ASSESSMENTS FOR 3D RECONSTRUCTIONS OF CULTURAL HERITAGE USING DIGITAL TECHNOLOGIES

摘要

The aim of this contribution is to show the results of evalua tions on 3D digitizations perform ed using different methodologies and technologies. In particular, for surveys conducted at the archit ectural and urban scale, the recent reduction of costs related to Time of Flight and phase shift laser scanners is actually enhancing the replacement of traditional topographic instruments (i.e. total stations) with range-based technologies for the acquis ition of 3D data related to built heritage. If compared to surveys performed using traditional topographic technologies, range-based ones offer a wide range of advantages, but they also require different skills , procedures and times. The present contribution shows the results of a practical application of both approaches on the same case study. Another application was suggested by the recent developments in the photogrammetric field that enhance the improvement of software able to automatically orient uncalibrated cameras and derive dense and accurate 3D poi nt clouds, with evident benefits in reduction of costs required for survey equipment. Therefore, the presented case study constituted the occasion to compare a range-based survey with a fast 3D acquisition and modelling using a Structure from Motion so lution. These survey procedures were adopted at an architectural scale, on a single building, that was surveyed both on the outside and on the inside. Assessments on the quality of the rebuilt information is reported, as far as metric accuracy and reliability is concerned, asw ell as on time consuming and on skills required during each step of the adopt ed pipelines. For all approach es, these analysis highlighted advantages and disadvantages that allow to conduct evaluations on the possible conve nience of adopting range-based technologies instead of a traditional topographic approach or a photogrammetric one instead of a range based one in case of surveys conducted at an architectural/urban scale.