Range data processing: representation of surfaces by edges

Journal ArticleRepresentation of surfaces by edges is an important and integral part of a robust 3-D model based recognition scheme. Edges in a range image describe the intrinsic characteristics about the shape of the objects. In this paper we present three approaches for detecting edges in 3-D range data. The approaches are based on computing the gradient, thresholding, thinning and fitting straight lines or curves; fitting 3-D lines to a set of points, and detecting changes in the direction of unit normal vectors on the surface. These approaches are applied locally in a small neighborhood of a point. The neighbors of a 3-D point are found by using the k-d tree algorithm. As compared to previous work on range processing, the approaches presented here are applicable not only to sensor range data corresponding to any one view of the scene, but also to 3-D model data obtained using the Computer-Aided Geometric Design (CAGD) techniques, and to 3-D model built using the sensor data such as the data obtained by combining several views of an object. We present several examples where the data is synthetically genetrated, obtained from CAGD methods or obtained from a laser scanner. A comparison of the techniques is presnted

Children, Humanoid Robots and Caregivers

This paper presents developmental learning on a humanoid robot from human-robot interactions. We consider in particular teaching humanoids as children during the child's Separation and Individuation developmental phase (Mahler, 1979). Cognitive development during this phase is characterized both by the child's dependence on her mother for learning while becoming awareness of her own individuality, and by self-exploration of her physical surroundings. We propose a learning framework for a humanoid robot inspired on such cognitive development