Graph Matching Approach between Endoscope Images for Non-Rigid Motion using Blood Vessel Structure

It is important to estimate the size and shape of the polyp from endoscope images in the medical diagnosis. Ref.[1] was proposed as a method to estimate the absolute size of the polyp, where movement of endoscope in depth direction was estimated from two endoscope images. Ref.[1] introduced template matching using blood vessel to determine the correspondence between two images. However, it is not appropriate for actual endoscope environment since actual motion includes not only the camera transition but also the camera rotation. Further object motion is non-rigid motion and it is difficult to determine correct correspondence points between two images. So, this paper proposes a new approach to extract a blood vessel structure based on the blood vessel region using a graph structure, where the graph is matched between two images. Here, a matching method of blood vessels is described, where camera rotation and non-rigid motion of the target object are under consideration. Effectiveness of the proposed approach is confirmed in the experiments.