ASM Driven Snakes in Rheumatoid Arthritis Assessment

Abstract

In this paper a method is proposed that combines active shape models (ASM) and active contours (snakes) in order to identify fine structured contours with high accuracy and stability. Based on an estimate of the contour position by an active shape model the accuracy of the landmarks and the contour in between is enhanced by applying an iterative active contour algorithm to a set of gray value profiles extracted orthogonally to the interpolation obtained by the ASM. The active shape model is trained with a set of training shapes, whereas the snake detects the contour with fewer constraints. This is of particular importance for the assessment of pathological changes of bones like erosive destructions caused by rheumatoid arthritis. © Springer-Verlag 2003.