JPH01202092A - Brightness signal/chrominance signal separating device and magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a luminance signal/chrominance signal separation (hereinafter abbreviated as Y/C separation) device used in video tape recorders and the like.

Conventional technology In recent years, consumer video tape recorders (VTRs) have
Demand for higher image quality is increasing, and Y resolution is high (Y/
S-V HS method VTR-jED with C separate input and output
With the advent of Beta type VTRs, the importance of Y/C separation equipment that separates composite and solitary signals from Y/C has increased.

A comb filter is used for Y/C separation, but dot interference and cross colors may become more noticeable.
By looking at the correlation between lines, it is necessary to judge whether the signal should be processed through a comb filter or a simple bandpass filter.

Hereinafter, an example of the above-mentioned conventional Y/C separation device will be described with reference to the drawings. Figure 2 shows the conventional Y/C
This shows a separation device. In FIG. 2, 12 is a band pass filter that passes the color signal band, 13 is a delay circuit, and the amount of delay is 1H in the case of an NTSG signal.
In the case of a PAL signal, it is 2H. 14 is an arithmetic circuit, which is an addition circuit, 16 is a selection circuit, and 16 is a subtraction circuit. 17 is a multiplication circuit that multiplies the input by 〃. 18 is a switching circuit, 19
is a subtraction circuit.

The operation of the Y/C separation device configured as described above will be explained below using FIG. 2.

The color signal band components of the video signal input are separated by BPFl 2, and this separated output signal is converted into 1 by the delay circuit 13.
Delayed by H (or 2H).

The signal output from BPFl2 and the signal that has passed through the delay circuit 13 are added in an adder circuit 14, and the signal output from BPFl2 is added in a subtracter circuit 16 to the signal that has passed through the delay circuit 13.
The signal that has passed through 3 is subtracted. And multiplication circuit 1
7, the output value of the subtraction circuit 16 is subtracted. The output of this multiplication circuit 17 becomes the comb filter output of the color signal. The output of the adder circuit 14 is input to the selection circuit 16,
If the absolute value of the value is smaller than a certain value, it is determined that there is a correlation between the signal output from the BPFL 2 and the signal output from the delay circuit 13, and the output of the switching circuit 18 is determined by the multiplication circuit 1.
The result is 7, and this becomes the color signal output. Further, if the absolute value of the value input to the selection circuit 15 is larger than a certain value,
It is determined that there is no correlation between the signal output from the BPFL 2 and the signal output from the delay circuit 13, and the switching circuit 18
The output of is the signal output from BPFl 2,
This becomes a new color signal output. A subtraction circuit 19 subtracts the color signal from the video signal to produce a luminance signal.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, when the reproduced image has vertical stripes, the adder circuit 14 component contains the high-frequency component of the luminance signal, and it is determined that there is no correlation between them. B.P.
There was a problem in that it resulted in a form in which Fl 2 appeared, resulting in cross color. Furthermore, if the delay amount of the delay circuit is doubled, a variety of correlation information can be obtained, but a problem arises in that the cost of configuring the delay circuit and its peripheral circuits increases accordingly. A similar problem occurs even when Y/C separation is digitally processed.

In view of the above problems, the present invention provides a luminance signal/chrominance signal separation device that can perform more accurate Y/C separation without increasing the memory.

Means for Solving the Problems In order to solve the above problems, the luminance signal/chrominance signal separation device of the present invention includes an analog/digital converter that converts an input analog video signal into a digital video signal, and an analog/digital converter that converts an input analog video signal into a digital video signal. a first delay circuit that delays a video signal converted to a digital signal by n horizontal periods (n is a positive integer); and a first bandpass filter that receives the digital video signal and passes its color signal band component. , a second bandpass filter that manually inputs the digital video signal output from the first delay circuit and passes its color signal band component; and an output signal of the first bandpass filter and the second bandpass filter. a first arithmetic circuit that calculates the sum with the output signal of the filter; a conversion circuit that converts the sum output of the first arithmetic circuit into a certain type of correlation value according to its output level; and the conversion circuit. a second delay circuit that delays the correlation value output from the second delay circuit by m (m is a positive integer) horizontal period; and a second delay circuit that delays the correlation value output from the second delay circuit by a horizontal period (lcl is a positive integer). a third delay circuit that subtracts the output signal of the first band-pass filter from the output signal of the second band-pass filter; and a second arithmetic circuit that subtracts the output signal of the first band-pass filter from the output signal of the second band-pass filter; Third
an arithmetic circuit; a switching circuit that outputs either the output signal of the third arithmetic circuit or the output signal of the second bandpass filter according to a selection signal; and the output signal of the second delay circuit. a selection circuit that receives the correlation value output from the third delay circuit and the correlation value output from the third delay circuit and outputs a selection signal to the switching circuit; and an output signal of the switching circuit based on the output video signal of the first delay circuit. A fourth arithmetic circuit for subtracting.

