PRACTICAL ISSUES ON INVARIANT IMAGE AVERAGING USING THE BISPECTRUM

In this work we present experimental results on the use of the Bispect rum for translational invariant image averaging. The main issue is to systematically explore the applicability of Bispectral averaging to pr actical cases where the starting images are rather noisy. The main con clusion is that this type of averaging process presents a number of in trinsic instabilities that makes the whole approach difficult to use. We start by proving that the sum of two Bispectra is not necessarily a Bispectrum. We then present a number of practical studies on how many Bispectra from noisy realizations of a given image are needed for a m eaningful image recovery as a function of the image signal-to-noise ra tio. The question of averaging a non-homogeneous data set is also addr essed. Some practical instabilities associated with recursive recovery methods are discussed, as well as some practical clues to overcome th em.