Contour let-BasedMethod for Speckle Reduction with Adaptive Estimation of Noise Level | ||
| Al-Rafidain Engineering Journal (AREJ) | ||
| Article 15, Volume 22, Issue 5, December 2014, Pages 197-211 PDF (0 K) | ||
| DOI: 10.33899/rengj.2014.101017 | ||
| Authors | ||
| Jassim M. Abdul-Jabbar; Amenah. I. Kanaan; Zena N. Abdulkader | ||
| Abstract | ||
| Synthetic aperture radar (SAR) and ultrasonic images are inherently affected by speckle noise, which is caused by the coherent nature of the scattering phenomena. This paper presents a contourlet-based method for speckle reduction with an adaptive method for noise-threshold level estimation in a homomorphic framework. The method starts with the generation of many random images simulating the standard deviation level of the log-transformed speckled image. Different contourlet threshold levels are then calculated based on such simulations. Different contourlet coefficients of speckled images are thresholded by their corresponding pre-calculated contourlet thresholds.An exponential operation on the reconstructed output after thresholding is used to simulate the final homomorphic antilog-transformation stage and to obtain the de-speckled images. Unlike other classical and recent de-speckling methods, the despekled images indicate clearly the superiority of the proposed method for speckle reduction, especially for SAR images which possess a lot of detailed textures. | ||
| Keywords | ||
| Speckled Images; Contourlet Transform; Homomorphic Framework; Adaptive thresholding | ||
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