Dominique Meyer

Fusion of multimodal three-dimensional data for comprehensive digital documentation of cultural heritage sites.

Geometry, appearance and context are essential aspects to capture in the digital documentation of cultural heritage sites. Geometry must be accurate and should provide a level of precision necessary for quantified diagnostics. Visual appearance should capture the “as-is” state, while site specific context is important for correlation, interpretation and analysis. Light detection and ranging (LiDAR) has established itself as the premier laser scanning modality for the acquisition of trusted geometry, while photogrammetry techniques like structure from motion (SfM) are used to construct visually compelling models. A common challenge of these line-of-sight techniques is that the imaging equipment must be systematically moved throughout the target environment to assure that the data captures the entire target and allows for the removal of occlusions in the final model. By combining terrestrial and airborne imaging techniques using unmanned aerial vehicles (UAV), also frequently referred to as drones, it is possible to streamline the acquisition of the target data sets. This paper discusses the fusion of full resolution three-dimensional data streams generated from laser scanning, ground based photogrammetry and drone based photogrammetry. Maintaining full resolution of the data sets allows for diagnostic analysis of very subtle deformations and defects like erosion and cracks. In a presented case study in Mexico, terrestrial laser scanning serves as a geometric scaffold that the photogrammetry data is registered to in order to generate a holistic model of a one hectare site containing two historic structures. The laser scanning and photogrammetry data sets have sufficient overlap to enable fusion, and more importantly the individual sets can supplement each other, providing geometry, photorealism and context that the other set lacks.

Informing Historical Preservation with the Use of Non-destructive Diagnostic Techniques: A Case Study at Ecab, Quintana Roo, Mexico

This paper presents work performed at the northeastern tip of the Yucatan peninsula aiming to assist in the preservation planning for the 16th century church at Ecab. The main goal of the presented work was to accurately document the existing site using non-destructive methodologies in order to perform visual and structural diagnostics off-site. The non-destructive methods used in the two day documentation of the church were 3D laser scanning, stereo panoramas, high-resolution imagery, aerial photography and thermal imaging. Documenting the current state of health is extremely important, and the data acquired can also inform plans for protection and preservation of cultural patrimony. The scope of this project was aimed towards the structural diagnosis and preservation of a historical monument, but the implications of combining all of these diagnostic methodologies reach much farther into the realm of historical, archaeological and anthropological analyses.