JPH02309888A - Video signal correcting device - Google Patents

Abstract

PURPOSE:To improve the reproducibility of a video signal by converting an inputted analog luminance signal and an inputted color difference signal into the digital signals, outputting the correction data based on those digital signals, and correcting those analog luminance signal and color difference signal based on the analog correction signal obtained by converting the correction data. CONSTITUTION:The inputted analog luminance signal Y and color difference signals R-Y and B-Y are converted into the digital signals by the A/D converters 1A-1C. Based on the levels of these digital signals, the correction data is outputted from a correction data storage means 6. This outputted correction data is converted into the analog correction signals by the D/A converters 3A-3C, and the inputted signals Y, R-Y and B-Y are corrected by the correction signal. In this case, the means 6 is turned into a rewritable one and the contents of the means 6 are rewritten. Thus the signal correction is carried out in proper accordance with the characteristics of the inputted luminance and color difference signals. As a result, a video signal which excels in the color reproducibility is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a video signal correction device for correcting a video signal.

[Conventional technology] Current color video cameras are smaller, lighter, and consume less energy.
Electrification is progressing, and as a result, it is becoming more widespread. These current color video cameras are
For example, CCD (Charge Coupled Device
It is configured to obtain color video signals using an image sensor such as CE).

[Problem to be solved by the invention]

However, depending on the imaging method of the color video camera mentioned above, when obtaining a color video signal, the red signal, green signal, and blue signal may be mixed at a mixing ratio different from the normal ratio. The color video signal obtained in this case exhibits color reproducibility different from that of the original color video.

An object of the present invention is to provide a video signal correction device that can solve the above problems and improve the reproducibility of video signals.

[Means to solve the problem]

The video signal correction device of the present invention receives an analog luminance signal and a color difference signal, and includes an analog-to-digital conversion means for converting the input analog luminance signal and color difference signal into digital signals, and an output signal from the analog-to-digital conversion means. a rewritable correction data storage means for outputting correction data based on a digital luminance signal and a color difference signal; a digital-to-analog conversion means for converting the correction data obtained from the correction data storage means into an analog correction signal; The apparatus includes a correction means for correcting the input analog luminance signal and color difference signal using the analog correction signal output from the digital-to-analog conversion means.

[For production]

According to the above configuration, the input analog luminance signal and color difference signal are converted into analog-to-digital signals, the correction data is output from the correction data storage means according to the level of the digital signal, and the output correction data is converted into an analog correction signal. When converting and correcting the input analog luminance signal and color difference signal using the correction signal, the correction data storage means is made rewritable, and by rewriting the contents, the input luminance signal and color difference signal By performing correction appropriately corresponding to the characteristics of the image, it is possible to obtain a video signal with excellent color reproducibility.

(Example) Hereinafter, the present invention will be explained using examples of the present invention.

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention.

In FIG. 1, IA, 1 [1, IC is a to/D converter, and 2 is a look-up table (hereinafter referred to as L, U, and T) composed of a rewritable memory.

3^, 3B, 3C are D/^ converters, 4^, 4B,
4G is an adder circuit. 5 is a microcomputer (hereinafter referred to as microcomputer), 6 is a read-only memory (hereinafter referred to as ROM), and 7 is a switch circuit.

In the above configuration, to input/D converter l, IB, I
C converts the analog luminance signal (Y) and two types of color difference signals (R-Y, B-Y) input from the input terminals 100A, 100B, and 100C into digital signals,
Enter L, U, 7.2. L, IJ, 7.2 output correction data for the level of the input signal. The output correction data is sent to the D/A converter 3^, 3B,
It is converted into an analog correction signal in 3G, and input terminal 100A%100 in adder circuits 4A, 4B, 4-C.
Correction is performed by adding it to the analog luminance signal and color difference signal input from B%100C, and output terminals 200A and 200B.

Output from 200C.

