Contour completion of partly occluded objects for more natural raster-vector conversion

This paper proposes a system for completing the contour of an object which is partly occluded by other objects. The proposed system classifies objects into rotational symmetry objects, line symmetry objects and the other objects. To a rotational symmetry object, the system estimates the angle and center of rotation of the object focusing on the periodicity of the curvature change of the contour. Rotating the object with the estimated angle and center of rotation, the system reconstructs the occluded part of the contour. To a line symmetry object, the system detects line symmetry axes. The occluded part is completed by folding the shape to the line symmetry axes. To other shapes, the system uses a spline interpolation to complete the contour. We have experimentally confirmed the effectiveness and limitations of the proposed method by comparing the proposed method with human perception.