A Modified Non Local-based Speckle Filtering in Ultrasound Images

Speckle degrades the quality of ultrasound images, which limits the accuracy in clinical diagnose. Recently, a newly developed filter, namely Non-Local Means (NL-means), works well in image denoising. Since the NL-means filter is originally designed for Gaussian noise removal, it cannot be directly applied to ultrasound image despeckling with Rayleigh distribution noise. In this paper, we propose a modified Non Local-based (MNL) filter to adapt for speckle reduction. Experiments were carried out on synthetic data and real ultrasound images with this proposed method, the conventional NL-means and Maximum Likelihood filters. Comparison results show that our method is capable of effectively reducing speckle noise while well preserving tissue boundaries for ultrasound images.