JPS58159730A - Radioactive ray fluoroscopic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radiographic apparatus capable of correcting distortion of a radioscopic image of an object obtained by radiation.

[Technical background of the invention]

Radiation, especially XII, is used as a fluoroscopic means in various fields by utilizing its material permeability, and in particular, in the field of non-destructive testing, the role of X@fluoroscopy equipment is to obtain a fluoroscopic image g11' of a subject. Large O By the way, this type of equipment can be roughly divided into an X-ray source that irradiates the Xll object, an X# sensor that receives the radiation mf and outputs a signal according to the ray intensity, and a signal from the X-ray sensor. Displays image plate rims and TV image tucks according to line strength! It is composed of the 1j Health Creation Department. Among these, the X-ray sensor includes an area sensor and a line sensor. This is to detect a fan beam of radiation that is irradiated in a fan shape.

Here, the fluoroscopic images of the subject due to the radiation detected by both of the X-ray sensors are somewhat different even for the same subject due to the difference in shape of the radiation beams. For example, if a cylindrical object as shown in Fig. 1(a) is irradiated with the above-mentioned radiation beam in the direction of the arrow while moving the object, the fluoroscopic images will be shown in Fig. 1(b) and (), respectively. e
) The image will be as shown in K. Note that (b) is a diagram showing a fluoroscopic image of a broad radiation beam; the shaded area in each diagram indicates the size of the actual subject, and the arrow indicates the direction of movement of the subject. be. As is clear from the figure, Broad Sugibayashi's radiation beam, that is, the fluoroscopic image using the X-ray area sensor, is larger overall than the actual shape. In addition, a fluoroscopic image obtained using a fan-shaped radiation beam and a toothed X-ray line sensor shows a circular cedar forest that is larger in the direction perpendicular to the moving direction of the subject compared to an actual cedar forest.

With the conventional XM transparent device, XII! Area sensors are mostly used as sensors.

[Problems with background technology]

By the way, as described above, a fluoroscopic image of a subject obtained by X-rays has a difference in shape from the actual image.

In particular, this shape difference is not uniform at each point of the object, and is smaller at the center of the object and becomes larger as it approaches the periphery. This is due to the thickness of the object and the fact that the X-ray source is a point source. As shown in FIG. 2, when an object 1 with a thickness H is irradiated with radiation St from a point-shaped X-ray source 2, each point U, V, W, and X of the object 1 is projected onto the projection plane 3. Each point U',
V'IW' l X' are respectively projected.

Therefore, although U, ■ and W,
'~v' and W'~X' have a deviation t, and U-X
(or ■~W) <U'-X' (or V
-W). This U-X (or v-W)
The difference between U' and U'~X' (or v-w) and the deviation of U' and V/ (or W' and This is a big obstacle to doing so.

[Purpose of the invention]

An overall object of the present invention is to provide a radiographic apparatus that uses an X-ray line sensor to correct distortion of the radiographic apparatus due to the thickness of a subject and the radiation irradiation angle.

[Summary of the invention]

In order to achieve the above object, the present invention provides a first radiation detector for detecting radiation irradiated perpendicularly to the subject by directing a radiation irradiation beam from a radiation source to the subject; A second radiation detector is installed to obliquely irradiate the object, and the radiation source is projected based on the geometrical arrangement of both detectors and the radiation source and the projection data according to the thickness of the object due to the radiation from the dotted radiation source. In this way, the present invention provides a radiographic fluoroscopy apparatus capable of correcting the distortion of the fluoroscopic image of the subject obtained from both of the detectors.

[Embodiments of the invention]

An example of an XM fluoroscope using the t-X-ray line sensor of the present invention will be described.

