Analysis of Denoising Techniques for Speckle Noise Removal in Synthetic Aperture Radar Images

Active Synthetic Aperture Radar (SAR) sensors use their own source of illumination to sense the earth surface. SAR sensors have the ability to penetrate through clouds and smoke like conditions, can operate on day and night, and have a sensitivity to each property in the microwave region. Generally, speckle is found in SAR images at the time of image acquisition and transmission. Speckle in the satellite image degrades image quality and makes it less informative about the target/features in the image under study. Denoising SAR image or speckle reduction is a great challenge for the researchers worldwide as classification or recognition becomes difficult on speckled SAR image. Thus it is of prior importance to reduce the speckle in the image before applying any image processing technique. So far many filtering techniques have been developed for denoising SAR images. The prime aim of denoising is to eliminate speckle noise by retaining the important feature of the images. Experimental results of applying different noise reduction techniques on ALOS PALSAR data has been demonstrated in the paper and investigations were performed on these techniques out of which Intensity Driven Adaptive Neighborhood (IDAN) and Median filter technique perform better smoothing than other methods.