Speckle Noise Reduction in SAR Imagery Using a Local Adaptive Median Filter

Abstract

Speckle noise is the grainy salt-and-pepper pattern present in radar imagery caused by the interaction of out-of-phase waves with a target. A local adaptive median filter was developed that uses local statistics to detect SAR speckle noise and to replace it with a local median value. The performance of the local adaptive median filter was evaluated using RADARSAT and JERS-1 datasets based on both visual assessment and a number of numerical measures. In comparison with established filters, it was found that the local adaptive median filter outperformed others in achieving the best balance between speckle suppression and image detail preservation.