Minimum Entropy Autofocus Correction of Range-Varying Phase Errors in ISAR Imagery

Abstract

In this article, we present an ISAR autofocus algorithm that compensates for range-varying phase errors which can degrade ISAR imagery formed with an unknown rotation rate. Our algorithm is non-parametric and is capable of dealing with a non-constant rotation rate. The algorithm described is based on optimizing image focus by minimizing the image entropy.