A circuit for processing a color difference signal by utilizing the change of a luminance signal

Claim 2

A circuit arrangement for enhancing a color difference signal of a video signal, comprising: (a) filter means responsive to a luminance signal of said video signal for limiting the bandwidth of said luminance signal; (b) first delay circuit means for delaying an output signal from said filter means; (c) first differentiation circuit means for differentiating an output signal from said first delay circuit means; (d) detector means for detecting an output signal from said first differentiation circuit means; (e) slicer means responsive to an output signal from said detector means for slicing said output signal from said detector means at a predetermined slice level thereof; (f) second differentiation circuit means for differentiating an output signal from said slicer means; (g) comparator set means responsive to an output signal from said second differentiation circuit means for producing first and second signals by comparing said output signal from said second differentiation circuit means with two predetermined signal levels; (h) second delay circuit means for delaying said color difference signal; (i) first sample-and-hold circuit means for holding said output signal from said second delay circuit means in response to said first signal thereby outputting a third signal indicative of a held level of said output signal from said second delay circuit means; (j) second sample-and-hold circuit means for holding said color difference signal in response to said second signal thereby outputting a fourth signal indicative of a held level of said color difference signal; and (k) switching circuit means responsive to said third signal, said output signal from said second delay circuit means, and said fourth signal for selecting one of these three signals in accordance with combination of said first and second signals thereby outputting a signal which is selected therein.

Claim 3

A circuit arrangement for enhancing a color difference signal of a video signal, comprising: (a) filter means responsive to a luminance signal of said video signal for limiting the bandwidth of said luminance signal; (b) differentiation circuit means for differentiating an output signal from said filter means; (c) detector means for detecting an output signal from said differentiation circuit means; (d) comparator means responsive to an output signal from said detector means for comparing said output signal from said detector means with a predetermined threshold level thereby outputting a first signal; (e) delay circuit means for delaying said color difference signal; (f) quadratic differentiation circuit means responsive to an output signal from said delay circuit means for differentiating said output signal from said delay circuit means two times; (g) switching circuit means responsive to said first signal and an output signal from said quadratic differentiation circuit means for outputting said output signal from said quadratic differentiation cirucit in response to said first signal; and (h) subtractor means for subtracting an output signal of said switching circuit means from said output signal of said delay circuit means thereby producing a signal indicative of an enhanced color difference signal.

Claim 4

A circuit arrangement for enhancing a color difference signal of a video signal, comprising: (a) filter means responsive to a luminance signal of said video signal for limiting the bandwidth of said luminance signal; (b) differentiation circuit means for differentiating an output signal from said filter means; (c) detector means for detecting an output signal from said differentiation circuit means; (d) comparator means responsive to an output signal from said detector means for comparing said output signal from said detector means with a predetermined threshold level thereby outputting a first signal; (e) delay circuit means for delaying said color difference signal; (f) quadratic differentiation circuit means responsive to an output signal from said delay circuit means for differentiating said output signal from said delay circuit means two times; (g) switching circuit means responsive to said first signal and an output signal from said quadratic differentiation circuit means for outputting said output signal from said quadratic differentiation cirucit in response to said first signal; and (h) subtractor means for subtracting an output signal of said switching circuit means from said output signal of said delay circuit means thereby producing a signal indicative of an enhanced color difference signal.

Claim 5

A circuit arrangement for enhancing a color difference signal of a video signal, comprising: (a) filter means responsive to a luminance signal of said video signal for limiting the bandwidth of said luminance signal; (b) differentiation circuit means for differentiating an output signal from said filter means; (c) detector means for detecting an output signal from said differentiation circuit means; (d) comparator means responsive to an output signal from said detector means for comparing said output signal from said detector means with a predetermined threshold level thereby outputting a first signal; (e) delay circuit means for delaying said color difference signal; (f) quadratic differentiation circuit means responsive to an output signal from said delay circuit means for differentiating said output signal from said delay circuit means two times; (g) switching circuit means responsive to said first signal and an output signal from said quadratic differentiation circuit means for outputting said output signal from said quadratic differentiation cirucit in response to said first signal; (h) amplifier means for amplifying an output signal from said switching circuit; and (i) subtractor means for subtracting an output signal of said amplifier means from said output signal of said delay circuit means thereby producing a signal indicative of an enhanced color difference signal.

Claim 6

A circuit arrangement for enhancing a color difference signal of a video signal, comprising: (a) filter means responsive to a luminance signal of said video signal for limiting the bandwidth of said luminance signal; (b) differentiation circuit means for differentiating an output signal from said filter means; (c) detector means for detecting an output signal from said differentiation circuit means; (d) comparator means responsive to an output signal from said detector means for comparing said output signal from said detector means with a predetermined threshold level thereby outputting a first signal; (e) delay circuit means for delaying said color difference signal; (f) quadratic differentiation circuit means responsive to an output signal from said delay circuit means for differentiating said output signal from said delay circuit means two times; (g) switching circuit means responsive to said first signal and an output signal from said quadratic differentiation circuit means for outputting said output signal from said quadratic differentiation cirucit in response to said first signal; (h) amplifier means for amplifying an output signal from said switching circuit; and (i) subtractor means for subtracting an output signal of said amplifier means from said output signal of said delay circuit means thereby producing a signal indicative of an enhanced color difference signal.

