JPH1147121A - X-ray television device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent re-photographing due to photographing errors with an X-ray television device by reducing blurring of a photographed image due to the movement of the subject of examination, even if photographing time is long. SOLUTION: A photographing device 5 photographing an optical image from an X-ray detector 4 and converting the same into an electric signal outputs a plurality of images in times series during one photographic process, under control of a control circuit 6 controlling the operation of the photographing device 5, and a movement-induced blur correction means 11 reducing the blur of the image due to the movements of the plurality of images is provided on the output side of the photographing device 5. Thus, even if the subject of examination moves during photography, the moving part in the image is not detected and added to the image as in conventional cases, so that the blur of the image due to the movement can be reduced. Therefore, the blur of the photographed image due to the movement of the subject of examination is reduced even if photographing time is long, and re-photographing due to photographing errors can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray television apparatus for irradiating a subject with X-rays to see through and photograph a diagnostic site inside the subject. Reduce the blur of the captured image due to the movement of the subject,
The present invention relates to an X-ray television device capable of preventing re-imaging due to an imaging error.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional X-ray television apparatus of this type includes a fluoroscopic imaging table 2 on which a subject 1 is laid, and an X-ray An X-ray tube 3 for emitting X-rays, an X-ray detector 4 disposed opposite to the X-ray tube 3, and configured to receive a transmitted X-ray image of the subject 1 and convert it into an optical image;
An imaging device 5 for taking an optical image from the X-ray detector 4 and converting it into an electric signal, a control circuit 6 for controlling the operation of the imaging device 5, and an image signal from the imaging device 5 And an image display device 7 for displaying. In FIG. 5, reference numeral 8 denotes a distributor for distributing the output optical image of the X-ray detector 4 to the imaging device 5, and reference numeral 9 denotes an X-ray high-voltage generator for supplying a high voltage to the X-ray tube 3. , Reference numeral 10 denotes an X-ray generation switch for starting X-ray generation. The X-ray detector 4 specifically includes an X-ray image intensifier (hereinafter referred to as “X-ray I.
I. "), and the imaging device 5 is a CCD camera.

Then, by operating the X-ray generation switch 10,
Activate X-ray generation and use X-ray high voltage generator 9
A high voltage is supplied to the X-ray tube 3, and FIG.
As shown in the figure, X-rays are emitted for only one predetermined imaging time t.
Then, the subject 1 is irradiated. The X-ray image transmitted through the subject 1 is
The image is converted into an optical image by an X-ray detector 4 comprising X-rays I.I.
Imaging by a CCD camera via the distributor 8
The light enters the device 5. This CCD camera 5 is
Control signal S from the control circuit 6 for controlling the ₁By
Is controlled, and as shown in FIG.
All the time, the image storage mode is set, and the X-ray image being captured is stored.
Stack. When the photographing is completed, the CCD camera 5
As shown in (c), the images accumulated during the photographing time t are obtained.
Read out the image and output image I₀Out to the image display device 7 as
Power.

[0004]

However, in such a conventional X-ray television apparatus, the CCD camera as the image pickup device 5 accumulates all images during one photographing time t and terminates photographing. Since the image is read out once at a time, the blur of the captured image due to the movement is small when the single imaging time t is short, but when the imaging time is long (80 ms or 100 ms or more) as in, for example, gastric imaging. However, blurring of the photographed image becomes large due to the movement of the subject during the photographing time. As described above, when the blur of the captured image becomes large, the image is not used for diagnosis, an imaging error occurs, and it may be necessary to take another image. In this case, the subject is restrained for a long time, and the X-ray exposure dose increases.

In view of the above, the present invention has been made to address such a problem and to reduce blurring of a photographed image due to movement of a subject even when the photographing time is long, thereby preventing re-imaging due to a photographing error. It is an object of the present invention to provide an X-ray television device capable of performing the following.

