Speckle Noise Reduction in Ultrasound Images- A Review

Ultrasound imaging is a widely used and safe medical diagnostic technique, due to its non-invasive nature, low cost and capability of forming real time imaging. Ultrasound imaging uses high-frequency sound to image internal structures by differing reflection signals produced when a beam of sound is projected into the body and bounces back at interfaces between the structures. However the usefulness of ultrasound imaging is degraded by the presence of signal dependant noise known as speckle. The speckle pattern depends on the structure of the image tissue and various imaging parameters. Speckle noise present in ultrasound image affects edges and fine details which limit the contrast resolution and make diagnostic more difficult. There are two main purposes for speckle reduction in medical ultrasound imaging (1) to improve the human interpretation of ultrasound images (2) despeckling is the preprocessing step for many ultrasound image processing tasks such as segmentation and registration. A number of methods have been proposed for speckle reduction in ultrasound imaging. The objective of this paper is to give an overview of speckle reduction in ultrasound imaging Keywords—Ultrasound image, Speckle noise, despeckling, kidney, filters.