First, the outline of the X# line sensor will be explained with reference to the road outline diagram in FIG. Reference numeral 3 denotes an ionization chamber filled with gas, and signal electrodes 5 and high voltage electrodes 6 are arranged alternately in the opening 4 of this ionization chamber 3, and the schematic connection diagram of both electrodes 5 and 6 is shown in FIG. As shown in the figure, the high voltage electrode 6 is connected to the high voltage line 7, and the signal electrode 6
are connected to each signal line 81-S. However, the gas is ionized by the 2X rays that enter the vicinity of each signal electrode, and subsequent charges are collected on the nearby signal electrodes in accordance with the dose.

Therefore, electricity can be extracted from the signal line according to the radiation dose.

Next, the 4th g! ! ! + shows a configuration diagram of an embodiment of the radiographic apparatus of the present invention. That is, 10 is a XiI tube that emits X5t-, and a fan beam collimator 1 is arranged at the radiation output port of this X-ray tube 10 to output the irradiation beam in a fan shape in two directions at an angle α. In front of the output of the fan beam collimator 11, a conveyor 13 driven by the conveyor drive unit 12 carries the subject 141'' and moves in the direction of the arrow. The intersecting X-ray tubes 10
A first X-ray line sensor 5 is arranged in the direction of radiation irradiation, and this X-ray line sensor 15 and the X-ray tube 1-
An X-ray line sensor 15 that has an angle α with respect to the connecting line and is parallel to the moving direction line of the conveyor 13 within the same plane.
A second X-ray line sensor 16 is placed on the line. These X and I line sensors 15 and 16 are those described above.

And Xll1! In order to convert all the signals output from the line sensors 5 and 16 into total signals, integrators 15-1 and 16-1 are installed after these X-ray line sensors 1B and 16, respectively. This integral 615-1,
Each multiplexer 1 converts the output of 16-1 into a time division signal.
5-2, 16-1 and each A-D converter 15-3, 16-3f that converts the time division signal into a storage digital signal:
establish. Furthermore, each storage digital signal is converted into a perspective image,
Pre-memories 15-4 and 16-4 are provided for storing signals.

Then, commands for writing and reading to and from these prefix memos IJ 15-4 and 16-4 are issued by the prefix memory controllers 15-5 and 16-5, respectively. Also, the command timing of the pre-memory control units 15-6 and 16-5, the resetting of the integrators 15-1 and 16-1, the input timing, and the multiplexer 154.

The timing controller 17 controls the data selection timing 16-2.

15-6 and 16-6 are the respective pre-memories 15-4;
, 16-4, respectively, to extract partial images having the same specific part of the subject 14 (such as a characteristic bright part, appetizer part, or shape part of the subject 14) from both fluoroscopic images stored in 16-4. This is a partial image extraction circuit. The partial images extracted by these specific partial image extraction circuits 15-6 and 16-6 are of the subject 14, which has a deviation due to the difference in the detection positions of the X-ray light/sensors 15 and 16. This is a partial image of the same point in . Further, a distance calculator 18 calculates a straight line deviation distance in the moving direction of the subject 14 from this deviation.
and a thickness determiner 19 for determining the height and thickness of the specific portion from the conveyor level based on the amount of distance between the partial images calculated by the distance calculator 18. In this thickness determiner 19Vc, a relationship between the deviation distance between the partial images and the thickness of the subject 14, which will be described later, is set.

Reference numeral 20 denotes a figure correction circuit, based on the thickness information from the thickness determiner 19, corrects the reported area size from the specific partial area total oil circulation wIzs-e in accordance with the respective thickness information. .

This correction ■ is carried out by the correction amount memory 21 in which the correction amount (enlargement amount) corresponding to the thickness is stocked, and the sys-type correction circuit 2o.
is called. Then, each partial image corrected by the graphic correction circuit 20 is stored as a whole perspective image in a final one-way memory 22, and this is converted into an analog signal by a display unit 23 and displayed on a cathode ray tube or the like. Alternatively, it is outputted to the outside through the output terminal 24 as a digital image signal. Note that each timing of writing and reading to and from the final ms memory 22 is determined by the timing signal of the timing controller 17.
Memory 25 performs this.