[0006]

In order to achieve the above object, an X-ray television apparatus according to the present invention comprises a fluoroscopy table on which a subject rests, and X-rays applied to the subject on the fluoroscopy table. An X-ray tube that emits light, an X-ray detector that is disposed opposite to the X-ray tube, enters a transmitted X-ray image of the subject, and converts the X-ray image into an optical image. An X-ray television device comprising: an imaging device that converts the image into an electric signal; a control circuit that controls the operation of the imaging device; and an image display device that inputs and displays an image signal from the imaging device. The imaging device is controlled by the control circuit.
It is assumed that a plurality of images are output in time series during the shooting, and the output side of the imaging apparatus detects motion of the plurality of images and reduces motion blur of the images due to the motion. Means are provided.

Further, the image pickup device is an interline transfer type or frame interline transfer type CCD camera.

Further, the motion blur correcting means detects the magnitude of the motion of the subject from the difference between the images before and after the plurality of images, and does not add the image with the large motion, and adds the image with the small motion. This is a motion-compensated recurable filter that adds images and reduces motion blur.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an X according to the invention.
It is a block diagram showing an embodiment of a line television device. This X-ray television apparatus irradiates a subject with X-rays to see through and photograph a diagnostic site inside the subject.
As shown in FIG. 1, a fluoroscopic imaging table 2, an X-ray tube 3, an X-ray detector 4, an imaging device 5, a control circuit 6, and an image display device 7 are provided. Is provided.

The fluoroscopic imaging table 2 lays the subject 1 on a top plate, and the top plate slides in the body axis direction of the subject 1 and moves up and down as a whole. . X
The X-ray tube 3 emits X-rays to the subject 1 on the fluoroscopy table 2, and is supplied with a high voltage from the X-ray high voltage generator 9. The X-ray detector 4 is disposed to face the X-ray tube 3 with the subject 1 on the fluoroscopy table 2 interposed therebetween, and receives the transmitted X-ray image of the subject 1 and converts it into an optical image. Specifically, it comprises an X-ray image intensifier (hereinafter, referred to as “X-ray II”).

The imaging device 5 captures an optical image from the X-ray detector 4 and converts it into an electric signal.
It consists of a D camera. The imaging device 5 is connected to the X-ray detector 4 via a distributor 8. The control circuit 6 controls the operation of the imaging device 5 and includes, for example, a timing control signal generator. The image display device 7 receives an image signal from the image pickup device 5 and displays the image as an image, and includes, for example, a television monitor. In FIG. 1, reference numeral 10 denotes an X-ray generation switch for starting X-ray generation.

Here, in the present invention, the imaging device 5 outputs a plurality of images in a time series during one photographing operation under the control of the control circuit 6.
The motion blur correction means 1 detects the motion of the plurality of images and reduces the blur of the image due to the motion.
1 is provided.

The image pickup device 5 is specifically an interline transfer type or frame interline transfer type CCD camera. This interline transfer type or frame interline transfer type CCD camera is capable of emitting X-rays from the X-ray tube 3 and continuously outputting optical images from the X-ray II as the X-ray detector 4 even when the X-rays are output. A plurality of images can be read out in chronological order without image degradation during shooting.

The motion blur correction means 11 calculates the difference between the images before and after the plurality of images input from the imaging device 5, and if the difference is large, the movement of the subject 1 is large. If the difference is small, the motion of the subject 1 is detected as small, and the motion is detected. If the motion is large, the image is not added. If the motion is small, the image is added, and motion blur is reduced. It is a type of recursive filter. As shown in FIG. 1, an example of the internal configuration of the recursive filter of the motion compensation type is an A / D converter 12 for digitizing an image signal from the imaging device 5 and an input from the A / D converter 12. A subtractor 13 for subtracting new data to be processed and processing data (old data) read from a frame memory 16 to be described later, and a lookup table for inputting difference data from the subtractor 13 and generating a constant K. An adder 1 for adding the stored ROM 14 and data input from the ROM 14 to processing data (old data) read from a frame memory 16 to be described later;
5 and a frame memory 16 for storing output data from the adder 15 as processing data.

