This presentation is part of the 2017 3D Digital Documentation Summit.
Cloud Based 3?D Digital Photogrammetry Pertev Pa?a Mosque (Izmit, Turkey)
The use of photogrammetry as a tool to aid in the documentation of cultural heritage has a long history as a means to create scalable documents from 2?D photographs. Recent advances in technology paired with availability of cloud?based processing present ever growing opportunities to document heritage sites. This can be achieved with minimally training, a consumer?grade camera or smartphone, and an internet connection. Application dependent web servers manage almost the entire photogrammetric process, including image registration, object matching, photo?stitching, 3?D mesh generation and rendering. These cloud based applications make 3?D photogrammetry more accessible and cost?effective as ever.
The increasingly rapid advancements in photogrammetric technology have become possible due to significant progress in calculation software, three?dimensional generation software, automation, and sensor technology. Digital 2?D images captured from consumer grade cameras, combined with the development of easily access photogrammetric software, provide opportunities to document heritage sites quickly, easily, and without the need for expensive, difficult to transport equipment. There is no longer the need for time consuming post image capture processing to orient and stitch together images to generate a useable model.
This paper presents the application of digital photogrammetry completed of the 16th century Pertev Pa?a Mosque in Izmit, Turkey using close?range, cloud based 3?D photogrammetry. Pertev Pa?a Mosque is a single domed mosque completed in 1579 built during the Ottoman reign of Selim II. Located at the eastern end of the Sea of Marmara in the city of Izmit, it is part of a complex that includes walled courtyard with gates, a fountain, and a school. The mosque sustained damage during an earthquake in 1999.
Cloud Based Digital Photogrammetry starts with the on?site collection of digital photographs. While the photographs can be taken with a device as common as a smart phone, a camera with greater resolution, clarity, and picture quality will produce a more accurate and detailed digital 3?D model. Digital SLR cameras with a quality lens are capable of capturing information in order to have consistency and quality. Field planning prior to capturing the photographs include a few control measurements to provide accurate scale to the finished 3?D model. Variables such as lighting, access, obstructions, and photo sequence are important considerations, especially with complex subjects or subjects with repetitive features. With proper planning, the required photography can be completed quickly. The interior 3?D model of the Pertev Pa?a Mosque was created utilizing 235 photographs which were captured in less than two hours.
Photographs are uploaded to the cloud?based server for processing by automated modeling software (i.e. Autodesk ReMake). The software analyzes the 2?D images to create a 3?D polygonal textured mesh model.
The 3?D mesh models are generated as several file types. These files can be downloaded to a local computer for post processing or manipulations. For example, for larger projects, multiple 3?D Mesh models can be created and merged together. A building’s interior 3?D model can be inserted into the 3? D mesh model of the building’s exterior. This can be done with a surface modeling software (i.e. Maya or Rhino). In the case of Pertev Pa?a Mosque, the model was further refined through Maya and Mudbox to eliminate “ballooning” and other deviant geometry inherent to the photogrammetry process.
Through cloud?based 3?D photogrammetry, the ability to accurately document heritage sites, even in remote locations, is more accessible than ever before. There are still challenges to be overcome, such as the scale of the building, occlusions, and repetitive details. This method does have a base level of dimensional accuracy, it does not have the precise dimensional accuracy of 3?D laser scanning. However, the low cost, accessibility, minimal field time, and simplicity of use make it a viable options in our documentation tool bag.
Jonathan Spodek, FAIA, FAPT is a Professor of Architecture at Ball State University teaching in the areas of architectural design studio and building technology that include building documentation, historic building construction materials and techniques, and evaluation/diagnostic methods. Jonathan’s research interests focus on non?destructive building evaluation. For more than ten years, Jonathan has co?lead international workshops on Heritage Conservation exposing a diverse group of emerging architects to international perspectives of building conservation, architecture, and heritage. Beyond the university, Jonathan has been involved with several professional organizations including the American Institute of Architects, the Historic American Buildings Survey, and the Association for Preservation Technology.
Christopher Harrison, Assoc. AIA is an architectural graduate and Virtual 3D Designer and Modeler for the Institute for Digital Intermedia Arts (IDIA Lab) at Ball State University. Chris was part of the team to digitally recreate Hadrian’s Villa working with virtual archaeologist and scholar Dr. Bernard Frischer. He is currently working on the digital photogrammetry of the pre?historic earthworks of the native American Adena?Hopewell people at Indiana’s Mounds State Park.