KR19980016791A - Luminance / Color Signal Separation Device by Data Compression - Google Patents

Abstract

1. The technical field to which the invention described in the claims belongs:

An apparatus for separating luminance / color signals in an NTSC composite image processing apparatus.

2. The technical problem the invention is trying to solve:

A luminance / color signal separation device for compressing and storing a composite video signal is provided.

3. Summary of the Solution of the Invention:

A differential pulse code modulator for differentially modulating a composite video signal, means for detecting the start of one line of the composite video signal based on a synchronization signal, and a variable length code table for outputting the differential pulse code modulator A variable length code data generation unit for outputting data and inserting a signal indicating the start of the first line into the corresponding region of the compressed data when the first line is detected, and a plurality of memories to which an output of the previous memory is applied as an input of a later memory; And a delay unit for outputting compressed data having different time differences, a decoder for decoding the delayed compressed data and outputting one line data before and after 1H based on the first line start detection, and luminance from the decoded one line data. And a luminance / color signal separator for detecting and outputting a signal and a color signal.

4. Important uses of the invention:

Used to compress and store composite video signals when separating luminance and color signals.

Description

Luminance / Color Signal Separation Device by Data Compression

The present invention relates to an apparatus for separating luminance signal / color signal (hereinafter referred to as Y / C) of an NTSC composite video signal, and more particularly, to an apparatus for compressing and storing an input composite video signal.

Typically, the National Television System Committee (NTSC) signal may be compatible with color signals and monochrome signals. The NTSC signal is divided into a luminance signal Y representing a contrast, a color signal C representing a color, and a synchronization signal serving as information for transmitting the position and timing of the screen. The three signals are synthesized so as not to affect each other, and the color signal 3.58 MHz is inserted inside the frequency bandwidth of 4.2 MHz of the luminance signal. Therefore, a process of separating the luminance signal and the color signal is necessary.

1 is a block diagram illustrating a Y / C separation apparatus in conventional NTSC composite video signal processing. Hereinafter will be described in detail with reference to FIG.

First, in NTSC, 1H on the monitor is 910 pixels. Accordingly, the capacity of the first line memory 2 and the second line memory 4 is 910 pixels x 8 bits to store one line. The Y / C separation unit 112 inputs the composite video signal and the outputs of the first line memory 2 having one line delayed from the composite video signal and the second line memory 4 having one line delayed from the first line memory 2. Outputs the luminance signal and the color signal separately. That is, when the L-1 line of the composite video signal is applied to the Y / C separator 112 in time, the data of the L line from the first line memory 2 and the data of the L + 1 line from the second line memory 4 are applied. Is applied to the Y / C separator 112. The Y / C separation unit 112 implements the adder and the subtractor using the condition that the phase of the color signal is inverted every 1H and the signals before and after the 1H are similar. Thus, the adder and the subtractor input, subtract, and add a composite video signal of L-1, L, L + 1. Since the color signal is reversed around 1H, and the luminance signal is in phase before and after 1H, the adder adds only the luminance signal by removing the reversed color signal and outputs only the color signal by eliminating the luminance signal of the in phase. In this manner, the luminance signal and the color signal are separated and output.

As described above, the conventional technology has a problem that the number of line memories is limited due to hardware size and economic problems, so that separation efficiency is lowered.

Accordingly, an object of the present invention is to provide a device for separating luminance / color signals by data compression for compressing and storing the composite image signal in order to delay the composite image signal to be separated into luminance / color signals around 1H.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a Y / C separation apparatus in conventional NTSC composite video signal processing.

2 is a block diagram of a Y / C separation apparatus using data compression in NTSC composite video signal processing according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that like elements in the figures represent like reference numerals wherever possible. It should also be noted that in the following description of the embodiments, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to obscure the subject matter of the present invention.

As used herein, the term "pre-memory" refers to a memory that is preceded in order in a plurality of memories, and the term "memory memory" refers to a memory located next to the preceding memory.