FIG. 2 shows an example of a table function of a look-up table for generating a certain constant K stored in the ROM 14. This table function is created so as to output data corresponding to the size of the difference data output from the subtractor 13, and when the difference data is small, it is regarded as noise and the value of the constant K is reduced, When the difference data is large, it is assumed that the subject is moving, and the value of the constant K is increased.

Next, the operation of the X-ray television apparatus configured as described above will be described with reference to FIGS. First, in FIG. 1, X-ray generation is started by operating an X-ray generation switch 10, and a high voltage is supplied to the X-ray tube 3 via an X-ray high-voltage generator 9. FIG.
As shown in (a), X-rays are emitted for a predetermined single imaging time t and irradiate the subject 1. The X-ray image transmitted through the subject 1 is converted into an optical image by an X-ray detector 4 composed of X-rays II, and enters an imaging device 5 composed of a CCD camera via a distributor 8. The CCD camera 5 has a control signal S ₁ from a control circuit 6 for controlling the overall timing.
Is controlled to output a plurality of images in time series during one shooting. At this time, as shown in FIG. 3 (b), and resets the frame memory 16 of the motion blur correction unit 11 by the reset signal S ₂ from the control circuit 6 prior to imaging, as shown in FIG. 3 (h) keep the reset value M _0.

Next, as shown in FIG. 3 (c), the control circuit 6 sends a read signal of the CCD camera 5, and, for example, four images are obtained at a timing obtained by dividing one photographing time t into four equal parts. Control to output in chronological order. First, at the first read timing, the output image I
₀ images A _1, as shown in FIG. 3 (d) is outputted as is inputted to the motion blur correction means 11. Then, the above image A
The signal of ₁ is supplied to the A / D converter 12 as shown in FIG.
In which digitized the data AD _1. It is still the first image data, since nothing in the frame memory 16 the data is not stored, it is stored as it is sent to the frame memory 16 as image data AD _1. This, as shown in FIG. 3 (i), processing the image O ₁ becomes in this timing, the O ₁ = AD _1. At this time, the data stored in the frame memory 16 when placed with M _1, the AD ₁ = M _1.

Next, at the second readout timing of the CCD camera 5, as shown in FIG.
₂ is output and input to the motion blur correction means 11. Then, the data AD ₂ are digitized by the A / D converter 12 as shown in FIG. 3 (e). The data AD ₂ (new data) output from the A / D converter 12 is input to the subtractor 13 and subtracted from the data M ₁ (old data) read from the frame memory 16. When the output of the subtracter 13 and B ₂ as shown in FIG. 3 (f), B ₂
= The AD ₂ -M _1. The data B ₂ is input to the ROM 14, the certain constant K determined from the look-up table is multiplied. When this output and C ₂ as shown in FIG. 3 (g), the _{C 2 = K (AD 2 -M} 1). This R
The data C ₂ output from the OM 14 is input to the adder 15 to read the data M 2 read from the frame memory 16.
₁ (old data) is added. Then, the calculation result is stored in the frame memory 16. This is shown in FIG.
As shown in (i), the processed image O ₂ becomes in this _{timing, O 2 = K (AD 2} -M 1) + M 1 become. At this time, when put data stored in the frame memory 16 and _{M 2, K (AD 2 -M} 1) + M 1 = M 2
Becomes

Thereafter, the same processing is performed, and the CCD camera 5
In the third readout timing of FIG.
As shown in (i), O ₃ = K (AD ₃ −M ₂ ) + M ₂ = M ₃ . At the fourth read timing, O ₄ = K (AD ₄ −M ₃ ) + M ₃ = M ₄ , as shown in FIGS. Then, the processed image O ₄ is sent to the image display device 7 as the output image I ₁ of the motion blur correction means 11 and displayed as a photographed image.

In the above case, the value of the constant K is determined by the relationship with the table function of the look-up table shown in FIG. 2, but when the fluctuation of data at a certain position in the image is small as shown in FIG. Is regarded as noise and the value of the constant K is reduced, and when the data fluctuates greatly, the value of the constant K is increased assuming that the subject moves. That is, when the difference data from the subtractor 13 is small, the difference data is regarded as noise, and the value of the constant K is reduced.
By increasing the old data (M ₁ , M ₂ , M ₃ ) stored in the subroutine, and when the difference data from the subtractor 13 is large, it is considered that the subject is moving, and the value of the constant K is increased. New data (AD ₂ , AD ₃ ,
AD ₄ ) is increased.

