JP2000069500A - Automatic discriminant circuit for luminance equation of color television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically discriminate a signal system by comparing a luminance signal generated by an assumed luminance equation with an original luminance signal and discriminating the signal system as that of the assumed luminance equation when two luminance signals coincide. SOLUTION: A green signal G is outputted by inputting a color difference signal G-Y of green and the luminance signal Y into an adding circuit 3. The luminance signal Y is outputted by inputting a red signal R, a blue signal B and the green signal G into a luminance signal Y matrix circuit 6. The luminance signal outputted from the matrix circuit 6 and the originally inputted luminance signal are inputted into a comparator circuit 8 and its output is inputted into a microcomputer 9. When the luminance equation set by a G-Y matrix switching circuit 5 and a luminance equation switching circuit 7 coincides with the luminance equation of the received signals, the output of the comparator circuit 8 becomes zero. When the luminance equations are different, the same operation is repeated by switching the coefficients of the G-Y matrix switching circuit 5 and the luminance equation switching circuit 7 to the coefficient of another luminance equation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for automatically judging a luminance equation of a color television receiver.

[0002]

2. Description of the Related Art Conventionally, when a signal is received by a color television receiver using a signal system having a different luminance equation,
The correct image reception was realized by manually switching the matrix circuit according to the used luminance equation.

[0003]

In a color television receiver, it is inconvenient to manually switch the matrix. In addition, when the signal system is changed during the broadcast, manual switching is performed every time. Is complicated.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, a luminance equation automatic discrimination circuit of a color television receiver according to the present invention assumes a luminance equation of any one of the methods and converts a green color difference signal. Generated from the red and blue color difference signals, and from the red and blue and green signals generated by adding the luminance signal and the red and blue and green color difference signals, a luminance signal generated from the assumed luminance equation , And the original luminance signal. When the two luminance signals coincide with each other, the signal system of the assumed luminance equation is automatically determined.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is based on the assumption that in a color television receiver, a luminance equation of one of the systems is automatically determined as a method of automatically determining a luminance equation of an input signal system. Then, a green color difference signal is generated from the red and blue color difference signals, and the luminance signal is added to the red, blue, and green color difference signals, and the red, blue, and green signals are generated. The luminance signal generated from the luminance equation is compared with the original luminance signal.

When the two luminance signals match, the signal system is automatically determined to be the signal system of the assumed luminance equation. The function is to automatically determine the luminance equation in the signal system.

According to a second aspect of the present invention, there are provided three adder circuits for inputting a luminance signal of a color television receiver and red, blue and green color difference signals, and a red and blue color difference signal. A green color difference signal matrix circuit capable of changing a matrix coefficient to be input, a luminance signal matrix circuit to receive red, blue, and green signals as inputs, and a generated luminance signal and an original luminance signal as inputs. And a microcomputer that receives the output of the comparison circuit as an input. This is a circuit for automatically determining a luminance equation of a color television receiver. It has the effect of automatically determining.

According to a third aspect of the present invention, there is provided an amplifying circuit for a color television receiver, to which a red color difference signal is input, an amplifying circuit to which a blue color difference signal is input, a luminance signal, a red signal, Three adder circuits for inputting blue and green color difference signals, a green color difference signal matrix circuit capable of changing matrix coefficients for inputting red and blue color difference signals, and red, blue, and green A color signal comprising: a luminance signal matrix circuit that receives a signal; a comparison circuit that receives the generated luminance signal and the original luminance signal; and a microcomputer that receives an output of the comparison circuit as an input. This is a circuit for automatically judging a luminance equation of a television receiver, and has an operation of automatically judging a luminance equation in a signal system and an operation of realizing a correct color signal reproduction.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a block diagram of a luminance equation automatic discrimination circuit of a color television receiver according to claims 1 and 2 of the present invention.

In FIG. 1, reference numeral 1 denotes an adding circuit. Reference numeral 2 denotes an adding circuit. Reference numeral 3 denotes an adding circuit. Reference numeral 4 denotes a matrix circuit for a green color difference signal. Reference numeral 5 denotes a matrix coefficient switching circuit for a green color difference signal. Reference numeral 6 denotes a luminance signal matrix circuit. Reference numeral 7 denotes a luminance signal matrix coefficient switching circuit. Reference numeral 9 denotes a microcomputer.

Next, the operation will be described with reference to FIG.
The luminance signal Y and the red color difference signal RY are added to the addition circuit 1 of FIG.
And outputs a red signal R.

A luminance signal Y and a blue color difference signal BY are input to the adder circuit 2 of FIG. 1 and a blue signal B is output. The red color difference signal RY and the blue color difference signal BY are input to the green color difference signal GY matrix circuit 4, and the green color difference signal GY is output. At this time, the coefficient of the GY generation matrix is
The matrix coefficient corresponding to one of the luminance equations is G
-It is switched by the Y matrix coefficient switching circuit 5. For example, as a luminance equation, in the case of the NTSC system, Y = 0.30R + 0.59G + 0.11B.

In the case of high definition, Y = 0.2125R
+ 0.7154G + 0.0721B. For example, in the case of the NTSC system, the matrix of the green color difference signals GY formed by the red color difference signals RY and the blue color difference signals BY is GY = −0.51 (R− Y) -0.1
9 (BY).

