Quantitative and Qualitative Measures for the Evaluation of the Superquadric Models

In this paper we discuss the evaluation criteria for superquadric models recovered from the range data. We present arguments to support our belief that both quantitative and qualitative measures are required in order to evaluate a superquadric fit. The concept of superquadric contraction and dilation is introduced and used to derive a novel interpretation of the modified superquadric inside-outside function in terms of contraction/ expansion factor. The same concept also gives a close initial guess for the numerical procedure computing the minimum Euclidean distance of a point from a superquadric model. The minimum Euclidean distance map is introduced as a qualitative criterion for interpretation of fit. View-dependent qualitative measures like the contour-difference map and the z-distance map are shown to be essential for the complete evaluation of the models. Analytical solution and techniques for the contour generator on superquadric models are presented. Finally, examples of real objects are given to generate the measures. Comments University of Pennsylvania Department of Computer and Information Science Technical Report No. MSCIS-89-49. This technical report is available at ScholarlyCommons: http://repository.upenn.edu/cis_reports/843 QUANTITATIVE and QUALITATIVE MEASURES for the EVALUATION of the SUPERQUADRIC MODELS Alok Gupta, Luca Bogoni, and Ruzena Bajcsy MS-CIS-89-49 GRASP LAB 188 Department of Computer and Information Science School of Engineering and Applied Science University of Pennsylvania Philadelphia, PA 19 104