Detection of temporal changes of the Omega House at the Athenian Agora

This work presents the role of 3D visualization and analysis of monuments and archaeological sites in producing useful data regarding their preservation condition.The progress made in 3D digitization technologies, in combination with finding new data processing algorithms, have enabled reliable and highly detailed digitization of the characteristics of different parts of the monuments. Due to both the effects of nature and human intervention, monuments and sites all over the world have changed over time. The use of analog documentation data can help significantly towards this direction. In this work, we use as case study a luxurious residential complex in the Athenian Agora, known as Omega house. We use a retrospective 3D model, created with photographs taken in the late 60’s and early 70’s, in comparison with a 3D model made with contemporary digital photos, taken in 2017. All models are georeferenced. The old model is produced using analog terrestrial photographs and aerial photos taken by a blimp. The new one is created by terrestrial digital photographs in combination with images taken by unmanned aerial vehicle commonly known as a drone. The 3D models have been divided into smaller parts so that we can analyze them with greater accuracy separately, and then the whole models were compared between them too. The Constructive Solid Geometry (CSG) modeling scheme is used and Boolean operations are applied to find the difference and intersection of the models.The comparison that is carried out in the current work elaborates on legacy data usefulness and utility for monitoring the Omega House condition. The type of investigation proposed in this work proves that legacy data can be repurposed and attain a new role through change detection techniques.