ABSTRACT:Rotationally symmetric objects commonly occur at archaeological finds. Instead of creating 2D images for documentation purposes by manual drawing or photographic methods, we propose a method based on digitally colored surface models that are acquired by 3D scanners, thereby including color information. We then transform these highly-detailed meshes using simple geometrical objects such as cones and spheres and unwrap the objects onto a plane. Our method can handle curved vessel profiles by dividing the surface into multiple segments and approximating each segment with a cone frustum that serves as an auxiliary surface. In order to minimize distortions, we introduce a simple quality measure based on distances of points to a fitted cone. We then extend our method to approximately spherical objects by fitting a sphere on the surface of the object and applying a map projection, namely the equirectangular projection known from cartography. Our implementation generates true-to-scale images from triangular meshes. Exemplary results demonstrate our methods on real objects, ranging from small and medium-sized objects such as clay cones from the Ancient Orient and figural friezes of Greek vessels to extremely large objects such as the remains of a cylindrical tower of Heidelberg Castle.
Abstract. Challenges in the development of state-of-the-art navigation tools involve the synchronous generation of user-tailored natural language directions and accompanying graphical representations. Of particular interest is the combination of indoor and outdoor scenarios. We describe an architecture for simultaneously generating route directions and suitable visualizations of the navigational context for walking directions. We present a representation model for 3D environments, the spatial model, and a route representation format based on OpenGIS standards, aiming at an elegant and efficient way to support users with and without knowledge about the environment.
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