A New Thresholding Technique for Despeckling of Medical Ultrasound Images

Ultrasound imaging is the most commonly used imaging system in the medical field. Due to various sources of interferences medical images are often deteriorated by noise. Main problem to this imaging technique is introduction of speckle noise. Speckle noise is a mottling of the image with dark and bright spots, which degrades the fine details and quality of image. The primary objective of this paper is to implement a multi-resolution based method for despeckling of ultrasound images and compare it with existing state-of-art techniques. There have been several methods for efficient reduction of speckle noise present in ultrasound images in order to reduce the noise level and improve the visual quality for better diagnoses. In this paper an improved method is given which can determine an optimal threshold and neighbouring window size for every subband by the Stein´s unbiased risk estimate (SURE). Experiments demonstrate that the proposed method achieves better results than some of the best adaptive and non-adaptive despeckling techniques. The proposed method can also be extended to the dual-tree complex wavelet transform (DT-CWT).