Operation With the above-described configuration, a video signal is first converted into a digital signal by an analog/digital (MU10) converter,
This video signal converted into a digital signal is input to a first delay circuit and a first bandpass filter. 1st
The signal output from the delay circuit is input to the second bandpass filter. The signal output from the first band-pass filter and the signal output from the second band-pass filter are input to a first arithmetic circuit, and the sum thereof is calculated. The output of this first arithmetic circuit is input to a conversion circuit that converts it into a certain type of correlation value according to its output level. Also, the output from the conversion circuit is
It is delayed by a second delay circuit, and the output of this second delay circuit is further delayed by a third delay circuit.

The output of the conversion circuit and the second. Based on the output of the third delay circuit, it is determined whether the output of the third arithmetic circuit is to be used as a color signal output or the output of the second bandpass filter is to be used as a color signal output. The luminance signal is obtained by subtracting the color signal output from the video signal output from the first delay circuit.

Embodiment Hereinafter, a luminance signal/chrominance signal separation device for a PAL VTR, which is an embodiment of the present invention, will be described with reference to the drawings. FIG. 1 is a block diagram of a luminance signal/chrominance signal separation device for a PAL VTR according to an embodiment of the present invention. In Figure 1, 1 digit analog/digital (Mu/D)
Converter, 2 is a first delay circuit (delay time is 2H), 3 is a first band pass filter (hereinafter abbreviated as BPF), 4 is a second BPF, 5 is an adder, 6 is a conversion circuit, 7 are the second delay circuit (delay time is 1H), the 8-digit third delay circuit (delay time is 1H), 9 is the subtracter, 1o is the multiplier, 11 is the selection circuit, 2o is the switching circuit, and 21 is the It is a subtractor.

Luminance signal 7 of PAL VTR configured as above
The operation of the color signal separation device will be described below with reference to FIG.

An input analog video signal is converted into a digital signal by a multi-digital converter 1. The video signal converted into a digital signal is sent to the first delay circuit 2 and the first BPF 3.
The video signal input to the second BPF 4 and delayed by 2H in the first delay circuit 2 is input to the second BPF 4 . 2nd BP
From the output of F4, the output of the first BPF 3 is subtracted in a subtracter 9, and this subtracter 9 output is multiplied by a multiplier 1o to obtain a comb filter output. Further, the output of the second BPF 4 and the output of the first BPF 3 are added by °C in an adder, and the output of the adder 6 is converted into binary correlation information by a conversion circuit 6. When the magnitude of the adder output is smaller than a certain level, an H level output indicating the presence of correlation is output, and when it is greater than a certain level, an L level output indicating no correlation is output. The output of this conversion (b) path 6 is input to a second delay circuit 7, and the signal delayed by 1H in this delay circuit 7 is further input to a third delay circuit 8.

This delay circuit 8 delays the signal by 1H. Conversion circuit 6
, the output of the second delay circuit 7, and the output of the third delay circuit 8 are all input to the selection circuit 11, where they are either made into the comb filter output component as the color signal output, or are outputted from the BPF.
Decide whether to use it as an output component. In other words, when the output of the conversion circuit 6 is correlated (H level), or when the output of the conversion circuit 6 is uncorrelated (L level), the output of the second delay circuit 7 is uncorrelated (L level), and the third When the output of the delay circuit 8 is uncorrelated (L level), the output of the multiplier 1o, that is, the comb filter output is used as the color signal output. Further, when the output of the conversion circuit 6 is uncorrelated (L level) and the output of the third delay circuit 8 is correlated (H level), or the output of the conversion circuit 6 is uncorrelated (L level) and the second delay circuit 7
When the output of is correlated (H level), the second BPF4
Let the output be the color signal output. The luminance signal is obtained by subtracting the color signal output from the output of the first delay circuit 2 using a subtracter 21.

