Speckle Reduction and Contrast Enhancement of Echocardiograms via Multiscale Nonlinear Processing

Abstract— This paper presents an algorithm for speckle reduction and contrast enhancement of echocardiographic images. Within a framework of multiscale wavelet analysis, we apply wavelet shrinkage techniques to eliminate noise while preserving the sharpness of salient features. In addition, nonlinear processing of feature energy is carried out to enhance contrast within local structures and along object boundaries. We show that the algorithm is capable of not only reducing speckle, but also enhancing features of diagnostic importance, such as myocardial walls in two-dimensional echocardiograms obtained from the parasternal short-axis view. Shrinkage of wavelet coefficients via soft thresholding within finer levels of scale is carried out on coefficients of logarithmically transformed echocardiograms. Enhancement of echocardiographic features is accomplished via nonlinear stretching followed by hard thresholding of wavelet coefficients within selected (midrange) spatial-frequency ...

• Type: Journal
• Year: 1998
• Where: TMI
• Authors: Xuli Zong, Andrew Laine, Edward A. Geiser
• Keywords: Enhancement, Speckle Reduction, TMI 1998, Wavelet