Pattern recognition in sar images using f ractional r andom f ields and its possible application to the problem of the detection of oil spills in open sea

Abstract

In this article we present a short proof of a duality principle concerning frame and Riesz sequences due to Ulanovskii and Olevskii. Our proof is derived from a result on compression on orthogonal projections. As a consequence, we get a better lower frame (Riesz) bound for the sequences than the one deduced from the original proof.