Active contour model using a priori knowledge of region shape

To improve the region extraction accuracy in active contour model (ACM), we propose a novel method for employing the a priori knowledge of a target region shape. The proposed method is based on an idea that a user-drawn initial contour for ACM can include the shape features of a target region. In this method, the sequence of shape features (e.g., corner, line, and curve) is obtained from an initial contour, and this sequence is used as the a priori knowledge of a target region. During region extraction procedure, by finding the optimal assignment of the shape features to contour control points and determining the optimal positions for these points, ACM energy is minimized and the knowledge is reflected on an extracted region shape. Using an initial contour not only as an initial value for the energy minimization but also as the a priori knowledge of a target region shape, the proposed method can employ the a priori knowledge effectively without time-consuming preparation work.