For example, when K = 0, it is regarded as noise, and the old data stored in the frame memory 16 is output as it is. When K = 1, it is determined that there is movement of the subject, and the new data input from the CCD camera 5 is output as it is. Further, K = 0.
In the case of 5, the old data stored in the frame memory 16 and the new data input from the CCD camera 5 are simply added and output. Accordingly, even if the subject moves during imaging, a moving portion of the image is detected and the images are not added as in the related art, so that blurring of the image due to the movement can be reduced.

In FIG. 1, the image pickup device 5 is an interline transfer type or frame interline transfer type CCD camera. However, the present invention is not limited to this. Other imaging means may be used as long as a plurality of images can be output in time series during the operation. Further, the motion-blur correction means 11 is a recursive filter of a motion correction type having an internal configuration shown in FIG. 1, but is not limited thereto, and may be a recursive filter of another circuit configuration.
Other blur correction means may be used as long as the motion of a plurality of time-series images can be detected and the blur of the image due to the motion can be reduced.

[0023]

The present invention has been configured as described above.
An imaging device that captures an optical image from an X-ray detector and converts it into an electric signal. A plurality of images are output in chronological order during a single capture under the control of a control circuit that controls the operation of the imaging device. The output side of the imaging apparatus is provided with a motion blur correction unit that detects the motion of the plurality of images and reduces blur of the image due to the motion, so that the subject moves during the imaging. However, since the moving portion of the image is detected and the image is not added as in the related art, blurring of the image due to motion can be reduced. Therefore, even if the imaging time is long, blurring of the captured image due to the movement of the subject can be reduced, and re-imaging due to an imaging error can be prevented. Therefore, it is possible to prevent the subject from being restrained for a long time and to prevent an increase in the X-ray exposure dose.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an X-ray television device according to the present invention.

FIG. 2 is a graph showing an example of a table function of a look-up table for issuing a certain constant K stored in a motion blur correction unit.

FIG. 3 is a timing chart for explaining the operation of the X-ray television device of the present invention.

FIG. 4 is a graph showing a temporal change of data at a certain position in a captured image.

FIG. 5 is a block diagram showing a conventional X-ray television device.

FIG. 6 is a timing chart for explaining the operation of a conventional X-ray television device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 subject 2 fluoroscopic table 3 X-ray tube 4 X-ray detector 5 imaging device 6 control circuit 7 image display device 8 distributor 9 X-ray high voltage generator 10 X-ray generation switch 11: Motion blur correction means 12: A / D converter 13: Subtractor 14: ROM 15: Adder 16: Frame memory

Claims (3)

[Claims] An X-ray tube that radiates X-rays to the subject on the fluoroscopic table;
An X-ray detector that is disposed opposite to the X-ray tube and that receives a transmitted X-ray image of the subject and converts the X-ray image into an optical image; an imaging device that captures an optical image from the X-ray detector and converts the optical image into an electric signal; In an X-ray television device comprising a control circuit for controlling the operation of the imaging device and an image display device for inputting and displaying an image signal from the imaging device, the imaging device is controlled by the control circuit. It is assumed that a plurality of images are output in chronological order during one shooting, and the output side of this imaging device includes:
An X-ray television apparatus, comprising: motion blur correction means for detecting motion of the plurality of images and reducing blur of the images due to the motion. 2. An X-ray television apparatus according to claim 1, wherein said imaging device is an interline transfer type or frame interline transfer type CCD camera. 3. The motion-blur correction unit detects a magnitude of the motion of the subject from a difference between images before and after the plurality of images,
3. The motion compensation type recurable filter according to claim 1, wherein a large motion does not add an image, and a small motion adds an image to reduce motion blur. Line television equipment.