Algorithm for Speckle Lessening and Image Improvement in SAR Images Using Wavelet Transforms

DOI

No DOI

Published In

Volume 2, Issue 6 (2021)

Published Online

November-December 2021

Pages

01-03

Article Type

Research Article

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Abstract: The speckle reduces detectability of image features. It is essential to remove speckle for proper identification of features and image analysis. Any feature in ribbon like shape like roads runways or edge features require speckle removal for analysis. The effect of speckle can be reduced in two methods. First, in the processing of image during image formation and second using image filtering techniques. The second method suppresses speckle noise using filters like a Lee filter, Kuan/ Nathan filter, etc. In speckled radar images, filtering must achieve a tradeoff between smoothing of homogeneous area and edge and texture preservation. In this work processing has been carried out in wavelet domain. Donoho and Johnstone pioneered the theoretical formalization of filtering additive i.i.d. Gaussian noise (of zero mean and standard deviations) via thresholding wavelet coefficients. A wavelet coefficient is compared to a given threshold and is set to zero if its magnitude is less than the threshold; otherwise, it is kept or modified (depending upon the thresholding rule).