Ultrasound speckle reduction and edge enhancing in Laplacian pyramid

Abstract

A new method which reduce speckle noise and enhance contrast is proposed for medical ultrasound imaging. We modified the conventional nonlinear coherent diffusion (NCD) and proposed the edge enhancing nonlinear coherent diffusion (EENCD) for this purpose. The EENCD suppresses the speckle noise in a homogenous region, and it performs both directional filtering on the contour direction and edge enhancement on the tangential direction in a structural region. The EENCD is embodied in the Laplacian pyramid. An image is decomposed into a Laplacian pyramid, and then, the EENCD filtering is done during reconstructing the Gaussian layer images, to produce the filtered image. The proposed method was compared with the conventional CED and NCD methods on the real ultrasound images. It has been shown that the proposed method can enhance the edges and the contrast is enhanced more than the conventional methods.