Abstract: In this paper, we describe an acceleration technique for the semi-automatic image segmentation algorithm, "intelligent scissors." Using intelligent scissors, the user can accurately and interactively extract an object from a digitzed image. However, the original algorithm suffers from slow performance when large images are trated. In practice, pixels within the non-edge regions are seldom involved in the determination of boundaries (segmentation curves). If these pixels are removed before boundary determination, the performance of intelligent scissors can be improved. We generate a slimmed graph to achieve this goal with significant improvement in response time.