Subjective and objective evaluations of feature selected multi output filter for speckle reduction on ultrasound images

Abstract

Ultrasonographic examination, either as visual inspection or quantitative analysis, is the most widely diagnostic resource. However, speckle noise is one of the drawbacks that makes it less effective than other medical imaging systems. Several speckle reduction methods often offer effective speckle reduction but generally suffer from oversmoothing, a blurring effect and a man-made appearance. In this paper, we propose a multi-output filter based on the multiplicative multiresolution decomposition (MOF-MMD). This multi-scale based method enables the enhancement of the original image and provides three enhanced outputs: global, edge and texture images. The multi-output filter aims at offering an enhanced image according to the features desired by radiologists. The different structures, textures and edges are filtered according to the contour image obtained by morphological operators. Three radiologists with different years of experience, have subjectively evaluated the speckle reduction methods according to enhanced features. The results of objective metrics and subjective evaluation showed that the proposed method reduces speckle and could help radiologists, according to their years of experience, in the diagnostic task. Finally, the correlation between three objective metrics and the perceived quality of contrast, diagnostic, texture and edges show that an objective metric is suitable for assessing quality of ultrasound images.