KR970000757B1 - Circuit for horizontal interpolation in the digital television - Google Patents

Abstract

A horizontal interpolation circuit for a digital television which can enlarge the display area of a digital television is disclosed. The circuit includes a control part(14) for generating address data corresponding to digital image data near a horizontal interpolation place, providing the address data to a memory(10) in which video data sampled in a period T is stored. The control part(14) generates a re-sampling period T' according to an enlarge information of the user. The circuit includes a control ROM(16) for detecting a difference value(dx) of the sampling periods T and T', and a horizontal interpolation part(12) for adding vector values which is obtained by applying the difference value(dx) to a SINC function to the SINC function, thereby outputting the re-sampling period T'.

Description

Digital TV's Horizontal Interpolation Circuit

1 is a sampling example performed in order to store a video signal in a frame memory in a conventional digital television.

2 is a diagram illustrating a conventional method when a digital image sampled and stored as shown in FIG. 1 is enlarged twice.

3 is an example of a screen displayed when the screen is enlarged in the manner illustrated in FIG.

4 is a block diagram of a digital television having a horizontal interpolation circuit according to the present invention.

5 is a diagram illustrating horizontal interpolation made in the horizontal interpolation unit shown in FIG.

* Explanation of symbols for main parts of the drawings

10: memory 12: horizontal interpolation unit

14: control unit 16: control ROM (ROM)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sequential scanning digital television, and more particularly, to a horizontal interpolation circuit used for screen magnification in digital television.

In general, sequential scanning television divides the radix field and the even field to express an image of one frame.

In such a progressive scan type television, a screen magnification function is used to enlarge a desired portion to a desired size.

For example, the screen magnification function proposed by the conventional sequential scanning TV is adopted by ID-TV (Model-300IDI) sold by Toshiba, Japan. It is intended to enlarge the screen. That is, when the composite video signal is sampled at a predetermined sampling frequency (4fsc) as shown in FIG. 1, and then quantized to a predetermined bit and stored in the frame memory, the area (3a) of FIG. 3 is doubled. If the pixel data ((a) to (d) and (f) to (i)) read from the frame memory are repeatedly transmitted two times horizontally and vertically as shown in FIG. As shown in Fig. 2), the same pixel is repeatedly scanned two times horizontally and two times vertically, thereby doubling the desired portion.

However, when the screen is magnified, the distance between the pixels (for example, between (a)-(b) and (a)-(b)) also doubles, so that the boundary between the pixels becomes noticeably clear ( Block) phenomenon has caused a problem that the image quality is reduced.

Accordingly, an object of the present invention is to provide a horizontal interpolation circuit of a digital television for horizontal interpolation to obtain data with a resampling period determined according to a horizontal magnification ratio in order to solve the above problems when the screen of a predetermined area is enlarged in a digital television. have.

The horizontal interpolation circuit according to the present invention is horizontal in order to obtain data at a resampling period (T ′) determined according to the horizontal magnification ratio when a screen is enlarged in a digital television having a memory for storing digital image data sampled at a T period in units of frames. In a circuit for interpolation, an address for reading digital image data of a position adjacent to a horizontal interpolation position among digital image data stored in a memory by an enlarged area information applied from an operator when a screen is enlarged is applied from an operator. A control unit for generating resampling period (T ') information calculated based on the enlargement ratio information; A control ROM for detecting a difference value dx between the resampling period T ′ and the sampling period T provided from the control unit; When a plurality of digital image data is transmitted from the memory by an address generated by the controller, each displacement obtained by generating a SINC function for each transmitted digital image data and applying a difference value (dx) to each generated SINC function And a horizontal interpolation unit 12 for outputting data of the resampling period T 'by horizontal interpolation processing of adding values.

Hereinafter, exemplary embodiments will be described in detail with reference to FIGS. 4 and 5.

