Adaptive Non-local means filtering for speckle noise reduction

The aim of this study is to present the results of investigations concerning the evaluation of non-local means filter for multiplicative noise removal in ultrasonographic images. In this work a comparison of different techniques based on the concept of the non-local means filtering and a novel application for a filter called trimmed non-local means has been presented. The proposed modification is a generalization of the non-local means algorithm, in which the pixels are ordered using rankordered absolute differences statistic and only the most centrally located pixels in the filtering window are considered and used to calculate the weights needed for the averaging operation. The experiments confirmed that the proposed algorithm achieves comparable results with the existing state-of-the-art denoising schemes in suppressing multiplicative noise in ultrasound images.