JPS60200694A - Correction circuit of color difference signal - Google Patents

Abstract

PURPOSE:To obtain a correct white valance on the entire picture by providing a correction table covering the entire picture with respect to a color difference signal, and adding data in the correcting table to actual data in synchronizing with a picture input. CONSTITUTION:First, a complex video signal from a color television camera 1 is separated into a (B-Y) signal 11a and a (R-Y) signal 11b at a color difference signal separator circuit 2. Then these color difference signals are digitized by A/D convertors 3a and 3b and inputted to adders 7a and 7b. On the other hand, an output signal from the color television camera 1 is inputted to a synchronism separator circuit 4 and controls correction memories 6a and 6b, a hue memory 9a and a picture memory address of a saturation memory 9b through an address generator circuit 5. Outputs from the correction memories 6a and 6b are added to the color difference signal from the color television camera 1 in the adders 7 and 7b, whereby a color difference signal completely white-balanced can be obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a circuit for correcting color difference signals, and particularly to a color difference signal correction circuit suitable for obtaining correct white balance over the entire screen. .

[Background of the invention]

Traditionally, video has not been converted from a color television camera. In other words, even when capturing a white screen,
The first vector scope is an example of color difference signals on a white screen.
As shown in the figure, the color difference signal (B-Y), <R-Y)
The waveform on the vectorscope had a wide spread. This is because it is difficult to adjust the white balance on the camera side over the entire television screen.
It's no good that I matched it to the average. When attempting to perform highly accurate chromaticity determination using a color TV camera, it is necessary to maintain correct white balance across the entire screen, but conventional circuits do not.

With this method, the accuracy of the color difference signal was poor, making it difficult to measure chromaticity with high precision.

[Purpose of the invention]

In view of the above circumstances, an object of the present invention is to provide a redundant color difference signal correction circuit that enables highly accurate chromaticity measurement.

[Summary of the invention]

The color difference signal correction circuit according to the present invention includes a color TV difference signal separation circuit, and A for digitizing the color difference signal.
It consists of a D converter, a correction memory in which a color difference signal correction table for the color TV camera is stored, and an addition circuit that adds the output of the D converter and the above-mentioned gage digitized color difference signal to obtain a corrected color difference signal. This is what I did.

In short, a correction table covering the entire screen is provided for the color difference signals (B-Y) and (R-Y), and data in this correction table is converted to the actual data in synchronization with image input. By adding these values, the correct white balance can be obtained over the entire screen.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of an embodiment of the color difference signal correction circuit according to the present invention.

Here, 1 is a color TV camera, 2 is a color difference signal separation circuit, 3a, 3b are A/D converters, 4 is a synchronous separation circuit, 5 is an address generation circuit, 5a, 6b are color difference signal correction tables, 7a, 7b 8 is an addition circuit, 8 is an arithmetic circuit, 9a is a hue memory, 9b is a saturation memory, and 10 is a computer.

First, a composite video signal from the color TV camera 1 is separated into a (B-Y) signal 11a and a (B-Y) signal 11b by the color difference signal separation circuit 2. Next, convert these color difference signals into A
/D converters 3a, 3b digitize and adder circuit 7.
Input in a and 7b.

On the other hand, the output signal from the color TV camera 1 is input to the synchronization separation circuit 4, and is passed through the address generation circuit 5 to the correction memos IJ6a, 6b, hue memory 9a, and saturation memory 9.
1] controls the image memory address. Correction memory 6a
, 6b, a color difference signal correction table, which is measured by capturing an image of a white screen using a color TV camera to be used, is written in advance. This correction table is one-to-one with each pixel.
It is stored in the correction memo IJ6a, 6b in a corresponding form.

The outputs from correction memo 'J6a and 6b are sent to adders 7a and 7.
By adding the color difference signal from the color TV camera 1 at step b, a color difference signal with perfect white balance is obtained. This corrected color difference signal is sent to the calculation circuit 8.
Through, hue θ.

Saturation r is divided, hue memo')" a + saturation memory 9
b. Hue and saturation are calculated using the following formula % formula % (
2) The contents of the memories 9a and 9b are read out from time to time by the computer 10, and are used to extract areas with a certain chromaticity, etc.
It can be effectively used for color pattern recognition.

〔Effect of the invention〕

According to the present invention, the white balance of a color TV camera can be perfectly maintained over all parts of the 11! can get.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a vector circuit for an example of a color difference signal of a white screen. DESCRIPTION OF SYMBOLS 1... Color TV camera, 2... Color difference signal separation circuit, 3a, 3b... A/D converter, 4... Synchronization separation circuit, 5... Address start circuit, 6a, 6b. ...Correction memory, 7a, 7L+...Addition circuit, 8...Arithmetic circuit, 9a...Hue memory, 9b...Saturation memory, 10
...Conview Kaya I Mouth R-E>Z-kuni

Claims (1)

[Claims] 1. A color difference signal separation circuit that separates a color difference signal from a video signal from a color TV camera, and an A/D converter that digitizes the color difference signal. A color difference signal correction circuit comprising a correction memory storing a color difference signal correction table for the color TV camera, and an addition circuit that adds the output of the memory and the digital color difference signal to obtain a corrected color difference signal. .