Picture-quality improving circuit

Claim 2

A picture-quality improving circuit comprising: means for generating a chroma edge signal on the basis of a color signal, the chroma edge signal representing a chroma edge; means for generating a luminance edge signal on the basis of a luminance signal, the luminance edge signal representing a luminance edge; means for detecting the chroma edge signal; means for differentiating an output signal from the detecting means; means for determining whether or not the luminance edge signal and an output signal from the differentiating means are in a same polarity; means for selecting the luminance edge signal when the luminance edge signal and the output signal from the differentiating means are in the same polarity and, for selecting a reference signal when the luminance edge signal and the output signal from the differentiating means are not in the same polarity; means for multiplying the chroma edge signal and an output signal from the selecting means; and means for adding an output signal from the multiplying means to the color signal to yield an enhanced color signal.

Claim 3

The picture-quality improving circuit of claim 1 wherein the chroma-edge-signal generating means comprises first and second subtracters, and a cascade combination of first, second, and third equalizers; the color signal is fed to an input terminal of the first equalizer and a first input terminal of the first subtracter; an output signal from the first equalizer is fed to an input terminal of the second equalizer and a first input terminal of the second subtracter; an output signal from the second equalizer is fed to a second input terminal of the first subtracter, an input terminal of the third equalizer, and the adding means; an output signal from the third equalizer is fed to a second input terminal of the second subtracter; an output signal from the first subtracter is fed to the detecting means; and an output signal from the second subtracter is fed to the multiplying means.

Claim 4

A picture-quality improving circuit comprising: means for generating a chroma edge signal on the basis of a color signal, the chroma edge signal representing a chroma edge; means for generating a luminance edge signal on the basis of a luminance signal, the luminance edge signal representing a luminance edge; means for detecting the chroma edge signal; means for differentiating an output signal from the detecting means; means for determining whether or not the luminance edge signal and an output signal from the differentiating means are in a same polarity; first selecting means for selecting the luminance edge signal when the luminance edge signal and the output signal from the differentiating means are in the same polarity, and for selecting a reference signal when the luminance edge signal and the output signal from the differentiating means are not in the same polarity; second selecting means for selecting one of the output signal from the differentiating means and an output signal from the first selecting means which is greater in amplitude than the other; means for multiplying the chroma edge signal and an output signal from the second selecting means; and means for adding an output signal from the multiplying means to the color signal to yield an enhanced color signal.

Claim 5

A picture-quality improving circuit comprising: means for generating a chroma edge signal on the basis of a color signal, the chroma edge signal representing a chroma edge; means for generating a luminance edge signal on the basis of a luminance signal, the luminance edge signal representing a luminance edge; means for detecting the chroma edge signal; means for differentiating an output signal from the detecting means; means for determining whether or not the luminance edge signal and an output signal from the differentiating means are in a same polarity; first selecting means for selecting the luminance edge signal when the luminance edge signal and the output signal from the differentiating means are in the same polarity, and for selecting a reference signal when the luminance edge signal and the output signal from the differentiating means are not in the same polarity; second selecting means for selecting one of the output signal from the differentiating means and an output signal from the first selecting means which is greater in amplitude than the other; means for multiplying the chroma edge signal and an output signal from the second selecting means; and means for adding an output signal from the multiplying means to the color signal to yield an enhanced color signal.

Claim 6

The picture-quality improving circuit of claim 3 wherein the chroma-edge-signal generating means comprises first and second subtracters, and a cascade combination of first, second, and third equalizers; the color signal is fed to an input terminal of the first equalizer and a first input terminal of the first subtracter; an output signal from the first equalizer is fed to an input terminal of the second equalizer and a first input terminal of the second subtracter; an output signal from the second equalizer is fed to a second input terminal of the first subtracter, an input terminal of the third equalizer, and the adding means; an output signal from the third equalizer is fed to a second input terminal of the second subtracter; an output signal from the first subtracter is fed to the detecting means; and an output signal from the second subtracter is fed to the multiplying means.

Claim 7

A picture-quality improving circuit comprising: means for generating a chroma edge signal on the basis of a color signal, the chroma edge signal representing a chroma edge; means for generating a luminance edge signal on the basis of a luminance signal, the luminance edge signal representing a luminance edge; means for detecting the chroma edge signal; means for differentiating an output signal from the detecting means; means for amplifying an output signal from the differentiating means; first adding means for adding an output signal from the amplifying means and the luminance edge signal; means for multiplying the chroma edge signal and an output signal from the first adding means; and second adding means for adding an output signal from the multiplying means to the color signal to yield an enhanced color signal.

Claim 8

A picture-quality improving circuit comprising: means for generating a chroma edge signal on the basis of a color signal, the chroma edge signal representing a chroma edge; means for generating a luminance edge signal on the basis of a luminance signal, the luminance edge signal representing a luminance edge; means for detecting the chroma edge signal; means for differentiating an output signal from the detecting means; means for amplifying an output signal from the differentiating means; first adding means for adding an output signal from the amplifying means and the luminance edge signal; means for multiplying the chroma edge signal and an output signal from the first adding means; and second adding means for adding an output signal from the multiplying means to the color signal to yield an enhanced color signal.

Claim 9

The picture-quality improving circuit of claim 5 wherein the chroma-edge-signal generating means comprises first and second subtracters, and a cascade combination of first, second, and third equalizers; the color signal is fed to an input terminal of the first equalizer and a first input terminal of the first subtracter; an output signal from the first equalizer is fed to an input terminal of the second equalizer and a first input terminal of the second subtracter; an output signal from the second equalizer is fed to a second input terminal of the first subtracter, an input terminal of the third equalizer, and the adding means; an output signal from the third equalizer is fed to a second input terminal of the second subtracter; an output signal from the first subtracter is fed to the detecting means; and an output signal from the second subtracter is fed to the multiplying means.

Claim 10

A picture-quality improving circuit comprising: means for detecting a luminance transition on the basis of a luminance signal; means for enhancing chroma edge characteristics of a color signal in accordance with the detected luminance transition; wherein the improvement comprises: means for detecting that the color signal and the luminance signal are uncorrelated in transition; and means for disabling the enhancing means when the color signal and the luminance signal are uncorrelated in transition.

Claim 11

A picture-quality improving circuit comprising: means for detecting a luminance transition on the basis of a luminance signal; means for enhancing chroma edge characteristics of a color signal in accordance with the detected luminance transition; wherein the improvement comprises: means for detecting that the color signal and the luminance signal are uncorrelated in transition; and means for disabling the enhancing means when the color signal and the luminance signal are uncorrelated in transition.

Claim 12

A chroma difference extractor comprising first and second subtracters, and a cascade combination of first, second, and third equalizers, wherein a color signal is fed to an input terminal of the first equalizer and a first input terminal of the first subtracter; an output signal from the first equalizer is fed to an input terminal of the second equalizer and a first input terminal of the second subtracter; an output signal from the second equalizer is fed to a second input terminal of the first subtracter and an input terminal of the third equalizer; and an output signal from the third equalizer is fed to a second input terminal of the second subtracter.

Claim 13

A chroma difference extractor comprising first and second subtracters, and a cascade combination of first, second, and third equalizers, wherein a color signal is fed to an input terminal of the first equalizer and a first input terminal of the first subtracter; an output signal from the first equalizer is fed to an input terminal of the second equalizer and a first input terminal of the second subtracter; an output signal from the second equalizer is fed to a second input terminal of the first subtracter and an input terminal of the third equalizer; and an output signal from the third equalizer is fed to a second input terminal of the second subtracter.