1. A process for converting into progressive format digital images organized in half-frames or fields with interlaced lines or rows, comprising the operations of: selecting a set of successive lines of one of said fields; and reconstructing by pixels an image line set between the successive lines of said set, the successive lines of said set defining a work window, said reconstruction operation comprising the steps of: creating a set of candidate patterns associated to said work window by selecting the candidate patterns to be considered within said work window; applying to the candidate patterns of said set of candidate patterns a first cost function which is representative of the correlations between pairs of pixels; applying to the candidate patterns of said set of candidate patterns a second cost function which is representative of the non-correlations between pairs of pixels; selecting, for each candidate pattern, respective internal correlations and external non-correlations, calculating corresponding scores for said candidate patterns using said first cost function; selecting a best pattern by comparing the corresponding scores of the candidate patterns with a threshold; and selecting the pixels of said work window identified by the best pattern selected, reconstructing said image line by filtration starting from said pixels.