Spatio-temporal filtering method for noise reduction during pre-processing of picture sequences in video encoders

摘要

A method of filtering noise of digital pictures comprises selecting a first set of pixels (WORKING_WINDOW) constituted by the union of a pixel of the current picture to be filtered (P) and of a second set of pixels temporally and spatially near (PIXEL_NEAR) to said pixel, calculating a certain number (N) of extended sums (SUMk_j) of values assumed by as many pre-established weight functions of the intensity of a selected video component (k_j) on the first set of pixels (WORKING_WINDOW). The pixels of the second set of pixels near (PIXEL_NEAR) can belong to the current picture or to a preceding picture.;Several noise filters for digital pictures implementing the method of the invention are also presented.