JPS6221393A - Chrominance signal correcting device for color video signal - Google Patents

Abstract

PURPOSE:To obtain a picture having the excellent brilliance of color even when the band of a color difference signal is limited by carrying out an operation between the color difference signal and a luminance signal and forming a correcting color difference signal of high frequency. CONSTITUTION:A luminance signal Y passes through the first filter 5, and is inputted to the first arithmetic circuit 7 after its low frequency component is taken out. The first arithmetic circuit 7, from three color difference signals R-Y, G-Y, B-Y and the luminance signal Y, outputs converting primary color signals Ra, Ga, Ba which are operated with the high frequency component of Y passing through the second filter 6 by the second arithmetic circuit 8. Then, in the third arithmetic circuit 9, a subtraction is performed, obtained correcting color difference signals of high frequency Rc, Gc, Bc are added to the original color difference signals R-Y, G-Y, B-Y by an adding circuit 10 to obtain corrected color difference signals Rd, Gd, Bd. Bands of the corrected color difference signals are respectively spread to higher sides than the original color difference signals R-Y, G-Y, B-Y. Thereby, when the reproduction is performed by using these corrected color difference signals Rd, Gd, Bd, the brilliance of the color is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for correcting high-frequency components of color signals included in color image signals.

[Conventional technology]

FIG. 3 shows a conventional color signal reproducing circuit, and (7) is a matrix circuit. (to) to (to) are adders that add the luminance signal Yt-to the output of the matrix circuit and extract the primary color output.

Next, the operation will be explained. The matrix circuit (7) generates two color difference signals I, Q to R-Y, G-Y, B-Y.
8 color difference signals are generated and added to the luminance signal Y through the adder ports to obtain the primary color signal holes, G and B, at the output terminal μQ-(g).

[Problem that the invention seeks to solve]

In conventional color video devices, due to various circumstances, the color difference is usually 0! Since the bandwidth of Goban-Y, G-Y, and B-Y is limited to about 5QOK7, if you directly reproduce this, the colors will be distorted.

This invention was made to solve the above problems, and even when the band of color difference signals is limited,
An object of the present invention is to obtain a color signal correction device capable of obtaining an image with good color saturation.

[Failure to solve the problem]

The color signal correction device according to the present invention performs calculations between a color difference signal and a luminance signal to create a color difference signal for high-frequency correction, and adds this signal to the original color difference signal to produce a high-frequency component. This is to obtain a color difference signal that has been corrected, that is, a color difference signal with a seemingly expanded band.

[Effect]

According to this invention, the band of the corrected color difference signal is wider than the band of the original color difference signal, for example, from 0 to 500.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is the input terminal for the luminance signal Y, (2)
, (3), (4) are color difference signal holes-Y, G-Y
, B-Y are input terminals. In addition, ordinary, G, and B are 3Jj
A color signal is shown.

(5) is a first filter that extracts low-frequency components, and (6) is a second filter that is a bandpass filter that extracts predetermined high-frequency components. The output of the first filter (5) and the color difference signal holes -Y, G-Y, B-Y are input to the first arithmetic circuit (7), and the output of the second filter (6) and the first The output of the arithmetic circuit (7) is sent to the second arithmetic circuit (8).
Furthermore, the output of the second filter (6) and the output of the second calculation circuit (8) are input to the third calculation circuit (9).
). Further, the output of the third arithmetic circuit (9) and the color difference signals R-Y, G-Y, B-Y are added with the addition circuit turned off. This added signal is sent to an adder (6
) ~ (1G is added to the luminance signal Y, output terminal Q←
1 is output.

In the above configuration, the luminance signal Y passes through the first filter (5), and after its low frequency components are extracted, it is limited to the same band as the color difference signal holes -Y, G-Y, and B-Y. After that, it is input to the first arithmetic circuit (7). On the other hand, color difference signal holes -Y, G-Y, B-Y are input terminals (2)
, (a) + (4) are directly input to the first arithmetic circuit (7). The first arithmetic circuit (7) generates three new converted primary color signals Ra, Ga + Ba from the three color difference multipliers -Y, G-Y, B-Y and the luminance signal Y.
Output. Here, KGB average == -, Qa knee, Ba = -Y
It is YY.

The above converted primary color signal fRa v Ga, Bat'i second
The signal is input to the arithmetic circuit (8) and is calculated with the high-frequency component of Y that has passed through the second filter (6). Here, if the high frequency component of Y is YH, then the second arithmetic circuit (8) outputs a primary color signal for correction. Next, the third arithmetic circuit (9)
Then subtraction is performed, Rc=R1)-YHI Gc=Gb-Ya J Bc=
Bb-Yn are output respectively. This Rc r Gc
+ B (is the high-frequency correction color difference signal υ, and the adder circuit Q
Original color difference signal hole-Y, G-Y, B-Y
The corrected color difference signals Rd, Gd,
Get Bd.

Here, . As is clear from this, the bands of the corrected color difference signals Rd, Gd, and Bd extend higher than those of the original color difference signals R-Y, G-Y, and BY, respectively. Therefore, if reproduction is performed using these corrected color difference signals Rd, Gd, and Bd, the vividness of colors will be improved.

Note that, as shown in FIG. 2, the correction color difference signal RC*G
(rB() is added to the original color difference signals R-Y, G-Y, B-Y after addition 944: j, α(, (a),
A similar effect can be obtained.

Further, in the above embodiment, the second filter (6) is a bandpass filter, but it may be replaced with an appropriate filter depending on the nature of the intended correction. Furthermore, as the color difference signals, 几-Y and G-Y are used in the above embodiment.

Although B-Y is used, other repeating axes may also be used.

〔Effect of the invention〕

As described above, according to the present invention, since reproduction is possible using corrected color difference signals with a wide band, there is an advantage that an image with good definition can be obtained even if the band of the actual color difference signal is limited. .

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a color signal correction device for color video signals according to one embodiment of the present invention, FIG. 2 is a system diagram showing main parts of another embodiment, and FIG. 3 is a system diagram showing a conventional example. It is. (5), (6)...filter, (7)-(9)・
...Arithmetic (b) path, GO...addition circuit, R, G,
B-=color signal, Rar Gar Ba-=converted primary color signal, Rb, Gb, Bb...primary color signal for correction, R
Cr Gc l B (...corrected color difference signal, Y/
...Brightness signal. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A first filter that extracts the low frequency component of the luminance signal, a first calculation circuit that calculates the extracted low frequency component and color difference signal and outputs a converted primary color signal, and a first calculation circuit that extracts the high frequency component of the luminance signal. a second filter, and a second filter that calculates the extracted high frequency component and the converted primary color signal and outputs a correction primary color signal.
a third arithmetic circuit that calculates the high frequency component of the extracted luminance signal and the primary color signal for correction and outputs a high frequency color difference signal for correction; 1. A color signal correction device for a color video signal, comprising: an addition circuit that adds the color difference signal to the color difference signal and outputs a color difference signal with high frequency components corrected.