Application of a Fully Automatic Autofocusing Algorithm for Post-Processing of Synthetic Aperture Radar Images based on Image Entropy Minimization

  • A. Malamou National Technical University of Athens
  • A. Karakasiliotis National Technical University of Athens
  • E. Kallitsis National Technical University of Athens
  • G. Boultadakis National Technical University of Athens
  • P. Frangos National Technical University of Athens
Keywords: Autofocusing, post processing algorithm, synthetic aperture radar (SAR) imaging


In this paper an application of an autofocusing algorithm, previously developed by the authors for the case of Inverse Synthetic Aperture Radar (ISAR) [i.e. airborne radar targets], is presented here for the case of Synthetic Aperture Radar (SAR) geometry [i.e. ground radar targets]. Here, a new theory and methodology for generating SAR synthetic backscattered data is also developed. This algorithm is named ‘CPI-split-algorithm’, where CPI stands for ‘Coherent Processing Interval’. Moreover, two simulation scenarios are presented for a ship target, which is located on the sea surface. In the first simulation scenario, the ship is considered at first to be stationary, and subsequently an oscillatory movement is induced to its position along the vertical axis, due to sea surface motion. In the second simulation scenario, a partial loss of data is examined, caused by temporary accidental malfunctioning of radar transmitter or receiver, assuming that the target (ship) is stationary. Numerical results presented in this paper show the effectiveness of the proposed autofocusing algorithm for SAR image enhancement.