KR19980024542U - Resolution converting device of display device using interpolation method - Google Patents

Abstract

The present invention relates to a method of converting a resolution when it is necessary to convert to a resolution different from an input image among display devices for receiving and displaying sequential image information composed of a video signal and a synchronization signal. An interpolator that calculates the value of the scan line to be interpolated by multiplying the weights, a LINE SWITCHER that selects only the required scan line among the interpolated scan lines, a line buffer that stores the value of the selected scan line, and an interpolation function. It consists of a controller that switches the switching order, selects the line buffer, stores the value, generates the clock, selects the buffer to output, and generates the output clock, and considers the interpolation method considering the frequency at each position to interpolate. By differentiation, nonlinear distortion of the image can be minimized, and simple interpolation can be used when high frequency image is input. Although the phenomenon may occur, the designed method can minimize the haze phenomenon, and it can easily cope with low frequency image and high frequency image by adjusting the interpolation value of the interpolation function, and it is easy to increase and decrease the number of scan lines. You can achieve the effect of interpolating the entire screen without using the frame buffer.

Description

APPARATUS FOR CONVERTING RESOLUTION USING A INTERPOLATION OF DISPLAY MONITORS

1 illustrates a display screen when a video signal having a different resolution is input to an XGA LCD monitor in use in the related art.

A) XGA mode is displayed on the monitor,

B) the drawing with VGA mode displayed on the monitor,

C) the drawing in which the SVGA mode is displayed on the monitor,

D) is the drawing in which the EWS mode is displayed on the monitor,

2 shows a method by repetition of a scanning line in a conventionally used method,

3 illustrates a method of interpolating at a constant ratio of values,

4 is a block diagram illustrating a method according to the present invention.

[Detailed description of the proposal]

[Purpose of design]

[Technical field to which the draft belongs and its prior art]

The present invention relates to an apparatus for converting a resolution of an LCD (Liquid Crystal Display: LCD) monitor, and more particularly, an image input from a display device that receives and displays sequential image information composed of a video signal and a synchronization signal. The present invention relates to a method of converting a resolution when it is necessary to convert to another resolution.

Currently, monitors use CRT (CATHODE RAY TUBE: CRT) a lot, but LCD has less volume and power consumption than CRT and can be attached to the wall. The use of LCDs in the back will be further expanded. In accordance with this trend, further improvement and research of LCD monitors are required.

The video cards and chips currently in use vary. The resolution may be divided into VGA (640 × 480), SVGA (800 × 600), XGA (1024 × 768), and EWS (S × GA) (1280 × 1024).

For example, the resolution of an LCD monitor being used in the past will be described using XGA (1024 x 768) as an example. The resolution of 1024 x 768 means that the number of pixels appearing horizontally on the monitor is 1024, and 768 lines are formed vertically.

When the XGA mode is input to the LCD monitor, the screen appears as a screen suitable for the user as shown in (a) of FIG. 1, but when the VGA mode (B) or SVGA mode (C) is input, the screen appears small on the monitor. . However, when the EWS mode is input, since the resolution is 1280 × 1024, only a part of the figure appears on the screen, as shown in FIG.

As such, the conventional LCD monitor supports only one of the single display mode, that is, the VGA mode. Therefore, when a video signal other than the mode set on the LCD monitor is input, the screen tends to be displayed larger or smaller in the user's view as described above.

Conventionally, in an apparatus for displaying an input signal composed of a combination of a video signal (R, G, B COLOR OR BLACK WHITE) and a synchronization signal, input of various modes (a combination of vertical / horizontal scan frequencies: hereinafter referred to as a mode) In order to improve the resolution of the signal, a method of increasing the scan line is used.

As a method of increasing the scanning line, there is a method of changing the number of lines by the vertical conversion method, and the method of repeating the scanning line and the method of interpolating at a constant ratio value.

First, the method of repeating the scanning lines will be described with reference to FIG. 2. When the number of scanning lines is N times, the first scanning line is repeatedly outputted with the same scanning line twice, and the second scanning line is one scanning line, and the third The scan line is represented by one scan line and the fourth scan line by one scan line.

That is, the process of outputting the video signal stored in the memory to the monitor reads the first scan line from the memory and outputs it twice to the monitor, reads the second scan line and outputs it, reads the third scan line, and outputs the fourth scan line. Read and print As a result, four scanning lines are represented by five scanning lines.

This process is repeated every four scan lines.