As described above, according to this embodiment, when performing Y/C separation on a video signal that has been subjected to M/D conversion and digitized, correlation information between the original signal and the delayed signal is stored, By using this information later, the presence or absence of correlation can be detected more accurately, and the number of memory devices will hardly increase.

Effects of the Invention As described above, according to the present invention, since only the correlation information between the original signal and the delayed signal is extracted and delayed, the amount of memory for delaying can be reduced. , it is possible to obtain excellent effects such as realizing a luminance signal/chrominance signal separation device with improved luminance signal/chrominance signal separation accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a luminance signal/chrominance signal separation device of a PAL system VTR according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional luminance signal/chrominance signal separation device. 1...A/D converter, 2...1st
delay circuit, 3...first BPF, 4...
...Second BPF, 6... Adder, 6...
・Conversion circuit, 7・Old...Second delay circuit, 8...
・Third delay circuit, 9...Subtractor, 1°...
... Multiplier, 11... Selection circuit, 2o...
...Switching circuit, 21...Subtractor. Name of agent: Patent attorney Toshio Nakao and 1 other person11
1-′...,”1-11

Claims (3)

[Claims] (1) An analog/digital converter that converts an input analog video signal into a digital video signal, and an analog/digital converter that delays the video signal converted to a digital signal by the analog/digital converter by a horizontal period of n (n is a positive integer). 1 delay circuit; a first bandpass filter that receives the digital video signal and passes its color signal band components;
a second band-pass filter that receives the digital video signal output from the delay circuit and passes its color signal band component; an output signal of the first band-pass filter; and an output signal of the second band-pass filter. a first arithmetic circuit that calculates the sum of the first arithmetic circuit; a conversion circuit that converts the sum output of the first arithmetic circuit into a certain type of correlation value according to the output level; a second delay circuit that delays the correlation value output by m (m is a positive integer) horizontal period, and a correlation value output from the second delay circuit that delays l
(l is a positive integer); a third delay circuit that delays the horizontal period; a second arithmetic circuit that subtracts the output signal of the first band-pass filter from the output signal of the second band-pass filter; The third multiplier that multiplies the output of the second arithmetic circuit by 1/2
an arithmetic circuit; a switching circuit that outputs either the output signal of the third arithmetic circuit or the output signal of the second bandpass filter according to a selection signal; and the output signal of the second delay circuit. a selection circuit that receives the correlation value output from the third delay circuit and the correlation value output from the third delay circuit and outputs a selection signal to the switching circuit; and an output signal of the switching circuit based on the output video signal of the first delay circuit. and a fourth arithmetic circuit that subtracts the switching circuit, and obtains a color signal as an output of the switching circuit and a luminance signal as an output of the fourth arithmetic circuit. (2) The delay amount of the first delay circuit is 2 horizontal periods, the delay amount of the second and third delay circuits is 1 horizontal period, and whether the correlation value output from the conversion circuit is above a certain level. when the output of the conversion circuit is a signal indicating the presence of correlation and the output of the conversion circuit is a signal indicating the presence of correlation, or the output of the conversion circuit is a signal indicating no correlation and the output of the second delay circuit. is a signal indicating no correlation and the output of the third delay circuit is a signal indicating no correlation, the selection circuit supplies the switching circuit with a selection signal for selectively outputting the output signal of the third arithmetic circuit, and When the output of the conversion circuit is a signal indicating no correlation and the output of the third delay circuit is a signal indicating presence of correlation, or the output of the conversion circuit is a signal indicating no correlation and the output of the second delay circuit 2. The luminance signal/color according to claim 1, wherein the selection circuit supplies a selection signal for selectively outputting the output signal of the second band-pass filter when the selection circuit is a signal indicating that there is a correlation. Signal separation device. (3) A magnetic recording and reproducing device comprising the luminance signal/chrominance signal separation device according to claim 1 or 2.