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Top3D Digitization Of Cultural Heritage
3D digitization of Cultural Heritage has been attracting the attention of many researchers since long time and the literature about it is huge. Just considering the two last big innovations in the production of 3D models, the application of laser scanners to Cultural Heritage and the image matching approach or Structure from Motion (SfM) technique, many papers may be found.
Pieraccini et al. (2001) or Pavlidis et al. (2007) try to summarize most of the available methods for 3D digitization that can be applied to the digital recording of Cultural Heritage. Boehler et al. (2002) highlight the potentiality of Laser scanning instruments that were mainly developed for industrial applications, for Cultural Heritage recording as well: in the vision of the authors this method would complement, and, in certain applications, replace currently existing methods. The advantages of laser scanning approach are evaluated against photogrammetry. Lichti and al. (2002), highlight the high acquisition rate, the relative high accuracy and high spatial density as the three key advantages of laser scanning; besides, the authors, just like Kadobayashi et al. (2004) and Boehler et al. (2004), compare laser scanning and photogrammetry and their combined use to produce accurate and expressive models of Cultural Heritage objects and of the efficiency of the data processing pipeline; as a result, due to the great variety of Cultural Heritage objects, no single method is applicable to recording every subject of Cultural Heritage and hence there is a strong demand for a hybrid method that exploits several technologies. The authors also highlight that it is difficult to define a strict guideline in that sense and that practical experience and the accumulated know-how are essential. However, photogrammetry is appreciated for the color information it has and the fact it eases the interpretation of 3D data. Eisenbess et al. (2006) compare Digital Surface Model (DSM) coming from laser scanning and digital photogrammetry, and highlight the comparable precision that can be achieved by using the two methods; the main difference is in the occlusions that the shooting positions may have. The integration of the two approaches is also highlighted by Beraldin (2004) as the most appropriate way to digital recording Cultural Heritage. The integration between laser scanning and photogrammetry led to new survey products: Bornaz at al. (2002) invented the concept of Solid Image, that thanks to the new surveying methods is easily produced. Also, orthophotos take advantage of the fact that building a Dense Digital Elevation Model (DDTM) is at hand, so True Orthophotos, Dequal et al. (2001), offer a higher fidelity and accuracy.