US 5,093,715 A · Adaptive comb filter for separating at least one component of a video signal

An adaptive comb filter for separating at least one component of a video signal, comprising:

a filter input terminal for receiving said video signal;
first and second signal delay means for delaying signals supplied to respective input terminals thereof and providing respective delayed input signals at respective output terminals thereof, the input terminal of the first signal delay means being coupled with said filter input terminal and the output terminal thereof being coupled with the input terminal of the second delay means;
first and second signal subtracting means for each producing output difference signals at a respective output terminal thereof representing a difference between signals supplied to a respective plurality of input terminals thereof, first and second input terminals of the first signal subtracting means each being coupled with a respective one of the input and output terminals of said first signal delay means and first and second input terminals of the second signal subtracting means each being coupled with a respective one of the input and output terminals of said second signal delay means;
first signal adding means for producing a summation signal at an output terminal thereof representing a summation of signals received at first and second input terminals thereof, said first and second input terminals of said first signal adding means being respectively coupled with said output terminals of said first and second signal subtracting means;
first switching means for selectively providing one of a plurality of input signals received at respective input terminals thereof to an output terminal thereof, said first switching means having first and second input terminals respectively coupled with said output terminals of said first and second signal subtracting means, a third input terminal coupled with the output terminal of said first signal adding means and a fourth input terminal coupled with the output terminal of said first signal delay means, the output terminal of said switching means being operative to provide a first component of said video signal;
second and third signal adding means for each producing a summation signal at a respective output terminal thereof representing a summation of signals received at respective first and second input terminals thereof, said first input terminal of each of said second and third signal adding means being coupled with the output terminal of said first signal delay means, said second input terminal of the second signal adding means being coupled with said filter input terminal, and said second input terminal of the third signal adding means being coupled with the output terminal of the second signal delay means;
first and second absolute value means for each producing an output signal at a respective output terminal thereof representing an absolute value of a signal received at a respective input terminal thereof, the input terminals of said first and second absolute value means being respectively coupled with the output terminals of said second and third signal adding means, respectively;
and
controlling means for controlling the selective provision of input signals by said first switching means to its output terminal based upon a comparison of the magnitudes of the output signals produced at the output terminals of said first and second absolute value means.

6 more elements

An adaptive comb filter for separating at least a chrominance signal component of a video signal, comprising:

a filter input terminal for receiving said video signal
first and second signal delay means for delaying signals supplied to respective input terminals thereof and providing respective delayed input signals at respective output terminals thereof, the input terminal of the first signal delay means being coupled with said filter input terminal and the output terminal thereof being coupled with the input terminal of the second delay means;
first and second signal subtracting means for each producing output difference signals at a respective output terminal thereof representing a difference between signals supplied to a respective plurality of input terminals thereof, first and second input terminals of the first signal subtracting means each being coupled with a respective one of the input and output terminals of said first signal delay means and first and second input terminals of the second signal subtracting means each being coupled with a respective one of the input and output terminals of said second signal delay means;
first signal adding means for producing a summation signal at an output terminal thereof representing a summation of signals received at first and second input terminals thereof, said first and second input terminals of said first signal adding means being respectively coupled with said output terminals of said first and second signal subtracting means;
chrominance band pass filtering means for providing output signals at an output terminal thereof representing components of input signals received at an input terminal of said chrominance band pass filtering means such that components of said input signals outside of a predetermined pass band for a chrominance signal component of said video signal are attenuated at said output terminal of the chrominance band pass filtering means, the input terminal of said chrominance band pass filtering means being coupled with the output terminal of said first signal delay means,
first switching means for selectively providing one of a plurality of input signals received at respective input terminals thereof to an output terminal thereof, said first switching means having first and second input terminals respectively coupled with said output terminals of said first and second signal subtracting means, a third input terminal coupled with the output terminal of said first signal adding means and a fourth input terminal coupled with the output terminal of said chrominance band pass filtering means, the output terminal of said switching means being operative to provide a first component of said video signal;
second and third signal adding means for each producing a summation signal at a respective output terminal thereof representing a summation of signals received at respective first and second input terminals thereof, said first input terminal of each of said second and third signal adding means being coupled with the output terminal of said first signal delay means, said second input terminal of the second signal adding means being coupled with said filter output terminal, and said second input terminal of the third signal adding means being coupled with the output terminal of the second signal delay means;
first and second absolute value means for each producing an output signal at a respective output terminal thereof representing an absolute value of a signal received at a respective input terminal thereof, the input terminals of said first and second absolute value means being respectively coupled with the output terminals of said second and third signal adding means, respectively;
and
controlling means for controlling the selective provision of input signals by said first switching means to its output terminal based upon a relative value of the output signals produced at the output terminals of said first and second absolute value means;
said controlling means including correlation detecting means for detecting horizontal correlation of luminance signal components in the summation signals produced at the output terminals of said second and third signal adding means, said controlling means being operative to control said first switching means to inhibit selection thereby of input signals from said chrominance band pass filtering means upon detection of said horizontal correlation of luminance signal components in said summation signals.

