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Effective Speckle Noise Removal of SAR Image Based on Combination of Modified PCA and HMF with Enhancement

Despeckle of Sythetic Aperture Radar (SAR) image is a challenging task for the reseachers due to the presence of multiplicative speckle noise caused by scattered radar waves. This multiplicative speckle noise creates echoes that are directly degrades image quality, aslo makes the object identification difficult. From past few decades the number of speckles noise reduction techniques have been developed to restore the perception quality of SAR images, so that the resulting images are well suitable for further undertaking. However, the existing techniques are not able to perserve edge details of the image while reducing speckle noise. The system model proposed in this paper consists of three stages to reduce the speckle noise in the SAR image. The first stage of the proposed model consists of two stage block based modified Principal Componet Analysis (PCA) which removes maximum amount of speckle noise in SAR image. This block based modified PCA is obtain by selecting different values of standard deviation by applying certain technique that can reduce the maximum amount of speckle noise present in the SAR image. The second stage of proposed model consists of Hybrid Median Filter (HMF) that is used to further removal of the multiplicative noise remaining in the modified PCA output image, particulaly to remove the speckle noise at the edges. Final stage is used to enhance the features of the despeckle image using sharpening filter. In order to maintain good image perception quality, in this paper the selection of the standard deviation is an important factor in the proposed system model to effictively reduce the speckle noise with the existing methods. Thus the system method used in this paper produced better experimetal results than existing methods with regarding to both removal of speckle noise with enhancement of image features.