JPH01274571A - Picture quality improving device - Google Patents

Abstract

PURPOSE:To obtain a sharp picture with less effect due to after image by providing plural frame memories, accumulating picture data by plural patterns and applying arithmetic means. CONSTITUTION:A control signal of frame memories 1 to 4 is fed sequentially for each frame and plural frames of newest picture data, e.g., 4 frames are always stored in the memories 1 to 4. The picture data corresponding to the same location among the frame pictures are read simultaneously from the memories 1 to 4 by four patterns and added by an adder 5. The added data are averaged into 1/4 by a divider 6. The memories 1 to 4 act like 4-stage shift registers using the frame period as the clock as to the input picture data and store the newest picture data at all times, then the picture quality improving effect is excellent. Moreover, since arithmetic mean is applied, a sharp picture with less effect due to after image is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] In television (hereinafter referred to as TV) image processing, especially in X-ray TV image processing, random noise generated by X-ray quantization noise is mixed, and one image becomes unclear. Conventionally, methods for improving image quality have been proposed.

The present invention relates to an improvement of an image quality improvement device for X-ray TV images.

[Summary of the invention]

A conventional X-ray TV image quality improvement device accumulates one image data in a frame memory for one screen.

Since the method uses averaging, previously stored image data remains forever, and the influence of afterimages becomes a problem when processing image data of fast-moving subjects. Since the present invention performs averaging from only the image data sequentially stored in the frame memory for the number of frames (N screens), image data for N screens or more does not remain, resulting in ideal image quality with less influence of afterimages. Improvements can be made.

[Conventional technology]

Conventionally, as a method for improving the image quality of TV images, processing as shown in equation (1) below has been performed.

Note that AT: Frame memory image de9° at time T BT:
Input image data at time T, AT]: frame memory image data from one frame before, N: constant (N== 21,
n is an integer).

Here, the above equation (1) can be rewritten as linear.

In this method, the frame image data before the current time is 1-
According to an exponential rule with a coefficient of 1, the influence of the previous image on the averaged image is made smaller than that of the subsequent image in one hour.

The conventional image quality improvement device described above accumulates image data for 8 screens in the frame memory for 1 screen and performs averaging, so previously stored image data remains forever and there is no movement. In the case of images of fast-moving objects, the influence of afterimages becomes a problem.

[Problem to be solved by the invention]

Figure 2 shows the video level of the input video signal from 100% to 0%.
3 is a graph showing the afterimage characteristics of the image quality improvement device when the image quality improves. In FIG. 2, the horizontal axis represents time in the number of frames, and the vertical axis represents the output video level in percentage. Conventional characteristics are shown in graph a (constant N: 4), and characteristics of the present invention are shown in graph b (number of memories = 4).

The present invention aims to improve the afterimage characteristics of an image quality improvement device from graph a to graph b, and to reduce the influence of afterimages.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a plurality of frame memories (for 8 screens), each frame memory sequentially stores frame image data every N frames, and each frame memory sequentially stores frame image data every N frames. By sequentially rewriting the image data.

It is configured so that averaging processing of new image data for only 8 screens can always be performed in real time.

[Effect]

As a result, the plurality of frame memories (for 8 screens) act on input image data like an N-stage shift register using the frame period as a clock.

To always store the latest 8 screens worth of image data.

The S/N improvement as an image quality improvement effect is JT, and the influence of afterimages can be suppressed to N frames at most. [Example] Figure 1 shows an example of the present invention, and the number of additions of frame image data is 4 times. 8 is an A/D converter, 1 to 4 are frame memories, 5 is an adder, 6 is a 1H divider, and 7 is a D/A converter. In FIG.
The input video signal is converted into binary image data by the A/D converter 8, and is given to the frame memories 1 to 4 as common input data.

By sequentially sending the write control signal of each frame memory one frame at a time (Figure 1 shows a rotary switch configuration that switches at frame cycles), each frame memory 1 to 4 always has the latest information. Image data for four frames is stored. 7 RAM memory 1 to 4 for these 4 screens
From there, image data corresponding to the same position between each frame image is simultaneously output and added by an adder 5. The added data is added to a 1H divider 6 and averaged to 1/4.
Image quality is improved. The D/A converter 7 is.

This averaged binary image data is converted into a TV video signal, resulting in an output video level with improved image quality for display on a TV monitor or the like.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to obtain clear images with little influence of afterimages in the image quality improvement device. This is particularly effective when a moving subject such as an organ is monitored on a monitor TV in the XtlTVINl image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the device of the present invention, and FIG.
The figure is a graph showing afterimage characteristics. 1 to 4: Frame memory, 5: Adder, 6: 1C divider. 11 figures

Claims (1)

[Claims] 1. In an image quality improvement device that is equipped with a frame memory that stores television video signals and a calculation unit, and that reduces random noise by averaging image data between frames, the latest multiple frames (N screens) are always displayed. It is characterized by a configuration consisting of a frame memory for N screens that sequentially stores image data, and a circuit that reads out image data corresponding to the same position between the stored frame images and reduces random noise by averaging processing. Image quality improvement device.