Contour Extraction of Overlapped Objects

—Refinement of Pairing Vertices and Generating Contours—

Abstract

We perceive a contour on the boundary of the regions with the different properties. However, we can also perceive the contour when there is no such physical difference. We call such a contour a subjective contour. Some researches proposed the methods of generating inner contours of overlapping objects using the model for generating a subjective contour. In this study, we try to improve the degree of allowable overlapping by using the energy minimization and the combinatorial optimization. In the pairing process, we defined an energy terms based on the properties in which an object forms convex closure and its contour is smooth. The system selects the optimal pairs of vertices by the combinatorial optimization based on the energy function composed with the energy terms. We conducted experiments on images of leaves and show the proposed method can generate inner contours of overlapping objects with one or both ends hidden or in which the background can be seen, for which the conventional method can't easily generate inner contours.