ray image tube that receives the X-ray image transmitted through the object and converts it into a light image, a television camera that captures this light image, and a receiver that displays this image signal. An X-ray image pickup device comprising: a plurality of two-dimensional X-ray transmitting slits covering the entire surface of the X-ray image receiving surface of the X-ray image tube between the X-ray source and the subject; An X-ray grating having an X-ray shielding part of one or more pixels is provided between the X-ray transmitting slits, and the subject is irradiated with the X-ray flux formed by the X-ray transmitting slits in a pulsed manner, and the X-ray grating is connected to each phase adjacent to each other. The two-dimensional surface of the X-ray transmitting slit is scanned in a direction perpendicular to the slit at a distance greater than the maximum value of the X-ray transmitting slit gap, and the X-ray beam is scanned while slightly overlapping each pulse. means for capturing an image of one frame with a television camera for each pulse of X-ray; and means for capturing a signal remaining in one frame memory before the X-ray grating starts scanning the subject; means for erasing all signals; means for setting the signal value to the maximum possible value on the entire surface of the other frame memory; and comparing the signal of the camera with the signal of the former frame memory for each X-ray pulse. means for recording the larger signal in the former frame memory again; means for comparing the signal of the camera with the signal in the other frame memory; and means for recording the smaller signal again in the former frame memory. means for recording in one frame memory of the former; means for performing this imaging until the X-ray transparent slit finishes scanning the subject; and then subtracting the signal of the other frame memory from the signal of the former frame memory; An X-ray imaging device characterized by projecting a signal on a receiver. (2) The X-ray grating has a plurality of apertures in the form of a two-dimensional grid, and by moving the X-ray grating multiple times by the X-ray transmissive slit scanning means, the subject is completely covered by the apertures. 2. The X-ray imaging device according to claim 1, wherein the X-ray imaging device emits an X-ray pulse each time it moves. (3) The X-ray imaging device according to claim 1 or 2, characterized in that an X-ray grid is disposed between the subject and the X-ray image tube. (4) A signal and frame in which the signal from the television is modified according to the X-ray dose of the X-ray pulse by arranging an element that measures the X-ray dose between the X-ray source and the X-ray transmission slit or the X-ray transmission control device. 4. The X-ray imaging apparatus according to claim 1, wherein the X-ray imaging apparatus compares the signal from the memory. (5) An X-ray source, an X-ray image tube that receives the X-ray image transmitted through the object and converts it into a light image, a television camera that captures this light image, and a receiver that displays this image signal. In an X-ray image pickup device comprising: a plurality of two-dimensional X-ray transmitting slits covering the entire X-ray image receiving surface of the X-ray image tube between the X-ray source and the subject; An X-ray grating having an X-ray shielding part of one or more pixels is provided between the X-ray transmitting slits, and the object is irradiated with the X-ray flux formed by the X-ray transmitting slits in a pulsed manner, and the X-ray source is Each phase of the transmission slit is moved so that the X-ray flux scans in a direction perpendicular to the slit on the two-dimensional plane of the X-ray transmission slit at a distance greater than the maximum value of the gap between adjacent X-ray slits, and the X-ray flux is an X-ray source including a means for moving the X-ray source so as to scan the X-ray source while slightly overlapping the X-ray beam; a means for capturing one frame of image with a television camera for each pulse of X-rays; means for erasing all remaining signals in one frame memory before starting scanning;
The two frame memories include means for setting the signal value to the maximum possible value on the front side, and means for comparing the signal of the camera with the signal of the former frame memory for each X-ray pulse.
means for recording the larger signal again into the former frame memory; means for comparing the signal of the camera with the signal of the other one frame memory; and means for recording the smaller signal again into the other one frame memory. means for recording in a frame memory; means for performing this imaging until the X-ray beam finishes scanning the subject; and then subtracting the signal from the other frame memory from the signal from the former frame memory; and transmitting the subtracted signal to a receiver. An X-ray imaging device characterized by being able to image.