Abstract
This contribution presents the results of investigations on the reliability of techniques based on the Structure from Motion approach used for 3D digitizations of build heritage. In particular, we tested the performances of different SfM technologies within an architectural survey context and we developed a procedure with the purpose of easing the work of surveyors called to restore digital representations of artifacts at different scales of complexity. The restored 3D models were compared among each other and with a gold standard acquisition. These analysis led to qualitative and quantitative evaluations and to considerations on times and skills required by all tested technologies. In this work strengths and weaknesses are highlighted and the integration of different technologies is presented, as it represents the best solution in many and recurrent multi-scalar contexts.
TopBackground
One of the most important consequences of the widespread use of range-based technologies in the Cultural Heritage field is the possibility to easily and quickly acquire huge amount of 3D information which can be used for different purposes that can change through time. These possibilities are actually modifying the expectations of users called to collect information about sites and artifacts, since they are widening the need to acquire complex and versatile data to be used in different contexts and for different communication aims. Despite these achievements, range sensors are still very expensive, need expertise and present persistent bottlenecks both in the reverse modeling process and in time consuming that often limit the possibilities of their widespread use.
During the last decade, the developments in the high-resolution digital photogrammetry field showed that 2D images can be used as tools able to derive detailed and accurate measures, as well as to record information on the radiometric characteristics of artifacts. These achievements, together with the lowering of costs of range sensors are actually offering the possibility to widen the digitization of sites and artifacts and are also stimulating investigations on the possibilities of their integration with the purpose of optimizing both final results and the whole pipeline [Velios and Harrison 2002; Guidi et al. 2002; Böhler and Marbs 2004; El-Hakim et al. 2004; Remondino 2011; Manferdini and Remondino 2012].
Key Terms in this Chapter
Multi-Scalar: Property that allows to cross different scales of complexities of an artifact.
Integrated 3D Model: 3D model derived from the combined use of different techniques.
Reality-Based 3D Modeling: Process of 3D modeling that starts from surveyed data and ends with a 3D digital mold of the real artifact.
Optimization: Reduction of redundant and not necessary information or procedures.
Image-Based Survey Techniques: Surveying methodologies based on image acquisition from which spatial dimensions are derived.
Metric Reliability: Ability to acquire a sequence of 2D/3D measurements similar in terms of accuracy or uncertainly.
Range-Based Survey Techniques: Surveying methodologies that derive spatial information using range systems, based on different approaches like laser or pattern projection.