Nonlinear Wavelet Processing for Enhancement of Images
Jan Erik Odegard, Markus Lang, Haitao Guo, Ramesh A. Gopinath, C.S. Burrus · 1994
In this note we address some recent results on nonlinear wavelet processing. In particular we illustrate how the soft thresholding algorithm due to Donoho [2] can successfully be used to remove speckle in SAR imagery. Furthermore, more surprisingly we also show that transform coding artifacts, such as blocking in the JPEG algorithm, can be removed to achieve a perceptually improved image by post processing the decompressed image. Contact Address: Jan Erik Odegard Electrical and Computer Engineering - MS 366 Rice University, Houston, TX-77251-1892 Phone: (713) 527-8101 x3508 FAX: (713) 524-5237 email: [email protected] 1 Introduction We consider the problem of noise reduction by nonlinear wavelet processing. In particular we focus on two applications of the recently developed theory related to wavelet (soft) thresholding [2]. The model for the problems we consider is as follows. Let y = x + e be the observed image of the ideal image x corrupted by some noise e. Most observed images t...