<title>Part description and segmentation using contour, surface, and volumetric primitives</title>

In this paper we discuss the ongoing research on the problem of shape description, and decomposition of complex objects in range images. We propose a paradigm for part description and segmentation by integration of contour, surface, and volumetric primitives. Unlike previous approaches, we use geometric properties derived from both bpundary-based (surface contours and occluding contours), and primitive-based (biquadratc patches and superquadric models) representations to define and recover part-whole relationships, without a priori knowledge about the objects or the object domain. The descriptions thus obtained are independent of position, orientation, scale, domain and domain properties, and are based purely on geometric considerations. We pose the problem of integration in terms of evaluation of the intermediate descriptions and segmentation of the objects in a closed loop process. We present algorithms for superquadric edge detection and apparent contour generation. The criteria for the evaluation of the superquadric models is discussed and examples of real objects supporting our approach are presented.