Wavelet-based homomorphic De-speckling technique with directional weighted-averaging stage

الملخص EN

In this paper, a new homomorphic wavelet-based de-speckling technique is proposed.

The technique combines a spatial domain processing with another transform domain processing in a homomorphic environment.

The spatial domain nonlinear processing is based on replacing each log-transformed pixel value of the speckled image by a weighted-average of the logtransformed pixel values in the neighborhood of that pixel.

The weighted averaged logtransformed image is then subjected to wavelet thresholding for further nonlinear transform domain processing.

An exponential operation on the filtered output is used to simulate the final homomorphic antilog-transformation stage and to obtain the de-speckled image.

Quantitative and qualitative measures prove the superiority of the proposed technique for the applications of image classification and recognition in ultrasonic and SAR systems.