4 is a block diagram of a digital television having a horizontal interpolation circuit according to the present invention, which includes a memory 10 for storing frame-by-frame digital image signals sampled and quantized as shown in FIG. Generates an address of digital image data adjacent to a position to be horizontally interpolated among the digital image data stored in the memory 10 based on the information, and resampling period T 'by the ratio information. Control ROM 16 for calculating and generating a control ROM 16 for detecting a difference value dx between the resampling period value T 'provided from the controller 14 and the preset sampling period value T, the control ROM And a horizontal interpolation unit 12 for performing horizontal interpolation processing on a plurality of digital image data transmitted from the memory 10 by using the difference value dx provided in (16).

5 is a diagram illustrating horizontal interpolation according to the present invention.

Next, the operation of FIG. 4 will be described with reference to FIG. 5.

First, the magnification area information applied to the control unit 14 is coordinate information of an area to be magnified in one frame image, and the magnification ratio information is designated by the operator as the magnification factor information desired by 2, 3, or other multiples. Can be. In this way, when the enlarged area information and the enlarged ratio information are applied according to the operator's point, the control unit 14 calculates the horizontal contrast ratio, so that the resampling period is T 'as illustrated in FIG. 5. The abnormality is referred to as T '), and the position to be horizontally interpolated (it is n as illustrated in FIG. 5) by the detected resampling period T' and the enlarged area information. When the position to be horizontal interpolated is detected, one of the digital image data stored in the memory 10 in synchronization with the horizontal synchronization signal H and the reference clock signal provided from the synchronization detecting circuit (not shown) is adjacent to the horizontal interpolation position. While transmitting the address signals (vertical and horizontal addresses VA and HA) for reading the digital image data (as illustrated in FIG. 5, m, p, and r correspond to this), the detected resampling period T Information is transmitted to the control ROM 16.

When the resampling period (T ') information is applied from the control unit 10, the control ROM 16 is a pre-stored resampling period (T as illustrated in FIG. 5, referred to as T for convenience of description below). And difference value (dx = T-T ') is detected, and the detected difference value is transmitted to the horizontal interpolation section 12.

The horizontal interpolation unit 12 outputs the resampled data by horizontally interpolating digital image data of the m, p, and r positions transmitted from the memory 10. The horizontal interpolation unit 12 will be described in detail with reference to FIG. same. That is, when m, p, r digital image data is transmitted from the memory 10, the horizontal interpolation unit 12 converts each SINC function to m ', p', r 'as shown in FIG. Get together. The SINC function is defined as Equation 1.

[Equation 1]

SINCx = SIN πx / πx

Thus, the displacement value corresponding to the position of n to be resampled is obtained by applying the dx value provided from the control ROM 16 to the SINC function for m, p, and r. As shown in (B) of FIG. 5, the displacement value is (a, b, c), where the displacement a is the dx position value on the SINC function of the p digital image data, and b is the m digital image data. The dx position value on the SINC function, and c is the dx position value on the SINC function for r digital image data.

The displacement values a, b, and c obtained in each SINC function are added together, and the added result is output as resampled data n. By providing the resampled data by such horizontal interpolation processing, an image enlarged by T / T 'times larger than an image having the original sampling period T can be obtained.

As described above, according to the present invention, by using the data resampled by horizontal interpolation by the sampling rate conversion during screen magnification, the block phenomenon generated at the boundary when screen magnification is prevented.

Claims (1)

Circuit for horizontal interpolation in order to obtain data of resampling period (T ') determined according to horizontal magnification ratio in screen magnification in digital television equipped with memory 10 for storing digital image data sampled at T period frame by frame And generating an address for reading digital image data of a position adjacent to the horizontal interpolation position among the digital image data stored in the memory 10 according to enlarged region information applied from an operator when the screen is enlarged. A control unit 14 for generating the resampling period T 'information calculated by the enlargement ratio information applied from an operator; between the resampling period T' provided by the control unit 14 and the sampling period T; A control ROM 16 for detecting a difference value dx; When a plurality of digital image data is transmitted from the memory 10 by an address generated by the controller 14, an SINC function is generated for each transmitted digital image data, and the difference value is generated in each generated SINC function. and a horizontal interpolation unit 12 for outputting data of the resampling period T 'by horizontal interpolation processing of adding the respective displacement values obtained by applying (dx). .