In addition, referring to FIG. 3, a method of interpolating at a constant ratio value is a method of outputting a proportional value of two scan lines adjacent to the scan line to be output, for example, A, B, C, and D scan lines. E, F, G, H, I This is a method of making five scanning lines.

As shown,

E = 1 * A

F = 3/4 * B + 1/4 * A

G = 2/4 * C + 2/4 * B

H = 1/4 * D + 3/4 * C

I = 4/4 * D

However, the following problem occurs in the method by the repetition of the scanning line described above.

First, since the number of nonlinear scanning lines is locally increased, distortion of the image occurs.

For example, when the horizontal lines are composed of several horizontal lines of the same thickness, the horizontal lines of different thicknesses are used in the converted image.

In addition, a problem arises in the method of interpolation with a constant ratio value. Since a new scan line is generated by applying a plastic ratio to the values of two adjacent scan lines, the image as shown in the picture is smoothly determined, but there are many high-frequency components in the vertical direction. When applied to the MODE, there is a side effect of blurring the boundary line, and both methods have a problem that they cannot be used where the scanning line should be reduced.

[Technical Challenges to be Done]

Therefore, in order to prevent nonlinear distortion caused by the insertion of non-uniform scanning lines of the prior art and to compensate for SHARPNESS reduction caused by the interpolation method of simple proportional scanning lines, an interpolation function according to simple proportional image information frequency Its purpose is to provide a way to increase or decrease the number of scan lines using.

[Composition and Action of Design]

4 shows a block diagram according to the configuration of the present invention, an interpolator 10 for calculating a value of a scan line to be interpolated, a LINE SWITCHER 20 for selecting only a required scan line among interpolated scan lines, and a value of a selected scan line. Each line buffer (LINE BUFFER) 30, which stores an interpolation function, switches the switching order of the LINE SWITCHER, selects a line buffer, generates a clock to store the value, and selects a buffer to output. The controller 40 is configured to generate an output clock.

Referring to the operation of the block diagram configured as described above are as follows.

F (freq, α, β) is an interpolation function considering the frequency characteristics of the video around the interpolation point.

If high frequency,

α (x) = -1 / {1 + EXP [-A * (x-(x2-x1) / 2)]} + 1

β (x) = 1 / {1 + EXP {A * (x-(x2-x1)]}

If the curse pie,

α (x) = -1 * (x-x1) / (x2-x1) + 1

β (x) = (x-x1) / (x2-x1).

Where A 0, where x is a variable between two scan lines X (n) and X (n + 1).

The value interpolated by the interpolation function F (freq, α, β) between the two mth values of the two scan lines X (n) and X (n + 1) is L (i, m), I = 0, 1, .. ..., k-1. k is equal to the number of values to be output as interpolation between two points.

L (i, m) becomes y (j, m) by the switching function S (n, i, j) and is stored in the line buffer designated by WEB (n, j) according to WR-CLK. The value of the line buffer specified by REB (n, j) is output to OUTPUT (m) in accordance with RD-CLK.

The number of horizontal scanning lines during one vertical scanning is the number of scanning lines of the input signal, and is used as a function of selecting the scanning lines to be interpolated by comparing the number of scanning lines of the detected input signal with the number of scanning lines to be output.

S (n, I, j) is a function that converts the I-th value into the j-th line buffer (LINE BUFFER) among interpolated values, WEB (n, j) is a function that specifies a buffer to store the value, and REB (n, j) is a function that specifies the function to output, and the input buffer and output buffer are designated sequentially by the storage speed (frequency of WR-CLK) and output speed (frequency of RD-CLK). A plurality of buffers may be designated according to the number of scanning lines to be interpolated.

[Effect of design]

Therefore, by using the interpolation method devised in the present invention, the nonlinear distortion of the image can be minimized by changing the interpolation method in consideration of the frequency at each position to be interpolated, and using simple interpolation when a high frequency image is input. Although the phenomenon can occur, the designed method can minimize the haze phenomenon, and by simply adjusting the A value of the interpolation function, it can easily cope with the low frequency image and the high frequency image, and it is easy to increase and decrease the number of scanning lines. In addition, it is possible to obtain an effect of interpolating the entire screen without using a frame buffer.

Claims (1)

An interpolator that calculates the value of the scan line to be interpolated by multiplying the input scan line by a weight, a LINE SWITCHER that selects only the required scan line among the interpolated scan lines, a line buffer for storing the value of the selected scan line, and an interpolation function And converts the switching order of LINE SWITCHER, selects the line buffer, generates the clock to store the value, selects the buffer to output, and converts the number of scan lines of the input image. Device.