Digital video formatting scheme for analog format video signals using adaptive filtering
AssigneeSiGear Europe Sarl
InventorsFriederich Mombers, Alain-Serge Porret, Melly Thierry
Life of this patent
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Abstract
A digital video formatting system operates to format an analog format video signal to within a desired amplitude range using an adaptive filtering scheme which implements flat gain scaling, frequency-dependent gain scaling and adaptive offset correction. The adaptive filtering scheme selects a frequency-independent flat gain scaling mode or a frequency-dependent gain scaling mode based on the characteristics of the active video signal. The filtered video signal is fed back to an adaptive weight computation block to update the offset correction value, the filter coefficients and the mode selection signal.
Claims20
A digital video formatting system for a television signal receiver configured to receive an input digitized analog format video signal and to generate an output digitized analog format video signal, the digital video formatting system comprising:
- an offset correction circuit configured to receive the input digitized analog format video signal being an active video signal and to introduce an offset correction value to the input digitized analog format video signal to generate an offset corrected analog video signal;
- an adaptive filter configured to receive the offset corrected analog video signal, the adaptive filter operative to filter the offset corrected analog video signal to within a predetermined amplitude range based one or more filter coefficients and based on a selected operation mode, the adaptive filter configured to generate a filtered analog video signal, the filtered analog video signal being used to generate the output digitized analog format video signal;
- and
- an adaptive weight computation block configured to receive the filtered analog video signal and to generate, based on characteristics of the filtered analog video signal, the offset correction value, the one or more filter coefficients and a mode selection signal selecting one of two operation modes,
- wherein the adaptive filter operates in a first operation mode to apply the one or more filter coefficients to scale an amplitude of the offset corrected analog video signal independent of signal frequency, and the adaptive filter further operates in a second operation mode to apply the one or more filter coefficients to scale the amplitude of the offset corrected analog video signal as a function of signal frequency.
A method in a television receiver to format an input digitized analog format video signal and to generate an output digitized analog format video signal, the method comprising:
- receiving the input digitized analog format video signal being an active video signal;
- introducing an offset correction value to the input digitized analog format video signal to generate an offset corrected analog video signal;
- filtering the offset corrected analog video signal to within a predetermined amplitude range based on one or more filter coefficients and based on a selected operation mode to generate a filtered analog video signal;
- generating the output digitized analog format video signal indicative of the filtered analog video signal;
- and
- generating based on characteristics of the filtered analog video signal the offset correction value, the one or more filter coefficients and a mode selection signal selecting one of two operation modes,
- wherein filtering the offset corrected analog video signal comprises:
- applying the one or more filter coefficients to scale an amplitude of the offset corrected analog video signal independent of signal frequency in a first operation mode;
- and
- applying the one or more filter coefficients to scale the amplitude of the offset corrected analog video signal as a function of signal frequency in a second operation mode.
Dependencies are inferred from the claim text.