Method and apparatus for performing motion compensated temporal filtering in video encoding

摘要

A method (50) and apparatus (40) for reducing noise in a video signal calculates (53) a discrimination value of a filter based on a magnitude difference between a current frame and a prior frame of a sequence of frames and modifies (54) the current frame using the modified discrimination value. The output of the filter is calculated as follows: g(i, j, k)=f(i, j, k)±beta wherein: f (i, j, k) is the current frame input to the filter; g(i, j, k) is the current frame output from the filter; and beta is the discrimination value of the filter, which is calculated as follows: $\mathrm{beta}=\{\begin{array}{ccc}{\mathrm{kappadelta}}^{\text{'}}+\mathrm{chi},& {\mathrm{delta}}^{\text{'}}=\max \left\{\mathrm{delta},{\mathrm{delta}}_0\right\},& \mathrm{delta}<{\mathrm{delta}}_1\\ 0,& & \mathrm{delta}>={\mathrm{delta}}_1\end{array}$ in which: kappa and chi are constants less than one; delta is a magnitude difference between the current frame and the prior frame; and delta0 and delta1 are constants that satisfy delta0<=delta1.