SU1739505A1 - Apparatus for separating signals brightness and chromaticness - Google Patents

Abstract

The invention relates to television technology and can be used as part of the receiving equipment of the SECAM system. The purpose of the invention is to increase the mutual noise immunity of the luminance and chroma signals. The device for dividing the luminance and chroma signals contains filters 1, 6 low frequencies, block 2 delays per line, subtractors 3, 16, adders 4, 14, amplitude limiter 7, threshold element 8, electronic switch 9, band-pass filters 10, 17, notch filter 11, delay elements 12, 13, 15, block 18 delay, 1 Il.

Description

The invention relates to the technique of television and can be used as part of the receiving equipment of the SECAM system.

The purpose of the invention is to increase the mutual noise immunity of luminance and color signals.

The drawing shows an electrical block diagram of a device for separating luminance and color signals.

The device for separating luminance and color signals contains a first low-pass filter 1, a delay block 2 per line, a first subtractor 3, a second adder 4, an amplitude detector 5, a second low-pass filter 6, an amplitude limiter 7, a threshold element 8, an electronic switch 9, the first a band-pass filter 10, a notch filter 11, a first delay element 12, a third delay element 13, a first adder 14, a second delay element 15, a second subtractor 16, a second band-pass filter 17, a delay unit 18.

A device for separating luminance and color signals works as follows.

The full television (TV) signal (ep) of the current field arrives simultaneously at the inputs of the first low-pass filter 1, delay unit 18 (for the time t = t _n + y, where t _n and t _c are the field and line intervals of the first, band-pass filter 10 and the notch filter 11 through the first delay element 12 and to the first inputs of the first adder 14 and the second subtractor 16.

Using the delay unit 18, the first adder 14 and the second subtractor 16, the video signal is divided into luminance and color signals through the use of vertical spatial image correlation. However, this type of separation affects the quality of the reproduced image in areas where there is no correlation, and where there are rapidly moving parts in the image structure. In this case, the signals in neighboring fields become non-identical, which leads to the appearance of cross distortions,

It is proposed to detect sections of cross-distortion compensation violations to realize the separation of the line-to-line difference (SMR) signal corresponding to the current TV signal. Moreover, in order to eliminate the influence of the color signal on the SMR, the length of the spectrum of the TV signal (before isolating the SMR) is limited by the first low-pass filter 1 to a value of the order of 3.5 MHz. Next, the luminance signal of the current line (current field) is fed to the input of the delay unit 2 per line and to the first input of the first subtractor 3, the second input of which receives the brightness signal of the previous line (current field). At the output of the first subtractor 3, an SMR is formed corresponding to the current TV signal of the areas of compensation violation and the rapid movement of image details vertically. The detection of the parts of the moving parts of the current signal relative to tc held for a time ΐ = ΐ _π + y horizontally is carried out by comparing these signals in the second subtractor 16 (horizontal displacement decoder). The resulting displacement signal is passed through a second band-pass filter 17 (spectrum limitation from o; 1.5 to 3.5 MHz). The signals from the output of the first subtractor 3 and the second band-pass filter 17 are fed to the first and second inputs of the adder 4, respectively. As a result, a signal is generated corresponding to areas of compensation violation. Next, the signals from the output of the second adder 4 are sequentially fed to the inputs of the amplitude detector 5, the second low-pass filter 6, the amplitude limiter 7 and to the control input of the electronic switch (EP) 9 through the threshold element 8.

In cases where the modulus of the change signal (СМР or the signal from the horizontal displacement detector) exceeds a predetermined threshold, EP 9 is switched over. Thus, if at least one of the types of violation is manifested (sharp transitions of information vertically, fast movements vertically or horizontally ) the corresponding control signal connects the outputs of the device to the outputs of the first band-pass filter 10 (color signal band) and notch filter 11 (inputs 1 and 2 of EP 9). In this case, the chrominance signal is supplied to the first output of the ЭП 9, and the luminance signal is transmitted to the second output of the ЭП 9, i.e. in this case, vertical clarity is preserved in the corresponding image areas.

In the absence of all types of changes, the control signal connects the outputs of the electronic transformer 9 to the outputs of the first adder 14 and the second subtractor 16 (inputs 4 and 3 of the electronic transformer 9) through the third 13 and second 15 delay elements, respectively. At the same time, mutual noise immunity of luminance and color signals (absence of crosstalk) and preservation of image clarity are guaranteed.

The first 12, third 13 and second 15 delay elements are used to coordinate in time the working signals and control signals of the device.

Claims (1)

Claim A device for separating luminance and color signals, comprising a delay unit per line, a first subtractor, a first bandpass filter, a first low-pass filter, a notch filter, and a first adder and a second subtractor, the first inputs of which are connected and are the input of the device for separating luminance and color signals, characterized in that, in order to increase the mutual noise immunity of the luminance and color signals, a second adder is connected in series, the first input of which is connected to the output of the first subtractor, and an amplitude detector, a second low-pass filter, an amplitude limiter, a threshold element and an electronic switch, the first and second information inputs of which are connected to the outputs of the band-pass and notch filters, respectively, and the first and second outputs are respectively the first and second output of the device for separating luminance and color signals , the first delay element, the input of which is connected to the input of the first adder, and the output is connected to the inputs of the notch filter and the bandpass filter, a delay unit, the input of which connected to the input of the first delay element, and the output is connected to the second inputs of the first adder and the second subtractor, a second bandpass filter, the output of which is connected to the second input of the second adder, the second delay element, the input of which is connected to the output of the second subtractor and the input of the second bandpass filter and the output is connected to the third information input of the electronic switch, as well as the third delay element, the input of which is connected to the output of the first adder, and the output is connected to the fourth information input of the electronic a switch, the input of the first low-pass filter connected to the input of the first adder, and the output to the input of the delay unit per line and to the first input of the first subtractor, the second input of which is connected to the output of the delay unit to the line.