Active Shape Model-Based Segmentation of Digital X-ray Images

We propose an improved search procedure for Active Shape Model (ASM) based delineation of anatomical structures in digital X-ray images. Whereas the original ASM search method [1] iteratively improves the current estimate of the location of boundary points by a limited least squares adjustment of the pose and shape parameters, our method additionally requires the subsequent changes in shape during the search to be smooth, which is achieved by using a minimum cost path search algorithm. We compare the two methods on a database of more than 400 manual segmentations of digital X-ray images of the femur, humerus and calcaneus. We evaluate the accuracy and robustness of both methods using a cross-validation procedure.