JPS63300742A - Digital x-ray apparatus - Google Patents

Abstract

PURPOSE:To process a highly detailed X-ray image high in spatial resolving power at a high speed in real time, by processing image data at every plural pixels. CONSTITUTION:The X-ray image data from a television camera 4 is applied to the A/D converter 6 of an image processor 5 and inputted to an operational processor 7 at a unit of two adjacent pixels from the A/D converter 6. The image data processed at the two-pixel unit in this operational processor 7 is inputted to a scanning conversion memory 8 and the image data sent out at a 16-pixel unit from the scanning conversion memory 8 is sent to a monitor television apparatus 10 through a D/A converter 9.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an X-ray device, and in particular to digital radiography (DR), which digitizes and handles X-ray images.
This invention relates to a digital X-ray device that performs.

[Conventional technology]

The currently widely used X-ray equipment uses a film-screen system for X-ray imaging, but while it has excellent resolution, the fixed film image makes it difficult to perform gradation processing and spatial frequency. The disadvantage is that it is not adaptable to image processing such as image processing. Therefore, in recent years, D
R, a device has been developed. This method employs a film digital method, in which X-ray film is read and processed with a laser scanner, and a method that uses an imaging plate.

[Problems to be solved by the invention]

However, all of these methods mainly require a large amount of time to read the image, and the image cannot be displayed immediately after being photographed, resulting in a lack of immediacy. In addition, in the X-ray exposure process, these
Since it is exactly the same as the screen system, there is a limit to the image capture speed and the temporal resolution is low. An object of the present invention is to provide a digital X-ray apparatus that can process X-ray images with extremely high spatial resolution in real time at high speed.

[Means to solve the problem]

The digital X-ray device according to the present invention includes an X-ray tube, a large-diameter image intensifier, a television camera with a large number of scanning lines for photographing the output image of the image intensifier, and a television camera with a large number of scanning lines. It is equipped with an A/D converter that samples the video signal from the camera at multiple points for each scanning line and performs A/D conversion, and a digital image processing device that processes the digitized video signal for each plurality of pixels. Features.

[For production]

Image data with extremely high spatial resolution can be obtained by sampling a video signal from a television camera with a very large number of read scanning lines at multiple points for each scanning line and A/D converting it. However, when obtaining image data with such high spatial resolution, the amount of data for one screen becomes enormous, and the data output speed from the A/D converter also becomes extremely fast. and,
If this enormous amount of high-speed data is processed as it is, the burden on the digital image processing device will be too great.However, if the processing speed is not reduced, immediacy will be lost and temporal resolution will deteriorate. Therefore, by adopting a configuration in which digitized video signals are processed for each pixel, both the transmission speed and the processing speed can be reduced to less than half, and the burden on the digital image processing device does not increase significantly. High-resolution digital images can be processed at high speed in real time.

