From ground surveying to 3D laser scanner: A review of techniques used for spatial documentation of historic sites

Abstract

Modern technology has changed matters in documentation radically and promises to continue to bring rapid changes. Photographic and non-photographic (graphic) documentation tools are merging in one process, in which the digital photographic technology is the main base. 3D supports are still not popular among users involved in documentation of historic sites. Due to the digital technology, actually, there is an increasing gap between the specialized technician and non technician users. However, in order to build a bridge between the specialized technical and non technical users, a dialogue between them must now be created. They should not only discuss issues of data precision required and 3D accuracy standards, but simultaneously should discuss issues of achieving visualization production system, which can now be actually easily achieved by the modern digital photographic technology. This paper intends to present a review of the evaluation of historic sites documentation methods and survey techniques now available, focusing on the needs and requirements of the non-technical experts and users. It attempts to clarify some new aspects in documentation methods for the non-technical experts and users, and the impact of current technology in its quick development. This will be achieved through a comparative evaluation of the potentials of the application of digital methods in documentation, and in view of the main obtained quality, accuracy, time, costs and specific skills required. This evaluation covers traditional and pre electronic techniques to 3D laser scanning, which represents today the most advanced technology available for measuring and documenting objects, structures and landscapes.

Integration of Laser Scanning and Imagery for Photorealistic 3D Architectural Documentation

“…In the photographic methods, the entire vicinity is quasi completely determined, point by point, and the filtration for the extraction of the essential points happens later, meanwhile a relevant difference arises in the acquisition process in situ, compared to a laboratory process. This concept is completely different from the graphic documentation process, where the in situ needs more time (Haddad, 2007;Haddad, 2010). However, a shadow always causes errors in the results, because certain picture information is lost.…”

Using an Imaging Station in making a 3D model of a complex cultural and historical heritage object

“…Zaščita in ohranjanje kulturnih krajev, raziskovanje in uporaba dobljenih rezultatov so vse večkrat podprti z digitalnimi mediji in odvisni od njih. Z gotovostjo lahko zatrdimo, da so dokumentacijska orodja v zadnjih dvajsetih letih zelo napredovala (Haddad, 2011). Na področju kulturne dediščine lahko velikost objektov sega od zelo majhnih do gigantskih struktur, in tako zajema spomenike, skulpture, artefakte, mumije, grobove, grobnice, amfiteatre in arheološka najdišča.…”

Can 3D Point Clouds Replace GCPs?

“…Although the point clouds produced by 3D laser scanners are immediately rich data sets, in most cases they are not directly usable in raw format and the majority of commercial software does not fully support them. Therefore, they usually have to be converted to triangle mesh models prior to any application (Haddad, 2011). As the generation of triangular mesh is a computationally intensive and, hence, time-consuming process, recently attempts have been made to take advantage of the primary form of 3D point clouds.…”