On the other hand, the microcomputer 5 first monitors the state of the switch circuit 7. This switch circuit 7 can be switched manually or automatically depending on the color temperature of the subject being photographed by the video camera equipped with this correction device. Then, the microcomputer 5 detects information on the color temperature of the subject set by the switch circuit 7, and reads out correction data corresponding to the detected color temperature information from the R'OM8. In ROM6,
Correction data for each color temperature of the subject is stored in advance, and as described above, the microcomputer 5 reads out the correction data and transfers it to L, U, and 7.2. From then on, the microcomputer 5 reads the correction data corresponding to the color temperature of the subject from the ROM 6 every time the state of the switch 7 changes, and reads out the correction data corresponding to the color temperature of the subject.
Perform the operation of writing to.

As described above, according to the configuration described above, correction processing is performed to always perform appropriate color reproduction by switching the switch manually or automatically according to changes in the color temperature of the subject being photographed with the color video camera. It's going to happen.

In this embodiment, the information switched by the switch circuit is not limited to color temperature information, but may also be subject brightness information. In addition, the contents of the data to be stored in the ROM are not data for directly writing to L, U, and T.
, U, and T, the data for automatically generating the correction data may be stored in the ROM by performing calculations by a microcomputer.

In this case, the capacity of the correction data can be reduced by automatically generating the correction data to be written in U and T by the microcomputer.

FIG. 2 is a diagram showing a schematic configuration of a second embodiment of the present invention.

In FIG. 2, parts having the same functions as those in FIG. 1 are given the same numbers.

In the second embodiment, the difference from the first embodiment is that the color temperature information given to the microcomputer 5 is not inputted by a switch circuit, but is automatically inputted from another circuit, such as the white balance circuit 8 of a color video camera. This is a well-known point.

The microcomputer 5 selects correction data from the ROM 6 based on the color temperature information input from the white balance circuit 8.
Read it and transfer it to Il, Ding, 2. Thereafter, the microcomputer 5 performs an operation of transferring correction data from the ROM 6 to the LIJ, T, and 2 each time the color temperature information supplied from the white balance circuit 8 changes.

FIG. 3 is a diagram showing a schematic configuration of a third embodiment of the present invention.

In FIG. 3, parts having the same functions as those in FIG. 1 are given the same numbers.

In FIG. 3, 9 is an electrically writable and erasable read-only memory (hereinafter referred to as EEP-ROM).

When adjusting the color video camera, characteristic information specific to the camera is written in the EEP-ROM 9.

In the above configuration, the microcomputer 5 first stores the EEP-ROM 9
By reading the characteristic information unique to the video camera, modifying the correction data read from ROM 6 based on the characteristic information, and transferring the correction data to U, T, and 2, it is possible to adjust the characteristics unique to the video camera. This makes it possible to perform the most appropriate correction.

(Effects of the Invention) As described above, the video signal correction device of the present invention always optimally corrects the video signal without being affected by the color temperature information of the subject or the characteristics unique to the camera, and reproduces the video signal. can improve sex.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention, FIG. 2 is a block diagram showing a schematic configuration of a second embodiment of the present invention, and FIG. 3 is a block diagram showing a schematic configuration of a second embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of an example. IA, 1B, IC...^/D converter, 2...
・Lookup table, 38, 3B, 3C...D/8 converter, 4A,
4B, 4C...addition circuit, 5...microcomputer, 6...read-only memory, 7...switch circuit, 8...white balance circuit, 9...electrically writable and erasable readout Dedicated memory.

Claims (1)

[Claims] 1) Analog-digital conversion means for inputting an analog luminance signal and color difference signal and converting the input analog luminance signal and color difference signal into digital signals; and an output from the analog-digital conversion means. a rewritable correction data storage means for outputting correction data based on a digital luminance signal and a color difference signal; a digital-to-analog conversion means for converting the correction data obtained from the correction data storage means into an analog correction signal; A video signal correction device comprising a correction means for correcting an input analog luminance signal and color difference signal using an analog correction signal output from a digital-to-analog conversion means.