Generating a hierarchical aspect graph based on multiple range data

Abstract

AbstractThis paper proposes a method of producing an aspect graph from multiple range data. Generally, when an object is of complex shape, the search of its shape and posture become more difficult, since the number of aspects necessarily increases. To solve this problem, a hierarchical aspect graph (an expanded idea of the aspect graph) is introduced. After a projection range image has been divided into regions based on its differential geometrical features, the viewpoint space is also divided referring to the difference of topologies on the zero‐crossing surface of a scale space. Hierarchical events by which a viewpoint space is divided are obtained by analyzing changes of the topology of the differential geometrical features caused by a viewpoint and resolution at feature points. A reliable aspect graph is produced by interpolating unobserved events due to the limited data of viewpoints and resolutions. The viewpoint space is divided coarsely in its upper structure, and densely in its lower structure. This makes an efficient search of the shape, position and posture of an object based on the coarse‐to‐fine tactic. Three‐dimensional aspect graphs based on real range‐finder input data were processed. The results show the usefulness of the proposed method for identifying the shapes, positions and postures of objects and analyzing moving images.