The invention concerns a method which consists in processing in a central unit (4) the digitized image (1) obtained by sensing noisy radiation. The image (1) is considered as a table of pixel intensity values, which is broken down into p elementary tables of n pixels so as to subsequently order them into a processing table with p lines of n columns; applying to said table a factorial analysis method, to deduce therefrom the n significant factors; then reconstituting a reconstructed processing table taking into account the most significant factors, and in deducing therefrom a reconstituted image wherein the high-frequency noise is reduced, maintaining a satisfactory contrast.