Claim 7

A digital circuit arrangement for enhancing color difference signal data derived from video signal data, comprising: (a) low-pass filter means responsive to luminance signal data of said video signal data for limiting the bandwidth of said luminance signal data; (b) first difference circuit means responsive to output signal data from said low-pass filter means for differentiating said output signal data from said low-pass filter means; (c) ROM circuit means responsive to said output data from said first difference circuit means for looking up a ROM table in said ROM circuit means thereby outputting data in response to said output data from said first difference circuit means; (d) second difference circuit means responsive to output signal data from said ROM circuit means for differentiating said output signal data from said ROM circuit means; (e) first magnitude comparator means for comparing output signal data from said second difference circuit means with two predetermined threshold level data thereby outputting a first signal; (f) second magnitude comparator means for comparing said output signal data from said second difference circuit means with two predetermined threshold level data thereby outputting a second signal; (g) delay circuit means for delaying said color difference signal data; (h) first latch means for latching said output signal data from said delay circuit means in response to said first signal thereby outputting first signal data indicative of latched level of said output signal from said delay circuit means; (i) second latch means for latching said color difference signal data in response to said second signal thereby outputting second signal data indicative of latched level of said color difference signal data; and (j) data selector means responsive to said first signal data, said output signal data from said delay circuit means, and said second signal data for selecting one of these three signal data in accordance with combination of said first and second signals thereby outputting signal data which is selected therein.

Claim 8

A digital circuit arrangement for enhancing color difference signal data derived from video signal data, comprising: (a) low-pass filter means responsive to luminance signal data of said video signal data for limiting the bandwidth of said luminance signal data; (b) first difference circuit means responsive to output signal data from said low-pass filter means for differentiating said output signal data from said low-pass filter means; (c) ROM circuit means responsive to said output data from said first difference circuit means for looking up a ROM table in said ROM circuit means thereby outputting data in response to said output data from said first difference circuit means; (d) second difference circuit means responsive to output signal data from said ROM circuit means for differentiating said output signal data from said ROM circuit means; (e) first magnitude comparator means for comparing output signal data from said second difference circuit means with two predetermined threshold level data thereby outputting a first signal; (f) second magnitude comparator means for comparing said output signal data from said second difference circuit means with two predetermined threshold level data thereby outputting a second signal; (g) delay circuit means for delaying said color difference signal data; (h) first latch means for latching said output signal data from said delay circuit means in response to said first signal thereby outputting first signal data indicative of latched level of said output signal from said delay circuit means; (i) second latch means for latching said color difference signal data in response to said second signal thereby outputting second signal data indicative of latched level of said color difference signal data; and (j) data selector means responsive to said first signal data, said output signal data from said delay circuit means, and said second signal data for selecting one of these three signal data in accordance with combination of said first and second signals thereby outputting signal data which is selected therein.

Claim 9

A circuit arrangement as claimed in Claim 4, wherein said filter means is an FIR filter.

Claim 10

A digital circuit arrangement as claimed in Claim 4 wherein said first and second difference circuit means respectively includes first and second latches and first and second subtractors, said first latch being responsive to said output signal data from said low-pass filter means, said first subtractor being responsive to output signal data from said first latch and said output signal data from said low-pass filter thereby producing said output signal data from said first difference circuit means, and said second latch being responsive to said output signal data from said ROM circuit means, said second subtractor being responsive to output signal data from said second latch and said output signal data from said ROM circuit means thereby producing said output signal data from said second difference circuit means.

Claim 11

A digital circuit arrangement for enhancing color difference signal data derived from video signal data, comprising: (a) low-pass filter means responsive to luminance signal data of said video signal data for limiting the bandwidth of said luminance signal data; (b) first difference circuit means responsive to output signal data from said low-pass filter means for differentiating said output signal data from said low-pass filter means; (c) ROM circuit means responsive to said output data from said first difference circuit means for looking up a ROM table in said ROM circuit means thereby outputting a signal indicative of a switching signal in response to said output data from said first difference circuit means; (d) delay circuit means for delaying said color difference signal data; (e) latch means responsive to output signal data from said delay circuit means for latching said output signal data from said delay circuit means; (f) second difference circuit means responsive to said output signal data from said delay circuit means for differentiating said output signal data from said delay circuit means two times thereby outputting first signal data indicative of difference signal data; and (g) switching circuit means for outputting said difference signal data from said second difference circuit means in response to said switching signal outputted from said ROM circuit means; and (h) adder means for substantially subtracting output signal data of said switching circuit means from output signal data of said latch means thereby outputting signal data indicative of enhanced color difference signal data.

Claim 12

A digital circuit arrangement for enhancing color difference signal data derived from video signal data, comprising: (a) low-pass filter means responsive to luminance signal data of said video signal data for limiting the bandwidth of said luminance signal data; (b) first difference circuit means responsive to output signal data from said low-pass filter means for differentiating said output signal data from said low-pass filter means; (c) ROM circuit means responsive to said output data from said first difference circuit means for looking up a ROM table in said ROM circuit means thereby outputting a signal indicative of a switching signal in response to said output data from said first difference circuit means; (d) delay circuit means for delaying said color difference signal data; (e) latch means responsive to output signal data from said delay circuit means for latching said output signal data from said delay circuit means; (f) second difference circuit means responsive to said output signal data from said delay circuit means for differentiating said output signal data from said delay circuit means two times thereby outputting first signal data indicative of difference signal data; and (g) switching circuit means for outputting said difference signal data from said second difference circuit means in response to said switching signal outputted from said ROM circuit means; and (h) adder means for substantially subtracting output signal data of said switching circuit means from output signal data of said latch means thereby outputting signal data indicative of enhanced color difference signal data.

Claim 13

A digital circuit arrangement as claimed in Claim 7, wherein said second difference circuit means includes first and second latches, and first and second adders, said first latch being responsive to said output signal data from said delay circuit means, said second latch being responsive to output signal data from said first latch, said first adder being responsive to said output signal data from said delay circuit means and ouput signal data from said second latch, said second adder being responsive to said output signal data from said first latch and output signal data from said first adder thereby outputting said first signal data.