US 5,668,606 A · Contour restoration apparatus

Abstract

A contour restoration apparatus has a plurality of delay circuits connected in series. Maximum and minimum value detection circuits detect maximum and minimum values among an input video signal and output signals of the delay circuits. A mean value circuit is used to calculate a mean value of the of the maximum and minimum values. The mean value is subtracted from a delayed signal having a delay time of one-half of a delay time obtained from all the delay circuits. An adder is used to add the result of the subtraction to the delayed signal. A non-linear processing circuit processes the output of said adder and the maximum and minimum values. The non-linear circuit outputs the output signal of the adder, if the output signal of said adder is between the maximum value and the minimum value. A contour extraction circuit multiplies a signal located centrally among the input video signal, the output signals and the signals located before and after the input signal with a predetermined coefficient. An adder adds the multiplied signals. Another adder adds the result of multiplied signal and the centrally located signal. A contour amplitude circuit detects a difference between the maximum and minimum values and outputs a coefficient determined according to the difference detected. A mixer mixes the output of the non-linear processing circuit and the output of the another adder.

Claims5

Dependent claims

A contour restoration apparatus comprising an input terminal for a string of video signals having been sampled with first sampling interval,

a sampling rate converter for converting said string of video signals to a string of video signals having second sampling interval which is shorter than said first sampling interval,
a plurality of delay circuits connected to said sampling rate converter in series, each of said plurality of delay circuits having a delay time determined in accordance with said second sampling interval
a maximum value detection circuit for detecting a maximum value among output signal of said sampling rate converter and output signals of said plurality of delay circuits,
a minimum value detection circuit for detecting a minimum value among signals same as those input to said maximum value detection circuit,
a mean value circuit for calculating a mean value of output signals of said maximum and minimum value detection circuits,
a subtraction means for subtracting said mean value from an output signal of selected one of said plurality of delay circuits,
a gain controller for amplifying the output of said subtraction means with a predetermined gain,
an adder for adding the output of said gain controller and said output signal of selected one of said plurality of delay circuits, and
an output terminal for outputting the output of said adder as a contour restrated signal.

6 more elements

A contour restoration apparatus comprising:

an input terminal for video signals;
a plurality of delay circuits connected in series to said input terminal, each of said plurality of delay circuits having a predetermined delay time for a signal input thereto;
a maximum value detection circuit for detecting a maximum value among an input video signal and output signals of said plurality of delay circuits;
a minimum value detection circuit for detecting a minimum value among signals same as those input to said maximum value detection circuit;
a mean value circuit for calculating a mean value of output signals of said maximum and minimum value detection circuits;
a subtraction means for subtracting said mean value from a delayed signal output from one of said plurality of delay circuits, wherein said delayed signal has a delay time of one-half of a delay time obtained by a total of said plurality of said delay circuits;
a gain controller for amplifying the output of said subtraction means with a predetermined gain;
an adder for adding the output of said gain controller and said delayed signal input to said subtraction means;
a non-linear processing circuit to which the output of said adder and the maximum and minimum values output by said maximum and minimum detection circuits are input, said non-linear processing circuit outputting the maximum value if the output signal of said adder is larger than the maximum value, outputting the minimum value if the output signal of said adder is smaller than the minimum value, and outputting the output signal of said adder if the output signal of said adder is between the maximum value and the minimum value;
an output terminal for outputting the output of said non-linear processing circuit as a contour restored signal;
a location detection circuit for comparing an input video signal and output signals of said plurality of delay circuits with the maximum value detected by said maximum value detection value and comparing an input video signal and output signals of said plurality of delay circuits with the minimum value detection circuit;
and
said location detection circuit controlling the gain of the gain controller at zero if the maximum value and the minimum values are detected at the same side when seen from a location of the center signal among an input video signal and output signals of said plurality of delay circuits.

10 more elements

A contour restoration apparatus comprising:

an input terminal for video signals;
a plurality of delay circuits connected in series to said input terminal, each of said plurality of delay circuits having a predetermined delay time for a signal input thereto;
a maximum value detection circuit for detecting a maximum value among an input video signal and output signals of said plurality of delay circuits;
a minimum value detection circuit for detecting a minimum value among signals same as those input to said maximum value detection circuit;
a mean value circuit for calculating a mean value of output signals of said maximum and minimum value detection circuits;
a subtraction means for subtracting said mean value from a delayed signal output from one of said plurality of delay circuits, wherein said delayed signal has a delay time of one-half of a delay time obtained by a total of said plurality of said delay circuits;
a gain controller for amplifying the output of said subtraction means with a predetermined gain;
an adder for adding the output of said gain controller and said delayed signal input to said subtraction means;
a non-linear processing circuit to which the output of said adder and the maximum and minimum values output by said maximum and minimum detection circuits are input, said non-linear processing circuit outputting the maximum value if the output signal of said adder is larger than the maximum value, outputting the minimum value if the output signal of said adder is smaller than the minimum value, and outputting the output signal of said adder if the output signal of said adder is between the maximum value and the minimum value;
an output terminal for outputting the output of said non-linear processing circuit as a contour restored signal;
and
a contour amplitude detection circuit for detecting a difference between the maximum value and the minimum value detected by said maximum value detection circuit and minimum value detection circuit and controlling the gain of said gain controller according to said difference detected.

9 more elements

A contour restoration apparatus comprising:

an input terminal for video signals;
a plurality of delay circuits connected in series to said input terminal, each of said plurality of delay circuits having a predetermined delay time for a signal input thereto;
a maximum value detection circuit for detecting a maximum value among an input video signal and output signals of said plurality of delay circuits;
a minimum value detection circuit for detecting a minimum value among signals same as those input to said maximum value detection circuit;
a mean value circuit for calculating a mean value of output signals of said maximum and minimum value detection circuits;
a subtraction means for subtracting said mean value from a delayed signal output from one of said plurality of delay circuits, wherein said delayed signal has a delay time of one-half of a delay time obtained by a total of said plurality of said delay circuits;
a gain controller for amplifying the output of said subtraction means with a predetermined gain;
an adder for adding the output of said gain controller and said delayed signal input to said subtraction means;
a non-linear processing circuit to which the output of said adder and the maximum and minimum values output by said maximum and minimum detection circuits are input, said non-linear processing circuit outputting the maximum value if the output signal of said adder is larger than the maximum value, outputting the minimum value if the output signal of said adder is smaller than the minimum value, and outputting the output signal of said adder if the output signal of said adder is between the maximum value and the minimum value;
an output terminal for outputting the output of said non-linear processing circuit as a contour restored signal;
a contour extraction circuit to which a signal located centrally among an input video signal and output signals of said plurality of delay circuits and signals locating before and after the signal are input, said contour extraction circuit comprising multipliers for multiplying each of three signals input thereto with a predetermined coefficient and an adder for adding the three multiplied signals;
another gain controller for amplifying the output of said contour extraction circuit with a predetermined gain;
another adder for adding the output of said another gain controller and the centrally located signal;
a contour amplitude circuit for detecting a difference between the maximum value and the minimum value detected by said maximum value detection circuit and minimum value detection circuit and for outputting a coefficient determined according to the difference detected;
and
a mixer for mixing the output (1) of said non-linear processing circuit and the output (r) of said another adder according to an equation
kn.times.1+(1-kn).times.r
wherein kn is a coefficient given by said contour amplitude detection circuit.

15 more elements

Dependencies are inferred from the claim text.

Contour restoration apparatus

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Contour restoration apparatus

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Abstract

Claims5