【Example】

In FIG. 1, X-rays irradiated from a microfocus X-ray tube 1 toward a subject 2 pass through the subject 2 and enter a large-diameter image intensifier (1, 1,) 3. The transmitted image is converted to a visible light image. This visible light image is input to the television camera 4, and a charge image corresponding to an X-ray transmitted image is formed on the turquoise surface of the image pickup tube. At this time,
In this television camera 4, charge image readout scanning on the imaging surface is performed in a non-interlaced manner, and whether a video signal is obtained □ or the charge image readout horizontal scanning line is scanned normally (N
The number of lines is about 2000, which is about four times that of the TSC method), and the scanning speed for one horizontal scanning line is 1/2 the normal speed, and the scanning time for one horizontal scanning line is twice the normal one. This results in a video signal at a rate of 3.75 frames per second. This video signal is sampled by the A/D converter 6 of the image processing device 5 at a sampling frequency of 20 MHz,
A at 2000 sampling points per horizontal scanning line
/D conversion is performed. Since there are a large number of sampling points per horizontal scanning line, the horizontal scanning speed is slowed down to ensure horizontal resolution as described above. In other words, the horizontal scanning speed is slowed down, and the sampling frequency is correspondingly lowered, thereby lowering the frequency band of the video signal and preventing electrical deterioration of the signal in the video signal amplification system, etc. . In this way, high spatial resolution digital image data of 7 trix of 2000×2000 images is converted into 3.7
Obtained at 5 frames/second. By the way, when obtaining such high spatial resolution image data, the limit of the spatial resolution of the image intensifier becomes a problem. This problem is cleared by placing the subject 2 away from the input surface of the image intensifier 3 as shown by the solid line and performing enlarged X-ray photography. The large-diameter image intensifier 3 is indispensable to substantially improve MTF due to enlargement and to secure a field of view against field of view limitations caused by enlargement. When performing enlarged X-ray imaging, the grid 13 is not needed because the scattered radiation is removed by the Gredel effect.
(or a removable attachment/detachment machine f*),
Efforts are being made to make effective use of X-rays. Note that when close-up imaging is performed with the subject 2 brought into close contact with the input surface of the image intensifier 3 as shown by the dotted line, the grid 13 is attached to the input surface of the image intensifier 3 as shown by the solid line. . This image data is obtained from the A/D converter 6 at a speed of 20 MHz, but if it were sent to the next processing unit 7 at the same speed, the hardware capability of the processing unit 7 would have to be extremely sophisticated. As shown in Figure 2, 16-bit one word data is divided into upper and lower parts, and the previous pixel data is stored in the upper part and the current pixel data is stored in the lower part. The two pixel data to be processed are handled together, and 2
Send in pixel units to reduce transmission speed by half (], OMHz)
Moreover, parallel processing is performed in units of two pixels inside the arithmetic processing bag M7, thereby lightening the hardware burden on the arithmetic processing unit 7 and reducing costs. In this arithmetic processing device 7, image processing such as recording using a built-in frame memory, gradation processing, spatial frequency processing, and inter-pixel calculation is performed in parallel in units of two pixels. The arithmetic processing unit 7 is controlled by a system controller 12 together with an X-ray generator 11 that applies high voltage to the X-ray tube 1 and the like. The output of this arithmetic processing device 7 is transferred to the scan conversion memory 8 in units of two pixels at a transmission rate of 10 MH2. The image data input to the scan conversion memory 8 is non-interlaced scanning at a rate of 3°75 frames/second, but even if it is displayed as is on the monitor television device 10, the frame rate will be too low. Because of this, the human eye sees only a flickering image. Therefore, the scan conversion memory 8
The scanning method and frame rate are converted using . In this embodiment, scan conversion memory 8
The image data of non-interlaced scanning method is 3.75.
It is written at a rate of 1 frame/second and interlaced read scanning is performed at a rate of 30 frames/second. The image data read from the scan conversion memory 8 is sent to the D/A converter 9 in units of 166 pixels. At this time, the data transmission rate is 10 MHz. The D/A converter 9 performs serial-to-parallel conversion on the image data sent with 166 pixels, converts it into analog data at a speed of 160 MHz, obtains an analog video signal, and sends this to the monitor television device 10. Therefore, in this monitor television device 10, the height and width are 2000 x 2000.
An extremely high-definition X-ray image with pixels of 30 frames per second will be displayed in real time at a frame rate of 30 frames/second using the interlaced scanning method.

【Effect of the invention】

According to the digital X-ray apparatus of the present invention, by processing image data for each plurality of pixels, it becomes possible to process high-definition X-ray images with extremely high spatial resolution in real time and at high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a diagram schematically showing a data structure. DESCRIPTION OF SYMBOLS 1... Microfocus X-ray tube, 2... Subject, 3... Large diameter image intensifier, 4... Television camera, 5... Image processing device, 6... A/ D converter, 7... Arithmetic processing unit, 8... Scan conversion memory, 9... D/A converter, 10... Monitor television device, 11... X-ray generator, 12... - System controller, 13...grid.

Claims (2)

[Claims] (1) An X-ray tube, a large-diameter image intensifier, a television camera with a large number of scanning lines that captures the output image of the image intensifier, and a video signal from the television camera. A/D that samples at multiple points for each scanning line and performs A/D conversion
A digital X-ray device comprising: a converter; and a digital image processing device that processes a digitized video signal for each pixel. (2) The digital X-ray apparatus according to claim 1, wherein the subject is placed away from the input surface of the large-diameter image intensifier.