Pattern-adaptive digital comb filter for separation of a luminance and a color signal

A pattern-adaptive digital comb filter, comprising:

• comb filter means for providing first 1 H comb data and secod 1 H comb data by comb-filtering input video signals of three successive horizontal scanning lines, and for providing 2 H comb data by combining said first 1 H comb data with said second 1 H comb data;
• first low pass filter means for providing first correlation data by detecting low band transitions of luminance signals between horizontal scan lines in said first 1 H comb data;
• second low pass filter means for providing second correlation data by detecting low band transitions of luminance signals between horizontal scan lines in said second 1 H comb data;
• first absolute value means for providing first absolute values of said first correlation data;
• second absolute value means for providing second absolute values of said second correlation data;
• multiplexer means for providing one of said first 1 H comb data, said second 1 H comb data, and said 2 H comb data as selected comb data in dependence upon selection data;
• comb-filtering controller means for generating said selection data to select said 2 H comb data when both said first correlation data and said second correlation data are smaller than reference data, and to select a more highly correlated one of said first 1 H comb data and said second 1 H comb data by comprising said first absolute values to said second absolute values when at least one of said first correlation data and said second correlation data is larger than said reference data;
• and
• means for providing luminance signals and color signals by separating said luminance signals from said input vide signals in dependence upon said selected comb data.

A pattern-adaptive digital comb filter, comprising:

• comb filter means for providing first 1 H comb data and second 1 H comb data by comb-filtering input video signals of three successive horizontal scanning lines, and for providing 2 H comb data by combining said first 1 H comb data with said second 1 H comb data;
• means for providing first correlation data by detecting low band transitions of luminance signals between horizontal scan line pairs in said first 1 H comb data, and for providing second correlation data by detecting low band transitions of luminance signals between horizontal scan line pairs in said second 1 H comb data;
• multiplexer means for providing one of said first 1 H comb data, said second 1 H comb data, said 2 H comb data, and said input video signals as selected video data in dependence upon selection data;
• controller means for generating said selection data so that said multiplexer means provides said input video signals in response to reception of an irregular signal indicative of said input video signal being irregular, provides said 2 H comb data when both said first correlation data and said second correlation data are smaller than reference data, and provides a more highly correlated one of said first 1 H comb data and said second 1 H comb data in response to comparisons of said first correlation data to said second correlation data when at least one of said first correlation data and said second correlation data is larger than said reference data;
• bandpass filter means for bandpass filtering said selected video data to generate filtered video data;
• and
• luminance signal generating means for separating luminance signals from said input video signals by subtracting said filtered video data from said input video signals.

A pattern-adaptive digital comb filter, comprising:

• first delay means for providing first delayed video signals by delaying input video signals for a first horizontal scan period;
• second delay means for providing second delayed video signals by delaying said first delayed video signals for a second horizontal scan period;
• first subtracter means for obtaining first differences between said input video signals and said first delayed video signals to provide first 1 H comb data;
• second subtracter means for obtaining second differences between said first delayed video signals and said second delayed video signals to provide second 1 H comb data;
• adder means for obtaining sums of said first 1 H comb data to said second 1 H comb data to provide 2 H comb data;
• means for providing first correlation data by detecting low band transitions of luminance signals between horizontal scan line pairs in said first 1 H comb data, and for providing second correlation data by detecting low band transitions of luminance signals between horizontal scan line pairs in said second 1 H comb data;
• multiplexer means for providing one said first 1 H comb data, said second 1 H comb data, said 2 H comb data, and said first delayed video signals as selected video data in dependence upon selection data;
• means for providing first absolute values of said first correlation data, and for providing second absolute values of said second correlation data;
• controller means for generating said selection data so that said multiplexer means provides said first delayed video signals in response to reception of an irregular signal indicative of said input video signal being irregular, provides said 2 H comb data when both said first absolute values and said second absolute values are smaller than reference data, and provides a more highly correlated one of said first 1 H comb data and said second 1 H comb data in response to comparisons of said first absolute values with said second absolute values when at least one of said first absolute values and said second absolute values is larger than said reference data, said controller means comprising:
• a first comparator for providing first comparison results by comparing said first absolute values with said second absolute values,
• a second comparator for providing second comparison results by comparing said first absolute values data with said reference data;
• a third comparator for providing third comparison results by comparing said second absolute values with said reference data,
• first gate means for logically combining said second comparison results and said third comparison results to generate first logic results,
• second gate means for logically combining said first logic results and said first comparison results to generate second logic results,
• third gate means for logically combining said first logic results and said first comparison results to generate third logic results,
• fourth gate means for logically combining said second logic results and said irregular signal to generate first parts of said selection data, and
• fifth gate means for logically combining said third logic results and said irregular signal to generate second parts of said selection data;
• bandpass filter means for bandpass filtering said selected video data to generate filtered video data;
• and
• luminance signal generating means for separating luminance signals from said first delayed video signals in dependence upon said filtered video data.

A digital comb filter, comprising:

• comb filter means coupled to receive input video signals, for providing first delayed video signals and second delayed video signals by comb-filtering said input video signals, and for providing third video signals by combining said first and second delayed video signals;
• correlation means for providing first and second correlation signals by detecting low band transitions of luminance signals between horizontal scan line pairs in said first and second delayed video signals, respectively;
• selection means for selecting one of said first delayed video signals, said second delayed video signals, said third video signals, and said input video signals as selected video signals in dependance upon selection signals;
• controller means for generating said selection signals for enabling said selection means to select said input video signals as said selected video signals in response to reception of an irregular signal indicative of said input video signal containing errors, select said third video signals as said selected video signals when both said first correlation signals and said second correlation signals are smaller than reference signals, and select a higher correlated one of said first delayed video signals and said second delayed video signals as said selected video signals in dependence upon comparisons of said first correlation signals with said second correlation signals when at least one of said first correlation signals and said second correlation signals is larger than said reference signals;
• and
• means for providing color signals from said selected video signals and providing luminance signals from said input video signals in dependence upon said color signals.