Digital filter for picture data and digital filter system
First Claim
1. A digital filter for picture data comprising:
- a first low-pass filter having relatively steep cut-off characteristics for filtering input digital picture data;
a second low-pass filter having relatively moderate cut-off characteristics for filtering said input digital picture data;
mixing means for mixing the digital picture data filtered by said first and second low-pass filters;
step detection means for detecting changes in step-like values of the input digital picture data and for producing an output representation of the detected changes; and
control means for controlling the mixing ratio of the filtered digital picture data from said first and second low-pass filters by said mixing means based on the output of said step detection means.
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Accused Products
Abstract
A digital filter for picture data is disclosed which has a first low-pass filter having relatively steep cut-off characteristics for filtering input digital picture data, a second low-pass filter having relatively moderate cut-off characteristics for filtering input digital picture data, a mixing unit for mixing digital picture data filtered by the first and second low-pass filters, a step detecting unit for detecting changes in step-like values of the input picture data, and a control unit for controlling the mixing ratio of the digital picture data from the first and second low-pass filters by the mixing unit based on step detection outputs of the step detection unit. There is also provided a digital filter system for color picture data having the digital filter for each color.
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Citations
26 Claims
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1. A digital filter for picture data comprising:
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a first low-pass filter having relatively steep cut-off characteristics for filtering input digital picture data; a second low-pass filter having relatively moderate cut-off characteristics for filtering said input digital picture data; mixing means for mixing the digital picture data filtered by said first and second low-pass filters; step detection means for detecting changes in step-like values of the input digital picture data and for producing an output representation of the detected changes; and control means for controlling the mixing ratio of the filtered digital picture data from said first and second low-pass filters by said mixing means based on the output of said step detection means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A digital filter for picture data comprising:
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a first low-pass filter of relatively broad bandwidth for filtering input digital picture data; a second low-pass filter of a relatively narrow bandwidth for filtering said input digital picture data; mixing means for mixing the digital picture data filtered by said first and second low-pass filters; step detecting means for detecting changes in step-like values of the input digital picture data and for producing an output representation of the detected changes; and control means for controlling the mixing ratio of the filtered digital data from said first and second low-pass filters by said mixing means based on the output of said step detection means. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A digital filter system for picture data having a digital filter for each of input digital picture data of respective colors, each digital filter including:
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a first low-pass filter having relatively steep cut-off characteristics for filtering the input digital picture data; a second low-pass filter having relatively moderate cut-off characteristics for filtering said input digital picture data; mixing means for mixing the digital picture data filtered by said first and second low-pass filters; step detection means for detecting changes in step-like values of the input digital picture data and for producing an output representative of the detected changes; and control means for controlling the mixing ratio of the filtered digital picture data from said first and second low-pass filters by said mixing means based on the output of said step detection means. - View Dependent Claims (18, 19, 20, 21)
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22. A digital filter system for picture data having a digital filter for each of input digital picture data of respective colors, each digital filter comprising:
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a first low-pass filter of relatively broad bandwidth for filtering said input digital picture data; a second low-pass filter of a relatively narrow bandwidth for filtering said input digital picture data; mixing means for mixing the digital picture data filtered by said first and second low-pass filters; step detection means for detecting changes in step-like values of the input digital picture data and for producing an output representative of the detected changes; and control means for controlling the mixing ratio of the filtered digital data from said first and second low-pass filters by said mixing means based on the output of said step detection means. - View Dependent Claims (23, 24, 25, 26)
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Specification