Dr. Christian Leblanc of the CNRS mission to Western Thebes leads the archaeological team at the Ramesseum, the Temple of Ramses II. Since 2000, INSIGHT has contributed to the ongoing scientific exploration of the Ramesseum, the Mansion of Thousands of Years of Ramses II. In this short article, we present an overview of three collaborative CNRS/INSIGHT projects.
Despite significant dismantling and reuse in antiquity, the Ramesseum is a remarkably complete example of a Ramesside temple. Though smaller and less complete than the neighboring Temple of Ramses II, Medinet Habu, the Ramesseum is unique for its intact mudbrick vaults outlying the central stone temple. In the image below, the Sanctuary footprint is seen in the foreground, with the portal to the Hypostyle Hall beyond.
For an interactive look at the Ramesseum, try the RamsesFlex Viewer created for INSIGHT by Antonio Hui.
Pictured below is a panoramic view of the Ramesseum's Hypostyle Hall, one of dozens of panoramas the RamsesFlex viewer is built around. We found that traversing complex environments using panoramas has key advantages when compared with viewing traditional photographs. When we asked people to find a specific object using both RamsesFlex and a set of photos, we found a significant speed advantage. Importantly, the measured speed advantage of the panoramic viewer increased nearly exponentially with the size of the environment. On a more prosaic level, we feel that viewers such as RamsesFlex are generally useful to archaeologists who need effective photographic reference when away from the site. It is common for field seasons in Egypt to be between 4 and 15 weeks; the rest of the year the researchers don't have the luxury of consulting the monuments themselves when a question presents itself.
The first collaboration between INSIGHT and the MAFTO was organized around a need that had gone unmet in the regular course of the French Mission's work efforts. MAFTO had cataloged hundreds of fragments from a gigantic granite royal colossus of Ramesses II, whose impressive remnants inspired the famous 'Ozymandias' verses from Shelly. The fragments had been studied in the 1990s, leading to a preliminary scientific publication. In the early 2000s, the site management plan for the Ramesseum complex called for exploring possible reconstruction of the colossus from its preserved remnants. The aim was two-fold. First, the goal was to validate the hypothetical scientific reconstruction of the colossus. The second main goal was to assess the impact of various physical reconstruction options on the site as a whole, with specific attention paid to the Ramesseum's first and second courts.
At the start of the project, a preliminary reconstruction had been proposed by sculptor Daniel Esmoingt. While this work offered a useful starting point for discussions, it could not convey the precise information needed for an accurate evaluation of the physical reconstruction project. Accordingly, the joint MAFTO/INSIGHT team opted to build a precise, physically-based model of the giant using a capture technique known as optical triangulation, a popular subset of tools known collectively as “3D scanning”. While 3D scanning was already established as a commonplace technology by 2000 for civil engineering projects, the high cost of the equipment required meant that its use in archaeological projects was highly limited.
Our raw data now compiled, next we considered our data processing pipeline, which had to be devised from scratch. At the time, no commercial software packages were able to handle large data sets of the kind we had captured – the scale of the project and number of individual scans were exceedingly heavy. Therefore, our pipeline evolved greatly during the project. We began with a toolset created by Stanford University, a Linux application titled Scanalyze. Dr. Marc Levoy at Stanford contributed his source code for iterative closest point alignment (ICP); because of this generous sharing we were able to build and extend our own implementation. We used a then-innovative approach for aligning large amounts of 3D data; we maintained the scan data in a compact, memory-conserving point representation and converted to polygons only after all constituent point clouds were registered. The resulting polygon meshes were procedurally textured and finally rendered into images for review by the MAFTO staff. Though these approaches might be seen as relatively casual today, they were not trivial a decade ago.
As above, MAFTO/INSIGHT has built an architectural model of the entire Ramesseum complex. Through a visual and practical assessment of potential reconstructions, options were rejected or validated. Such an endeavor can never be seen as finished. But the graphical output from our first stages displays for the first time a faithful representation of a knowledge base gathered during more than thirty years of scientific activities, in a very alluring and meaningful mediation. It is thus our goal and responsibility to keep this data gathered to date alive and to implement it as the central core of our scientific documentation. The data archive is useful for the MAFTO archaeological team in charge of studying the site, as well as our colleagues from the SCA responsible for the management of the monument. It also has proven useful to a wider audience eager to learn about the Ramesseum and its many dimensions and changing faces. The digital model of the site has been shared with a wide audience through a website and three documentary films.