Next, the operation of the apparatus configured as described above will be explained. First, by using the contents set in the distance calculator 18, thickness determiner 19, and correction amount memory 21, and the geometric relationship diagram between the thickness of the object 14 and the X-ray detection position shown in FIG. explain. In the same figure, the X-ray irradiation direction is perpendicular to the conveyor 13 from the XIII source F, and the next
#X-ray line sensors 15 and 16 are arranged in the irradiation direction, respectively. In this forest condition, when the subject 14 comes to the position indicated by the solid line by the conveyor 13, the next example is to set points A, B, C, and D on the rear vertical plane of the subject 14 and move the conveyor 13 at these points. Each point A, B, C of the subject 14
, D) are respectively Hs r H (+ HD
Then, the X-rays entering the X-ray line sensor 16 are at points A and B at the same height as the points A, B, C, and D.
', C', and D'. Next, subject 1
4 comes to the dotted line position, the X-ray line sensor 16
XIa entering the line passes through B' I C' I D' and is the next one. Similarly, as the subject 14 moves, the X-rays that have passed through C' and D' and the X-rays that have passed through D'
Lines are entered sequentially. In other words, the X-ray signal for the vertical plane of the extraction part of object 4 should originally be an incident X-ray with no time width, but because the X-rays are irradiated obliquely, it is expanded by the X-ray signal that enters with a time width. (stretched ft,
)ijilI. On the other hand, X-ray line sensor 1
During the fluoroscopy step 5, since the X-rays are irradiated perpendicularly to the subject 14, the image cannot be enlarged as described above. Next, if the relationship between the deviation distances of both fluoroscopy 1iii* by both sensors ys and 16 is known from the difference in the detection positions of both sensors 15 and 16, based on this relationship, both sensors 15 and 16 can be determined.
Based on the image shift distance, the points B', C', and D' in the same figure are determined based on the X-ray incoming line R of the X-ray line sensor 16.
The distance LH+L2, L wealth is found.

(1) The relationship between the image shift due to the difference in the detection devices is based on the X-ray input lines of both sensors 15 and 1g and the conveyor 13.
The distance Li between the intersection points is measured, and the relationship between this distance and the deviation on the image plane between the two intersection points is used. Above, the distance LI
By ILI ILI, as is clear from the figure, the formula (
L Ii1~. )/lanα−(1) to each point B, C
, D height and thickness) Har HctHa can be found.

Therefore, based on the above concept, the thickness of the subject 14 can be determined from the image shift between the two sensors 15 and 16 of the subject 14. Furthermore, since the relationship between the thickness of the subject 14 and the degree of enlargement of the projected image is as shown in FIG. Used when making corrections.

That is, the distance calculator 18 having the configuration shown in FIG. −
Based on the basic deviation distance on the fluoroscopic image and the deviation distance of the fluoroscopic image of a specific part of the subject 14 based on this basic deviation distance, calculate the distance corresponding to Ll (t Lt , Ls)K in Fig. 111.5 above. The calculation function to be calculated is set.

Further, the thickness discriminator 19 is set to abrasion (1), and outputs a signal indicating the thickness of the subject 14. Furthermore, the relationship between the thickness and the enlargement degree of the projected image shown in FIG. 2 is set in the correction amount memory 2.

Therefore, the signal corresponding to the amount of X-ray fluoroscopy of the subject 14 detected by the X-ray line sensor 15. It is integrated every time. This integrated signal is time-divided by each multiplexer IB-2 and J6-2, and A-D
The signals are converted into digital signals for storage by converters 15-3 and 16-3, respectively. Furthermore, these digital signals are transmitted to each prefix IJ 15-4, 1g-4 of the subject 1.
The images are stored as four perspective images, respectively. From these fluoroscopic images, partial images of the subject 14 that include the same specific shape GATA t-Specific portion iiiigI! Extraction circuit zs-6,1
Extract according to step 6-6. Based on the difference between the two partial image data, the distance calculation unit 18 calculates the deviation distance between the two specific parts, and the above-mentioned conveyor 14
C) The distance between the X-ray irradiation points of the subject 14 at a certain thickness from the level (#L, described above) is calculated. This distance signal is input to the thickness determiner 19vC, the thickness of the specific portion from the conveyor level is determined, and the signal is input to the graphic corrector 20. The figure corrector 20 receives the specific partial image a'r-y from the Takeda partial image extracting circuit 15-6, and stores this image data in the correction memory 2 and stores it in the next image. Correct the deviation distance corresponding to the distance.

