Comprehensive Survey on SAR Image Despeckling Techniques

Synthetic Aperture Radar (SAR) is a satellite imaging technology which produce high resolution images and can be used in varied atmospheric conditions. SAR obtains higher resolution remote sensing images from broad areas of terrain. It can be used day and night under all weather conditions. Unwanted data which affects the actual details of the image is called as noise. Inherent property of SAR is Speckle Noise of multiplicative nature which degrades SAR image quality. The backscattered echoes from objects undergo interference constructively and destructively which results in speckled image. The process of removing speckle noise is called as despeckling. The essential feature of despeckling technique is to effectively filter homogeneous areas while preserving textures and edges. The literature on despeckling methods for SAR images in both spatial and transform domain has been reviewed in this paper in chronological order.