Patent ID: 7418149
Filing Date: 2008-08-26
Classification: G06K,G06T,H04N

Abstract:
1. An apparatus for reducing multiple noise types in a video input signal, said apparatus comprising: a noise power converter for receiving and using said video input signal, a variance of additive noise, a variance of multiplicative noise and an indication of a type of noise for estimating an equivalent additive noise variance signal; a temporal recursive filter using said equivalent additive noise variance and said video input signal for generating a temporally filtered video signal and a residual noise variance signal; a spatial noise reducer using said residual noise variance signal and said temporally filtered video signal for spatially filtering said video input signal to provide a video output signal having reduced noise; and wherein said noise power converter comprises a low pass filter for filtering said video input signal to provide a low pass filtered signal; a shape adaptive window for receiving and using said low pass filtered signal, and a given threshold tolerance for calculating a binary signal ωij(c,r) representing local classification results within said threshold tolerance and a signal N(c,r) indicative of similar pixels in said window; a shape adaptive window mean estimator using said binary signal ωij(c,r), said N(c,r) signal and said video input signal for calculating a local estimated means signal value μY(c,r) given by and an equivalent additive noise variance calculator using said local estimated means signal value μY(c,r), said variance of additive noise, said variance of multiplicative noise and said indication of a type of noise for calculating said equivalent additive noise variance signal.