(University of Waterloo, Waterloo, Canada)

Keywords: Retrospective Photogrammetry, 3D archaeology, Legacy data

Retrospective photogrammetric 3D modeling of archaeological sites and monuments using archival photographs has achieved encouraging results as its possibilities and limitations are addressed.I will discuss the limitations posed by both the archiving processes and the use of photogrammetric software with regard to camera calibrations. By eliminating elements that reduce the quality of the modeling, I will show what is involved in achieving maximum detail and accuracy. By the time they become available in a database or online, archival photographs have gone through several steps in processing; each of which diminishes the quality of the final photographs and their ability to be compatible with each other. Based on retrospective photogrammetric projects undertaken in spring/summer 2018 I will demonstrate how archival photographs can be brought to a level that allows them to perform in the same manner as a contemporary equivalent. Using archival photographs of the American School of Classical Studies in Athens, I am reconstructing archaeological sites in the Athenian Agora (Omega house, the State Prison and the Royal Stoa) and in Ancient Corinth (Peirene Fountain, Fountain of the lamps and East Stoa) in order to aid in preservation and assess deterioration. With this goal in mind the accuracy of the 3D modeling is paramount and requires novel approaches to their improvement.

Relevance for the conference: The techniques that I will present allow us to reactivate and reconstruct three dimensionally from previously researched records.
Relevance for the session: My research focuses entirely on using images from the past to recreate and repurpose them in the present
• Wallace, C. (2017). Retrospective Photogrammetry in Greek Archaeology. Studies in Digital Heritage, 1(2), 607-626. @inproceedings{Maiwald2017PhotogrammetricAO, title={Photogrammetric Analysis of Historical Image Repositories for Virtual Reconstruction in the Field of Digital Humanities}, author={Ferdinand Maiwald and T. Vietze and Dorothe Schneider and Frank Henze and Sander M{\”u}nster and Florian Niebling}, year={2017} }