New Adaptive PolSAR Speckle Filtering Based on Sigma Edge Detection

Radar imaging encounters a significant hurdle with the presence of noise, commonly referred to as speckle. This noise complicates the interpretation of images by diminishing the accuracy of the conveyed information. To address the speckle effect and enhance image quality, filtering becomes essential. In this paper, we introduce a novel polarimetric filtering approach that integrates edge detection with the improved sigma filter. This integration aims to enhance the effectiveness of the method in reducing speckle noise while retaining crucial information. This approach relies on calculating the probability density of the radar signal to determine a confidence interval for pixels exhibiting similar characteristics in a homogeneous region while safeguarding heterogeneous areas. This will conserve not only the edges but also the polarimetric information. The newly applied method enables filtering elements within the polarimetric covariance or coherency matrix. To assess the effectiveness of the filtering process, we employed the following criteria: smoothing homogeneous regions, preserving edges, and retaining polarimetric information.