We report on a new system to augment a 3D block model of a real city obtained from aerial photogrammetry or aerial laser scanning with geo-referenced terrestrial data of the facades. The terrestrial images are acquired by a hand-held digital consumer camera. The relative orientation of the photographs is calculated automatically and fitted towards the 3D block model with minimized human input using vanishing points. The extraction of 3D primitives on the facades is based on line matching over multiple oriented images. The introduced city information system delivers a fully 3D geographic information data set and is called MetropoGIS.

We present a novel level of detail selection method for real-time rendering, that works on hierarchies of discrete and continuous representations. We integrate point rendered objects with polygonal geometry and demonstrate our approach in a terrain flyover application, where the digital elevation model is augmented with forests. The vegetation is rendered as continuous sequence of splats, which are organized in a hierarchy. Further we discuss enhancements to our basic method to improve its scalability.

Abstract This paper presents a method to automatically calculate texture maps for a given three‐dimensional object out of a sequence of images. It is used in our image‐based modeling approach after the registration of the images and the geometric modeling is done. We show that the presented method uses the information from all images by implicitly applying a weighting function. Using this approach the consideration of modeled occlusions as well as the detection and removal of non‐modeled occlusions is accomplished. The final resolution of the texture maps can be adjusted on a pixel/cm basis. Copyright © 2002 John Wiley & Sons, Ltd.

Abstract This paper introduces an image based method for measuring bidirectional reflectance distribution functions (BRDF). The measurement system uses a CCD camera connected to a workstation to capture images from the material under investigation. The evaluation of the BRDF is performed in an image processing step, gathering BRDF values with a broad range of incident and reflected angles, followed by a fitting process, where these values are approximated by a chosen reflectance model. Absolute BRDF values are obtained by the usage of a diffuse reflectance standard. It is shown that the proposed measurement system produces very reasonable results compared to accurate measurements. Thus, it is an easy and cost efficient way to measure material properties needed for physically based rendering algorithms.