The green color difference signal G-
The luminance signal Y and the luminance signal Y are input to the adder circuit 3 to output a green signal G. The red signal R, the blue signal B, and the green signal G are input to the luminance signal Y matrix circuit 6, and the luminance signal Y is output.

At this time, the luminance equation to be used is the same as that set by the green color difference signal GY matrix coefficient switching circuit 5, and is set by the luminance equation coefficient switching circuit 7.

The luminance signal output from the luminance signal Y matrix circuit 6 and the original input luminance signal are input to a comparison circuit 8, and the output is input to a microcomputer 9. When the luminance equation set by the GY matrix switching circuit 5 and the luminance equation switching circuit 7 matches the luminance equation of the received signal, the output of the comparison circuit 8 becomes zero. If different, there will be some voltage.

If they differ, the coefficients of the GY matrix switching circuit 5 and the luminance equation switching circuit 7 are switched to those of another luminance equation, and the same operation is repeated.
According to the above configuration, the luminance equation of the received signal can be automatically and efficiently determined within a short time. Also, correct color signal reproduction is realized.

(Embodiment 2) FIG. 2 shows a third embodiment of the present invention.
3 is a block diagram of a luminance equation automatic discrimination circuit of the color television receiver described in FIG.

In FIG. 2, reference numeral 1 denotes an adding circuit. Reference numeral 2 denotes an adding circuit. Reference numeral 3 denotes an adding circuit. Reference numeral 4 denotes a matrix circuit for a green color difference signal. Reference numeral 5 denotes a matrix coefficient switching circuit for a green color difference signal. Reference numeral 6 denotes a luminance signal matrix circuit. Reference numeral 7 denotes a luminance signal matrix coefficient switching circuit. Reference numeral 8 is a comparison circuit. Reference numeral 9 denotes a microcomputer. Reference numeral 10 denotes an amplifier circuit for a red color difference signal. Reference numeral 11 denotes an amplifier circuit for a blue color difference signal.

Next, the operation will be described with reference to FIG.
FIG. 2 is obtained by adding a red color difference signal amplifier circuit 10 and a blue color difference signal amplifier circuit 11 to FIG. 1 used in the description of the first embodiment, and the basic operation is the same.

In the luminance equation automatic discrimination circuit described in the first embodiment, after the used luminance equation is determined with a certain probability, the red color difference signal amplification circuit 10 and the blue color difference signal amplification are performed. By controlling the amplification degree in the circuit 11, the output of the comparison circuit 8 is surely reduced to zero.

In this way, the luminance equation can be automatically determined, and the level error between the red and blue color difference signals in the transmission system can be corrected to realize accurate color signal reproduction.

[0023]

As described above, according to the circuit for automatically determining the luminance equation of a color television receiver according to the present invention, a method for automatically determining the luminance equation of an input signal system in a color television receiver is as follows. Assuming a luminance equation of either system, a green color difference signal is generated from a red and blue color difference signal, and a luminance signal is generated by adding the red and blue and green color difference signals. From the blue and green signals, a luminance signal generated from the assumed luminance equation is compared with the original luminance signal.

When the two luminance signals coincide with each other, it is possible to automatically determine the signal system of the assumed luminance equation, and correct the level error of the red and blue color difference signals in the transmission system to obtain an accurate signal. Reproduction of a color signal can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a luminance equation automatic discrimination circuit of a color television receiver according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of a luminance equation automatic discrimination circuit of the color television receiver according to Embodiment 2 of the present invention.

[Explanation of symbols]

 1, 2, 3 Adder circuit 4 Green color difference signal matrix circuit 5 Green color difference signal matrix coefficient switching circuit 6 Luminance signal matrix circuit 7 Luminance signal matrix coefficient switching circuit 8 Comparison circuit 9 Microcomputer 10 Red color difference signal Amplifier circuit 11 Amplifier circuit for blue color difference signal

Claims (3)

[Claims] Assuming a luminance equation of one system, a green color difference signal is generated from red and blue color difference signals, and is generated by adding a luminance signal and red, blue and green color difference signals. From the red and blue and green signals, compare the luminance signal generated from the assumed luminance equation with the original luminance signal,
A luminance equation automatic discrimination circuit for a color television receiver, characterized in that when two luminance signals match, the signal system of the assumed luminance equation is determined. 2. A three-color addition circuit that receives a luminance signal and red, blue, and green color difference signals as inputs, a green color difference signal matrix circuit that receives a red and blue color difference signal, and that can change a matrix coefficient. A luminance signal matrix circuit that receives red, blue, and green signals, a comparison circuit that receives the generated luminance signal and the original luminance signal, and a microcomputer that receives the output of the comparison circuit as an input. A circuit for automatically determining a luminance equation of a color television receiver. 3. An amplifier circuit having a red color difference signal as input,
An amplifier circuit that receives a blue color difference signal, three adder circuits that receive a luminance signal and red, blue, and green color difference signals, and a green that can change a matrix coefficient that receives a red and blue color difference signal. A color difference signal matrix circuit, a luminance signal matrix circuit that receives red, blue, and green signals as input, a comparison circuit that receives the generated luminance signal and the original luminance signal, and an output of the comparison circuit. A luminance equation automatic discrimination circuit for a color television receiver, comprising: