KR19990086889A - Color correction circuit - Google Patents

Abstract

In particular, the present invention relates to a color correction circuit using white detection, and more particularly, a data integrating unit for integrating the cr and cb signals only when an integral enable signal is input after generating the chrominance signals cr and cb by receiving ccd data of a camera. A control unit for detecting a red (r) gain and a blue (b) gain by receiving an integration result of the data integration unit and calculating white balance; and ccd data input using r gain and b gain data detected by the control unit. A gain adjustment and signal generator for adjusting the color gain of the signal and converting it to a y, ry, and by signal, and estimating white from the y, ry, by signal output from the gain adjustment and signal generator, and integrating according to the estimation result. And a white detector for outputting an enable signal to the data integrator, where y is greater than or equal to the threshold and the absolute value of ry, by is less than or equal to the threshold. By integrating and controlling the integration, the white balance can be performed by detecting only white regardless of the screen configuration, so that white balance can be realized under any conditions.

Description

Color correction circuit

The present invention relates to the processing of color image signals, and more particularly, to a color correction circuit using white detection.

In general, the color of white varies depending on the color temperature of the light. The human eye recognizes it as white regardless of the light by adapting to it and removing the color change. On the contrary, the camera shows the image as it is and displays it with the color change. The white screen is displayed in a different color. The elimination of this phenomenon is a conventional white balance adjustment method. In other words, integrating cr and cb data in one screen unit, respectively, to satisfy the conditions of | sum (cr)-sum (cb) | <a (= a is white balance estimated minimum margin). b) to adjust the gain.

FIG. 1 is a block diagram illustrating a conventional color correction circuit. The cr / cb generator 11 receives a charge coupled device (ccd) data of a camera and generates cr / cb, which is a color difference signal, and the cr. Data integrating unit 12 for integrating the / cb signal, the microcomputer 13 for detecting the r gain and the b gain by receiving the output of the integrating unit 12 and calculating white balance, and the r detected by the microcom 13 A color gain adjusting unit 14 for adjusting the color gain of the ccd data input using the gain and b gain data, a signal generating unit 15 for generating y, ry, and by signals from the ccd data whose color gain is adjusted, and The video signal generator 16 generates a standard video signal from the y, ry, and by signals.

In FIG. 1 configured as described above, the cr / cb generating unit 11 generates the color difference signals cr and cb from the input ccd data and outputs them to the data integrating unit 12, and the data integrating unit 12 is cr in one screen unit. / cb data are integrated and output to the microcomputer 13.

The microcomputer 13 adjusts the red (r) gain and the blue (b) gain during the next screen so that | sum (cr)-sum (cb) | <a (= a is white balance estimated minimum margin) to be satisfied. The signal is input to the color gain adjusting unit 14 as a signal in one screen unit.

The color gain adjusting unit 14 adjusts the color gain of the ccd data input by the r gain and the b gain output from the microcomputer 13 and outputs the color gain to the signal generator 15, and the signal generator 15 The r, g, and b data of which color gain is adjusted are converted into y, ry, and by signals and output to the video signal generator 16. The video signal generator 16 converts the y, r-y, and b-y signals into standard video signals and outputs the standard video signals.

However, the conventional method described above is based on the assumption that the integral value of one screen is almost equal to cr and cb. Actually, only white is controlled. Therefore, if one screen has a monochromatic advantage, the white balance operation is performed. It has a disadvantage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a color correction circuit that enables white balance operation on any screen by detecting and integrating only white to adjust red gain and blue gain. have.

1 is a block diagram of a conventional color correction circuit

2 is a block diagram of a color correction circuit according to the present invention;

3 is a detailed block diagram of the white detector of FIG. 2;

Explanation of symbols for main parts of the drawings

21: cr / cb generation unit 22: data integration unit

23: micom 24: color gain adjustment unit

25: signal generator 26: white detector

27 video signal generator 31 to 33 comparator

34: logic section

The color correction circuit according to the present invention for achieving the above object, after receiving the ccd data of the camera to generate the color difference signal cr, cb and then integrate the cr, cb signal only when the integral enable signal is input A control unit for detecting a red (r) gain and a blue (b) gain by receiving a data integrating unit, an integration result of the data integrating unit, and performing white balance calculation, and using the r gain and b gain data detected by the control unit. White color by using the gain adjusting and signal generating unit for adjusting the color gain of the input ccd data and converting it into a y, ry, and by signal, and the y, ry and by signals output from the gain adjusting and signal generating unit. And a white detector for estimating and outputting an integral enable signal to the data integrator according to the estimation result.

The white detector may estimate white and output an integral enable signal only when a y signal is larger than white threshold data provided by the controller and an absolute value of r-y and b-y signals is smaller than the white threshold data.

The controller may adjust the white estimation region by varying the white threshold data.