This corrected image data is stored in the final memory 22. In this way, the corrections for each portion are stored in the final memory 22. Then, the final memory 22 stores a fluoroscopic image that has been corrected and corrected (contracted) for expansion in the direction perpendicular to the moving direction of the subject 14, and is output to the display unit 23 or output terminal 24. .

By the way, in the above embodiment, the value of L for ablation (1) was set above the level of the t conveyor 13, but this L value was corrected by using the X-ray inspection of 1 MX-ray light/sensor 15.16 as described above. can. That is, the deviation due to the thickness (U
In addition to the difference between .about.V and U'-v', it is also possible to correct deviations due to oblique incidence of radiation (difference between .about.W and v'-, -w'). A fluoroscopic image that is faithful to the subject 14 obtained when the desired X1IiI is irradiated can be obtained.

In addition, although shrinkage correction was used in the above embodiment, the subject 14
It is also possible to correct the perspective image by enlarging it in the direction of movement. Also, Xll1! Although this was done with two line sensors, it is also possible to use two or more, and it is also possible to scan a single channel sensor to the left and right without using the XIs line sensor, and then use a part of the area sensor for fc, etc. However, various modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, it is possible to correct distortion of a fluoroscopic image of a next subject that is fluoroscopically viewed using radiation.

Therefore, it is possible to produce an image of the subject that is easy to visually inspect, and it is possible to improve the precision of detailed inspection. In other words, it is possible to provide a radiographic apparatus that can produce images comparable to those of an Xls area sensor.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a perspective image of a subject using the fan beam and cone beam of the irradiation beam of Hiroshi radiation; Figure 2 is a diagram showing the projected position of the subject on the projection plane by a point forest X-ray source;
Fig. 3 is a diagram of the outline of the X-ray line sensor, Fig. 4 is a configuration diagram of an embodiment of the radiographic apparatus according to the present invention, and Fig. 5 is a geometric diagram of the thickness of the subject and the X-ray detection position. It is a relationship diagram. 10... X-ray tube, I4... Subject, 15.16...
・X-ray line sensor, 15-1, 16-1... Integrator, 15-2, 16-2... Multi-breather, 15
-3゜16-3...A-D converter, I5-4, 16
-4... Preliminary memo IJ, 15-6, 16-6...
・Specific partial image extraction circuit, 18...Distance calculator, 19
...Thickness determiner, 20...Graphic corrector, 21...
Correction amount memory, 22...Final memory. Figure 1 (a) (b) (c) Figure 2

Claims (1)

[Claims] A subject moving within a radiation irradiation area, a radiation source that irradiates W4 radiation perpendicular to the direction of movement of the subject, and a subject placed directly opposite the radiation source. a first radiation detector that outputs a signal tube according to the amount of radiation transmitted through the specimen; A second lens which is geometrically located at the other vertex of the triangle with the t2 vertex and which outputs a signal corresponding to the amount of radiation transmitted through the subject.
a radiation detector; a storage means for converting the signals of the first and second radiation detectors into fluoroscopic image digital signals and storing the converted signals; The same image of the subject from both perspective paintings by
A specific partial image extraction circuit that extracts a partial image including the specific part 1; A distance calculator for calculating a radiation irradiation interval between partial images, and a correction means for outputting an amount based on a distance signal of the distance calculator, and the distortion t-correction of a fluoroscopic image of a subject is performed by the correction means. A radiofluoroscopy device characterized by: