Multiresolution Techniques for Real-Time Visualization of Urban Environments and Terrains

Abstract

In recent times we are witnessing a steep increase in the availability of data comingfrom real-life environments. Nowadays, virtually everyone connected to the Internetmay have instant access to a tremendous amount of data coming from satelliteelevation maps, airborne time-of-flight scanners and digital cameras, street-levelphotographs and even cadastral maps. As for other, more traditional types of mediasuch as pictures and videos, users of digital exploration softwares expect commodityhardware to exhibit good performance for interactive purposes, regardless of thedataset size.In this thesis we propose novel solutions to the problem of rendering large terrainand urban models on commodity platforms, both for local and remote exploration.Our solutions build on the concept of multiresolution representation, where alternativerepresentations of the same data with different accuracy are used to selectivelydistribute the computational power, and consequently the visual accuracy, where itis more needed on the base of the user's point of view.In particular, we will introduce an efficient multiresolution data compression techniquefor planar and spherical surfaces applied to terrain datasets which is able tohandle huge amount of information at a planetary scale. We will also describe a noveldata structure for compact storage and rendering of urban entities such as buildingsto allow real-time exploration of cityscapes from a remote online repository.Moreover, we will show how recent technologies can be exploited to transparentlyintegrate virtual exploration and general computer graphics techniques with webapplications.