This color correction circuit can realize white balance under any conditions.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram of a color correction circuit according to the present invention, which receives a charge coupled device (ccd) data of a camera and generates a cr / cb generator 21 for generating a cr / cb, which is a color difference signal. The data integrating unit 22 for integrating the cr / cb signal only when the enable signal is input, and the microcomputer 23 for detecting r gain and b gain by calculating the white balance by receiving the output of the integrating unit 22. And a color gain adjusting unit 24 for adjusting the color gain of the ccd data input using r gain and b gain data detected by the microcomputer 23, and y, ry, and by signals from the ccd data where the color gain is adjusted. A white detector 26 which detects white from the y, ry, and by signals and outputs an integral enable signal to the data integrator 22 according to a detection result, and y, From ry, by signal to standard video signal G., Which consists of a video signal generator 27.

In the present invention configured as described above, the cr / cb generator 21 generates the color difference signals cr and cb from the input ccd data and outputs them to the data integrator 22, and the data integrator 22 integrates the enable signal. Only when is inputted, the cr / cb data is integrated and the cr / cb data is integrated in one screen unit to be output to the microcomputer 23.

That is, the data integrating unit 22 integrates only a portion estimated to be white on one screen and outputs it to the microcomputer 23, and the microcom 23 receives red (r) gain and blue (b) for the next screen. The gain is adjusted so that | sum (cr)-sum (cb) | <a (= a is white balance estimated minimum margin) to be output to the color gain adjusting unit 24 as a signal in one screen unit. The color gain adjusting unit 24 adjusts the color gain of the ccd data input using the r gain and the b gain output from the microcomputer 23, and then outputs the color gain to the signal generator 25 and outputs the signal generator 25. 25 converts r, g, b data of which color gain is adjusted into y, ry, and by signals and outputs them to the white detector 26 and the video signal generator 27. The video signal generator 27 converts the y, r-y, and b-y signals into standard video signals and outputs the standard video signals.

Meanwhile, as illustrated in FIG. 3, the white detector 26 compares whether the y signal is greater than the white threshold data and the first comparator 31 compares whether the | ry | signal is smaller than the white threshold data. The comparator 32, the third comparator 33 for comparing whether the | by | signal is smaller than the white threshold data, and the y signal is greater than the white threshold data, and the | ry |, | by | signals are smaller than the white threshold data. And a logic unit 34 that estimates white and outputs an integral enable signal to the data integrating unit 22.

In this case, the white threshold data is provided by the microcomputer 23, and the microcomputer 23 may adjust the white estimation region by varying the white threshold data.

That is, the first comparator 31 determines that the y signal is greater than the white threshold data, the second comparator 32 determines that the | ry | signal is smaller than the white threshold data, and the third comparator 33 determines | by | Only when it is determined that the signal is smaller than the white threshold data, the logic unit 34 estimates white and outputs an integral enable signal to the data integrator 22, and the integrator 22 inputs an integral enable signal. Only when the cr / cb signal is integrated.

As described above, according to the color correction circuit according to the present invention, y is estimated to be white only when the absolute value of ry and by is greater than a certain threshold value, and all of the absolute values of ry and by are related to the screen configuration. The white balance can be performed by detecting only white without the white balance. In addition, the white estimation region can be adjusted by varying the threshold.

Claims (7)

A data integrator for integrating the cr and cb signals only when the integral enable signal is input after generating the cr / cb signals that receive the ccd data of the camera; A control unit which receives the integration result of the data integration unit and calculates a white balance to detect red (r) gain and blue (b) gain; A gain adjusting and signal generating unit for adjusting the color gain of the input ccd data using the r gain and b gain data detected by the control unit and converting the color gain into y, r-y, and b-y signals; And a white detector for estimating white using the y, ry, and by signals output from the gain adjusting and signal generator and outputting an integral enable signal to the data integrator according to the estimation result. Circuit. The method of claim 1, wherein the data integration unit A color correction circuit characterized by integrating only portions estimated to be white on one screen. The method of claim 1, wherein the control unit The signal in one screen unit after adjusting the red (r) and blue (b) gains for the next screen to satisfy | sum (cr)-sum (cb) | <a (= a is the white balance estimated minimum margin). Color correction circuit characterized in that the output. The method of claim 1, wherein the white detector a first comparator comparing whether the y signal is greater than the white threshold data; a second comparator comparing whether the absolute value of the r-y signal is smaller than the white threshold data; a third comparator comparing whether the absolute value of the b-y signal is smaller than the white threshold data; And a logic unit for estimating white by combining the comparison results of the first to third comparators, and outputting an integral enable signal only when the white is estimated to be white. The method of claim 4, wherein the logic unit and estimating white only when the y signal is larger than the white threshold data and the absolute values of the r-y and b-y signals are smaller than the white threshold data. The method of claim 4, wherein the white threshold data is And a color correction circuit provided by the controller. The method of claim 6, wherein the control unit And adjusting a white estimation region by varying the white threshold data.