8 more elements

An adaptive comb filter for separating a chrominance signal component and a luminance component of a video signal, comprising:

a filter input terminal for receiving said video signal;
first and second signal delay means for delaying signals supplied to respective input terminals thereof and providing respective delayed input signals at respective output terminals thereof, the input terminal of the first signal delay means being coupled with said filter input terminal and the output terminal thereof being coupled with the input terminal of the second delay means;
first and second signal subtracting means for each producing output difference signals at a respective output terminal thereof representing a deference between signals supplied to a respective plurality of input terminals thereof, first and second input terminals of the first signal subtracting means each being coupled with a respective one of the input and output terminals of said first signal delay means and first and second input terminals of the second signal subtracting means each being coupled with a respective one of the input and output terminals of said second signal delay means;
first signal adding means for producing a summation signal at an output terminal thereof representing a summation of signals received at first and second input terminals thereof, said first and second input terminals of said first signal adding means being respectively coupled with said output terminals of said first and second signal subtracting means;
first switching means for selectively providing one of a plurality of input signals received at respective input terminals thereof to an output terminal thereof, said first switching means having first and second input terminals respectively coupled with said output terminals of said first and second signal subtracting means, a third input terminal coupled with the output terminal of said first signal adding means and a fourth input terminal coupled with the output terminal of said first signal delay means, the output terminal of said switching means being operative to provide a first component of said video signal;
second and third signal adding means for each producing a summation signal at a respective output terminal thereof representing a summation of signals received at respective first and second input terminals thereof, said first input terminal of each of said second and third signal adding means being coupled with the output terminal of said first signal delay means, said second input terminal of the second signal adding means being coupled with said filter input terminal, and said second input terminal of the third signal adding means being coupled with the output terminal of the second signal delay means;
first and second absolute value means for each producing an output signal at a respective output terminal thereof representing an absolute value of a signal received at a respective input terminal thereof, the input terminals of said first and second absolute value means being respectively coupled with the output terminals of said second and third signal adding means, respectively;
controlling means for controlling the selective provision of input signals by said first switching means to its output terminal based upon a relative value of the output signals produced at the output terminals of said first and second absolute value means;
third signal delay means for delaying said video signal by an interval substantially equal to a signal delay between said video signal and said first component of said video signal provided at the output terminal of said first switching means to provide a delayed video signal at an output terminal of said third signal delay means;
signal subtraction means for attenuating chrominance signal components in said delayed video signal by subtractive combination therewith of said first component of said video signal provided at the output terminal of said first switching means to provide a separated luminance signal component of said video signal at an output terminal of said signal subtraction means;
and
second switching means for selectively providing one of a plurality of input signals received at respective input terminals thereof to an output terminal of said second switching means, said second switching means having first and second input terminals coupled with the output terminals of said first and second signal subtracting means, respectively, and a third input terminal coupled with the output terminal of said first signal adding means, said second switching means being operative to provide a chrominance signal component of said video signal at the output terminal thereof;
said controlling means being operative to control said second switching means to select an input signal received at the third input terminal thereof as said chrominance signal component of said video signal when said controlling means controls said first switching means to select an input signal received at the fourth input terminal thereof.

10 more elements

An adaptive comb filter for separating at least one component of a video signal, comprising:

a filter input terminal for receiving said video signal;
first delay means for delaying said video signal by a first interval to produce a first delayed video signal;
second delay means for delaying said video signal by a second interval to produce a second delayed video signal;
first difference means for producing a first difference signal proportional to a difference between said video signal and said first delayed video signal;
second difference means for producing a second difference signal proportional to a difference between said first delayed video signal and said second delayed video signal;
first summing means for producing a first summation signal proportional to a summation of said first difference signal and said second difference signal;
first signal selecting means for controllably selecting one of said first difference signal, said second difference signal and said first summation signal as said at least one component of said video signal;
second summing means for producing a second summation signal proportional to a summation of said video signal and said first delayed video signal;
third summing means for producing a third summation signal proportional to a summation of said first delayed video signal and said second delayed video signal;
and
control means for controlling the selection of one of said first difference signal, said second difference signal and said first summation signal by said first signal selecting means based upon relative magnitudes of said second summation signal and said third summation signal.

8 more elements

An adaptive comb filter for separating at least a chrominance signal component of a video signal, comprising;

a filter input terminal for receiving said video signal;
first delay means for delaying said video signal by a first interval to produce a first delayed video signal;
first band pass filtering means for filtering said first delayed video signal to attenuate components thereof outside a first chrominance signal pass band to produce a band pass filtered signal;
second delay means for delaying said video signal by a second interval to produce a second delayed video signal;
first difference means for producing a first difference signal proportional to a difference between said video signal and said first delayed video signal;
second difference means for producing a second difference signal proportional to a difference between said first delayed video signal and said second delayed video signal;
first summing means for producing a first summation signal proportional to a summation of said first difference signal and said second difference signal;
first signal selecting means for controllably selecting one of said band pass filtered signals, said first difference signal, said second difference signal and said first summation signal as said at lest one component of said video signal;
second summing means for producing a second summation signal proportional to a summation of said video signal and said first delayed video signal;
third summing means for producing a third summation signal proportional to a summation of said first delayed video signal and said second delayed video signal;
correlation detecting means for detecting horizontal correlation of luminance signal components in said second summation signal and said third summation signal;
and
control means for controlling the selection of one of said first difference signal, said second difference signal and said first summation signal by said first signal selecting means based upon relative magnitudes of said second summation signal and said third summation signal, said control means being operative to control said first signal selecting means to inhibit selection of said band pass filtered signal upon detection said horizontal correlation of luminance signal components.

10 more elements

Adaptive comb filter for separating at least one component of a video signal

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Adaptive comb filter for separating at least one component of a video signal

Life of this patent

Abstract

Claims27