One of the limitations we encountered during the different stages of our 3D scan survey was the relatively poor quality of the color data gathered by the digital cameras incorporated in the scanner sensors. To compensate, we elected to record high quality color calibrated photographs to be used together with the 3D data acquired on site. The task at hand was more complex than first estimated. Most of the ancient spaces are crowded with pillars or columns limiting the photographic vantages possible and thus forcing us to multiply the number of exposures necessary to cover the hundreds of square meters of surfaces at the Ramesseum. Furthermore, the preservation state of the temple means that in the same space, some walls are never lighted by direct sunlight while others are never seen in homogenous shade.
To avoid having to build gigantic and impractical scaffolds, INSIGHT devised a tall tripod made out of aluminum, supporting a photographic gantry set on a moving chariot. The tripod can reach nearly 15 meters in height but remains highly compact in its footprint. The tripod's base is indeed small enough to easily negotiate the cramped spaces of the hypostyles and porticos and light enough to be moved somewhat easily by a limited crew. The digital camera set on the Uberpod, as the contraption was baptized, is linked to a computer that enables us to check the coverage for each photograph while precisely monitoring speed and bracketing on the camera. The operator, wirelessly connected, remains on the ground. To neutralize the existing differences in lighting, a flash was used. Each frame was imaged several times with different bracketing to gather High Dynamic Range (HDR) information.
The flexibility and mobility of the Uberpod enabled the photographic documentation of all the inscribed surfaces of the stone temple in a record time-span, delivering an incredible output of thousands of digital images shot in a relatively controlled and optimized lighting context. However, the tight spatial setting of the Uberpod forced us to use a wide-angled lens, bringing with it optical deformations and aberrations that need to be corrected before the different images of a wall surface can be aligned in a high-resolution photomosaic. This part of the work is still in a state of rdevelopment and is in need of continued funding. We hope to be able to use the 3D data set gathered through 3D scanning as a virtual scaffold to help us to ensure the metric validation of each photographic mosaic, as shown in the example illustrated above. Orthomosaics are useful not only as digital texture maps but also as a precise and neutral photographic archive documenting the state of the decorated surfaces of the Ramesseum. These images, if successfully completed, will also be used in the digital epigraphic survey of the highest portions of the monument – such as the monumental dedicatory texts decorating the different lines of architraves. This would enable more speedy progress of this part of the epigraphic documentation of the monument without the need for slowly moving bulky scaffolding.
The data gathered during the past decade is a testimony to the extent of the work completed and to the quality of its output. However, as with any information gathered on an archaeological site, the work is only partially done and the goal only partly achieved. We still need to process a large part of our data sets to render them usable by the researchers in charge of the monument’s study and publication. We intend to make these results accessible to a wide audience through analog publications, a web site and open media. We have also seen evidence that visual media are often easier for the public to grasp than complex Egyptological publications for specialists. It is our hope that our data can be shared freely by a growing community who shall chose to support the archaeological exploration of the site as well as its never-ending documentation. Though significant progress has been achieved, the remaining part of the task at hand is both exciting and humbling.
The Smithsonian Museum's work in 3D Digitization. INSIGHT Board member Kelly Roberson brought the Smithsonian's recent 3D work to our attention, including publicly accessible data for 3D printing similar to INSIGHT's Maya Skies Archive (www.mayaskies.net). To read more about the Smithsonian's plans, please see this news story: http://www.cbc.ca/news/technology/smithsonian-museum-artifacts-can-now-be-3d-printed-at-home-1.2424898
Current Questions in Authenticity. This day-long symposium at UC Berkeley will be held February 3, 2012, as is open to the public. Several people on the INSIGHT team will be participating. The event is free and open to the public; RSVP to:
INSIGHT's Kevin Cain is serving on the International Scientific Committee for VAST 2011. The International Symposium of Virtual Reality, Archaeology and Culture Heritage (VAST) conference will be held October 18-21, 2011, in Prato, Tuscany, Italy. Kevin previously co-chaired VAST 2004, gave the keynote for VAST 2003 and has presented papers in other years.