Multiscale acquisition and presentation of very large artifacts

Abstract

The dichotomy between full detail representation and the efficient management of data digitization is still a big issue in the context of the acquisition and visualization of 3D objects, especially in the field of the cultural heritage. Modern scanning devices enable very detailed geometry to be acquired, but it is usually quite hard to apply these technologies to large artifacts. In this article we present a project aimed at virtually reconstructing the impressive (7×11 m.) portal of the Ripoll Monastery, Spain. The monument was acquired using triangulation laser scanning technology, producing a dataset of 2212 range maps for a total of more than 1 billion triangles. All the steps of the entire project are described, from the acquisition planning to the final setup for dissemination to the public. We show how time-of-flight laser scanning data can be used to speed-up the alignment process. In addition we show how, after creating a model and repairing imperfections, an interactive and immersive setup enables the public to navigate and display a fully detailed representation of the portal. This article shows that, after careful planning and with the aid of state-of-the-art algorithms, it is now possible to preserve and visualize highly detailed information, even for very large surfaces.

4d Reconstruction and Visualization of Cultural Heritage: Analyzing Our Legacy Through Time

“…The use of integrated approaches and technologies represents a crucial aspect since CH elements and sites usually present peculiarities that do not allow the definition of standard methodologies and procedures for every situation and context that it is possible to find. In this context, many interesting applications have been developed in recent years (Guidi et al, 2009, Callieri et al, 2011. Investigations have confirmed, on the one hand, that the workflow is often complex and requires expert assessment.…”

3d Digitization of an Heritage Masterpiece - A Critical Analysis on Quality Assessment

“…In a normal situation, to prevent warping and deformations, external rigid references should have been placed and used in the alignment phase, e.g. : using external markers, or having a single scan covering the whole object, taken for example with a terrestrial laser scanner (Callieri et al, 2011). In this case, however, time constraints prevented such strategy.…”

Biharmonic fields and mesh completion

“…As mentioned, our work was initially motivated by the case presented in [1], where a mesh of 173 million triangles with more than 14,000 holes had to be repaired. Cases from real applications like [1] with very large acquired meshes require fully automatic and reliable algorithms. In our opinion, volumetric schemes are well suited to fulfill these requirements.…”

“…The total size of the mesh after registration was in the vicinity of 173 Mtriangles, presenting 14622 holes of different sizes. More details on the project can be found in [1]. Holes and cracks were automatically detected through a search for cycles of border edges, and simple holes could be repaired by projecting their boundary onto a suitable plane and triangulating the projection without adding Steiner points.…”