2 is a block diagram of a Y / C separation apparatus using data compression in NTSC composite video signal processing according to an exemplary embodiment of the present invention. Hereinafter, a description will be given with reference to FIG. 2.

A differential pulse code modulation unit (hereinafter referred to as DPCM (Differential Pulse Code Modulation)) 22 inputs a composite video signal and pulse code modulates the difference between the data of the previous pixel and the data of the rear pixel under the control of the following control unit 24. In this case, since the composite image signal is a horizontally similar image, the difference between the front and rear pixel data is not large. Variable Length Code (hereinafter referred to as VLC) Table 28 includes compressed data for output data of the DPCM 22. The controller 24 inputs the horizontal synchronization signal H-SYNC to control the following one-line start data generator 30 after a predetermined time has elapsed. The one-line start data generator 30 outputs one-line start data indicating the start of one preset line under the control of the controller 24.

A variable length code data generation unit (hereinafter referred to as VLC) 26 executes a Huffman code, accesses the VLC table 28 by inputting the output of the DPCM, and accesses the compressed data. In addition, the VLC 26 inserts the first line start data into a corresponding region of the compressed data to be applied. That is, when the compressed data is the start of one line, the first line start data is inserted before the compressed data. The delay unit 100 includes first, second, and third memories 32, 34, and 36 of the first-in, first-out structure. In the embodiment of the present invention, three memories are used, but three or more memories may be implemented. The first memory 32 inputs the output of the VLC 26. The second memory 34 inputs the output of the first memory 32. The third memory 36 inputs the output of the second memory 34. Thus, the output of the delay unit 100 is an output of the first memory 32, an output of the second memory 34 delayed by a predetermined delay from the output of the first memory 32, and an output of the third memory 36 delayed by a predetermined delay than the output of the second memory 34. Is done. The decoder 38 performs a decoding function as opposed to the VLC 26, and inputs the outputs of the first, second, and third memories 32, 34, and 36 to output in units of lines. The decoder 38 also outputs data L + 1, L, L-1 before and after 1H in units of one line based on one line start data. The Y / C separator 112 is the same as that of Fig. 1 and outputs a luminance signal and a color signal.

According to the above configuration, the composite video signal is compressed by DPCM 22 and VLC 26 and applied to the delay unit 100. At this time, the first line start data exists at the corresponding position of the output compressed data. The compressed data of one block unit input first is output by the third memory 36, and the compressed data of one block unit in the intermediate order is output by the second memory 34, and the compressed data of one block unit inputted last is 1 is output by memory 32. The decoder 38 decodes the compressed data of three block units output by the first, second, and third memories 32, 34, and 36, and outputs one-line data having a start difference before and after 1H by the one-line start data. do. Thereafter, the luminance signal and the color signal are separated and output by the Y / C separation unit 112.

As described above, the composite video signal is compressed and stored in a memory for adding or subtracting the composite video signal before and after 1H when the luminance / color signal is separated. This has the advantage that the data to be stored is reduced, so that more data is stored, and it is economical because the amount of memory can be reduced.

Claims (2)

An apparatus for separating luminance / color signals from composite video signals in an image processing apparatus, A differential pulse code modulator for differentially modulating the composite video signal, means for detecting the start of one line of the composite video signal based on a synchronization signal, and generating one line start data; and an output of the differential pulse code modulator. A variable length code for outputting compressed data using the variable length code table provided in advance, and inserting and outputting a signal indicating the start of one line based on the one line start data into a corresponding region of the compressed data A data generator and a plurality of memories to which the output of the previous memory is applied as an input of the later memory, and a delay unit for outputting compressed data having different time differences based on the memories, and decoding the output of the delay unit. A decoder for outputting one line data before and after 1H based on the one line start data; By entering the output of the decoder detects a luminance signal and color signal separating unit luminance / color signal by data compression, characterized by configured as an output luminance / color signal separating an an. The method of claim 1, And the first line start data is detected by a horizontal synchronizing signal.