Inter-dimensional chrominance noise reduction system

Claim 3

The control method set forth in claim 1 comprising 1 the further steps of: detecting occurrence of picture changes on a field by field basis and inhibiting said noise reduction when said changes are detected.

Claim 4

The control method set forth in claim 1 wherein said step of detecting spatial picture characteristics in said path comprises the step of detecting horizontal picture transitions.

Claim 5

The control method set forth in claim 1 wherein said step of detecting spatial picture characteristics in said path comprises the step of detecting vertical picture transitions.

Claim 6

The control method set forth in claim 1 wherein said step of detecting spatial picture characteristics in said path comprises the steps of detecting horizontal picture transitions and detecting vertical picture transitions.

Claim 7

The control method set forth in claim 1 wherein the step of detecting spatial picture characteristics in said path comprises the step of detecting chroma level.

Claim 8

The control method set forth in claim 1 wherein the step of detecting spatial picture characteristics in said path comprises the step of detecting luminance level.

Claim 11

The method set forth in claim 8 wherein said detecting step comprises detecting the outline of a stationary object in said picture signal.

Claim 12

The method set forth in claim 8 wherein said detecting step comprises detecting the outline of a moving object in said picture signal.

Claim 15

The method set forth in claim 11 wherein said step for generating Vout is carried out digitally and comprises the further steps of sampling and converting said incoming chrominance component Vin to digital values, and converting said resultant digital Vout function to analog values in real time.

Claim 16

The method set forth in claim 12 wherein said sampling step is carried out at a sampling rate which is at least twice the demodulated bandwidth of said chrominance component.

Claim 19

The time domain chroma noise reduction method set forth in claim 14 further comprising the step of noise reduction in the horizontal spatial domain.

Claim 20

The time domain chroma noise reduction method set forth in claim 14 further comprising the step of noise reduction in the vertical spatial domain.

Claim 21

Apparatus for generating a chroma difference signal for controlling operation of a time domain chrominance noise reduction system operating upon a chrominance component of a quadrature modulated color television signal, said apparatus comprising: a chroma input for receiving an incoming demodulated chroma component, a summing junction having a first input connected to said chroma input and having an output, processor means connected to said output of said summing junction for generating a Vout function in accordance with the following expression: where Vin equals the incoming chrominance component, Fl equals a field interval, and 1/2H equals one half of a line interval of said color television signal, a difference junction connected to said output of said summing junction and to subtract therefrom said Vout function from said processor to yield a difference value, coefficient of recirculation amplifier means connected to said difference junction for amplifying said difference value in accordance with a predetermined coefficient of recirculation to yield a recirculation value, logic generator means connected to receive said color television signal to determine picture conditions therein and to generate a logic signal in accordance therewith, linear multiplier means connected to multiply said recirculation value by said logic signal, to yield a demodulated chroma difference signal, the output of said multiplier means being connected as a second input to said summing junction to recirculate said demodulated chroma difference signal with said incoming chroma component.

Claim 22

Apparatus for generating a chroma difference signal for controlling operation of a time domain chrominance noise reduction system operating upon a chrominance component of a quadrature modulated color television signal, said apparatus comprising: a chroma input for receiving an incoming demodulated chroma component, a summing junction having a first input connected to said chroma input and having an output, processor means connected to said output of said summing junction for generating a Vout function in accordance with the following expression: where Vin equals the incoming chrominance component, Fl equals a field interval, and 1/2H equals one half of a line interval of said color television signal, a difference junction connected to said output of said summing junction and to subtract therefrom said Vout function from said processor to yield a difference value, coefficient of recirculation amplifier means connected to said difference junction for amplifying said difference value in accordance with a predetermined coefficient of recirculation to yield a recirculation value, logic generator means connected to receive said color television signal to determine picture conditions therein and to generate a logic signal in accordance therewith, linear multiplier means connected to multiply said recirculation value by said logic signal, to yield a demodulated chroma difference signal, the output of said multiplier means being connected as a second input to said summing junction to recirculate said demodulated chroma difference signal with said incoming chroma component.

Claim 23

The apparatus as set forth in claim 17 wherein said logic generator means comprises: input means for receiving said quadrature modulated color television picture signal; chroma level detection means connected to said input means for detecting the presence of a chroma component in said color televison picture signal, and for putting out a first control value whenever chroma level is above a predetermined minimum chrominance level, black level detection means connected to said input means for detecting that luminance level is below a predetermined minimum luminance level and for putting out a second control value whenever luminance is below said minimum luminance level.

Claim 24

i9. The apparatus set forth in claim 18 further comprising larger input gate means having one input connected to receive said first control value and having a second input connected to receive said second control value, and for putting out as a first control signal the larger one of said two input values.

Claim 25

The apparatus set forth in claim 18 further comprising black level inhibit means for inhibiting said second control value during horizontal transitions detected by said inhibit means in a luminance component of said color television picture signal.

Claim 26

The apparatus set forth in claim 18 further comprising chroma level detection inhibit means for inibiting said first control value whenever chroma is not present in said color television picture signal above a minimum chroma level, and whenever a luminance horizontal transition component is present in said color television picture signal.

Claim 27

2 2. The apparatus set forth in claim 21 further comprising override means responsive to said chroma level detection means and being connected for overriding said chroma level detection inhibit means whenever chroma is present in said color television picture signal above a predetermined chrominance value.

Claim 28

The apparatus set forth in claim 19 further comprising control path means connected to said difference junction and responsive to said difference value to yield a processed difference value and further comprising second larger input gate means having one input connected to receive said processed difference value and having a second input connected to said first larger input gate means to receive said first control signal, and for putting out as a second control signal the larger one of said two input values.