A system for segmenting ultrasound images

Segmentation of ultrasound images is difficult due to the existence of speckle noise. Erroneous edges from speckle noise are not only abundant but also have large magnitude due to the multiplicative nature of speckle noise. Moreover, boundary edges are usually incomplete, being missing or weak at some places. We propose a system to address these problems in two steps. First, based on the observation that boundaries in ultrasound images have the appearance of straight or gently curving line segments, we adopt Sha´ahsua and Ullman´s (1988) saliency map method to reduce speckle noise and enhance edges. Then we use a new snake model, which we call a systolic snake, to perform a multi-level feature search. The systolic snake can not only overcome local minima, but also effectively use both strong and weak image information. Furthermore, the system can be used in an automatic system since, unlike other snake models, ours does not need a close initialization The resulting system is tested on some ultrasound loin images and results are promising