Title: Site Model Acquisition under the UMass RADIUS Project Authors: Robert T. Collins, Allen R. Hanson, and Edward M. Riseman Affiliation: Computer Vision Research Laboratory, Dept. of Computer Science, University of Massachusetts, Box4610, Amherst, MA. 0l003-4610 Abstract: A set of image understanding (IU) modules is being developed for performing several geometric site modeling tasks, including initial model acquisition, model extension, model-to-image registration and site model refinement. This paper describes how the UMass system would acquire an initial site model. IU algorithms have been developed to hypothesize potential building roofs in an image, automatically locate supporting geometric evidence in other images, and determine the precise shape and position of the new buildings via multi-image triangulation. This process is demonstrated on a subset of images from the RADIUS Model Board 1 data set. Keywords: RADIUS, model acquisition, aerial image understanding