JPH01273487A - Digital x-ray device - Google Patents

Abstract

PURPOSE:To improve the sense of after image and to display a high definition picture by avoiding application of a recursive filter to a low frequency component. CONSTITUTION:After a video signal or a picture is digitized by an A/D converter 11, a two-dimension smoothing processing is applied by a smoothing circuit 12 and an output (a) becomes a picture of only low frequency component of a fluoroscopic picture. On the other hand, the output of the A/D converter 11 is inputted to a subtractor 13 together with the output of the smoothing circuit 12 and both the outputs are subtracted. The output (b) of the subtractor 13 is a picture of a high frequency component only of the fluoroscopic picture, inputted to a recursive filter 14, after noise component is decreased and the result is a picture (c) of the edge part only and inputted to an adder 15. The adder 15 adds the image (a) of the low frequency component only and the image (c) of the edge part only with reduced noise. Thus, the sense of after image is improved and the high definition picture is displayed.

Description

[Detailed description of the invention] [Industrial application field] INDUSTRIAL APPLICATION This invention is utilized in the field of digital image processing.

The present invention relates to a digital X-ray apparatus, and more particularly to a digital X-ray apparatus in which noise reduction processing is performed on a digital X-ray fluoroscopic image obtained through an image intensifier and an X-ray television camera.

[Prior Art] Conventionally, noise in an image has been reduced by image processing in which the image is passed through a recursive filter to give an afterimage effect.

[Problems to be Solved by the Invention] It is known that an X-ray fluoroscopic image obtained through an image intensifier (1,1,) and an X-ray television camera (XTV) contains a lot of quantum noise.

The video signal obtained from XTV is digitized and noise reduction is often performed using a recursive filter method, but although the recursive filter is effective for still images, it produces a feeling of afterimage for moving images. , it is not necessarily an effective method.

An object of the present invention is to provide a digital X-ray apparatus that can display clear images with improved afterimage feeling even when a recursive filter is applied to moving images or continuous images.

[Means for Solving the Problems] The above-mentioned purpose is to generate an image of low frequency components and an image of high frequency components for each frame of continuous digital X-ray images obtained through an image intensifier and an X-ray television camera. a separation circuit section that separates the image into two, a filter circuit section that applies a recursive filter to the high frequency component image, and an addition circuit section that adds the separated low frequency component image and the high frequency component image that has passed through the filter circuit section. This is achieved by:

1 action] A perspective image that consists of an image containing only noise and edge parts (particularly separates the high frequency components of the elephant, applies a recursive filter only to this, and creates an image in which the noise part is removed and the edge parts are left) , is added to the low frequency component image that is not subjected to a recursive filter to form a display image.

[Example] A preferred embodiment of the invention will be explained based on the drawings.

FIG. 1 is a block diagram of a noise reduction processing section showing one embodiment thereof, and FIG. 2 is an internal circuit diagram of the cursive filter 14.

The illustrated video signal or image passes through an image intensifier and an X-ray television camera (XTV) (not shown), is digitized by an A/D converter 11, and then converted into a two-dimensional signal by a smoothing circuit 12. Smoothing processing is performed.

The output a of the smoothing circuit 12 is an image containing only low frequency components of the fluoroscopic image. On the other hand, the output of the A/D converter 11 is input to the subtracter 13 together with the output of the smoothing circuit 12, and the i7! The calculation is done.

The output of the subtractor 13 is separated from the low frequency component image, and is an image containing only the high frequency components of the perspective image, that is, noise and edge portions.

The output signal is input to a recursive filter 14, and after noise components are removed, it becomes an image C containing only the edge portion, and is input to an adder 5.

The Calo calculator 15 adds the image A containing only the low frequency component and the image C containing only the edge portion where noise has been removed.The addition result is converted into an analog by the D/A converter 16 and displayed on a monitor (not shown). Is displayed.

Note that, inside the recursive filter 14, as illustrated in FIG.
1-1/K] consists of an arithmetic unit 14b, an adder 14C, and a frame memory 14d.

[Conclusion] In general, the movement of an object has a large movement of low frequency components. In the present invention, the motion is followed without applying a cursive filter to the low frequency components, and compared to the conventional case where a cursive filter is applied to all image components, the afterimage feeling is reduced. Improved and clearer images are displayed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a noise processing section showing one embodiment of the present invention, and FIG. 2 is a diagram illustrating an internal circuit of a recursive filter according to the present invention. 11 is an A/D converter, 12 is a smoothing circuit, 13 is a subtracter, 14 is a recursive filter, 15 is an adder, 16 is a D
/A converter. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] 1. A separation circuit unit that separates the continuous digital X-ray images obtained through the image intensifier and the X-ray television camera into low-frequency component images and high-frequency component images for each frame; A digital X-ray apparatus characterized by comprising a filter circuit section that applies a recursive filter to an image, and an addition circuit section that adds the separated low-frequency component image and the high-frequency component image that has passed through the filter circuit section. .