Rapid world modeling: Fitting range data to geometric primitives

For the past seven years, Sandia National Laboratories has been active in the development of robotic systems to help remediate DOE`s waste sites and decommissioned facilities. Some of these facilities have high levels of radioactivity which prevent manual clean-up. Tele-operated and autonomous robotic systems have been envisioned as the only suitable means of removing the radioactive elements. World modeling is defined as the process of creating a numerical geometric model of a real world environment or workspace. This model is often used in robotics to plan robot motions which perform a task while avoiding obstacles. In many applications where the world model does not exist ahead of time, structured lighting, laser range finders, and even acoustical sensors have been used to create three dimensional maps of the environment. These maps consist of thousands of range points which are difficult to handle and interpret. This paper presents a least squares technique for fitting range data to planar and quadric surfaces, including cylinders and ellipsoids. Once fit to these primitive surfaces, the amount of data associated with a surface is greatly reduced up to three orders of magnitude, thus allowing for more rapid handling and analysis of world data

Efficient Free-Form Surface Modeling with Uncertainty

This paper describes the use of a previously developed surface model for representing 3D geometric information that is subject to uncertainty. The proposed model is based on a geometric data fusion technique that allows the efficient approximation of arbitrary triangular meshes in space with smooth surfaces. This paper shows how the shape modifiers defined in that model can be used to represent both global and local uncertainty associated with the input data. The possibility of handling scattered 3D points, taking into account their corresponding uncertainties, makes this technique a suitable tool for modeling free-form surfaces acquired through sensing, as well as for integrating 3D data obtained from multiple sensors with different associated confidences. 1 Introduction Free-form surface modeling is a field which can be applied to a wide variety of disciplines, including robotics, computer graphics, computer aided geometric design and geographic information systems. In mobile robot..