3D Scanning and Photography at Villa Arianna, Stabiae
In collaboration with the Restoring Ancient Stabiae (RAS) foundation, three researchers from the University of Arkansas visited the ancient Roman city of Stabiae in June of 2010 with two goals; 1. to acquire laser
scanning data of the exposed garden surface of the Villa Arianna, together with
rooms adjacent to the garden and peristyle, and 2. to acquire a set of
high resolution photos for the scanned rooms appropriate for digital texturing. The scanning and photography data for the rooms adjacent to
the garden contribute to the larger goal of a complete laser scan of the Villa,
essential for documentation and conservation.
This data will also be used to construct an accurate 3D model of this
portion of the Villa. Instruments used in the field included a Zoller+Fröhlich (Z+F) Imager 5006i 3D laser scanner and Canon 5D Mark II DSLR camera.
CAST is grateful to the Restoring Ancient Stabiae foundation for their assistance in arranging the scanning program, and to the hospitality of the Vesuvian Institute during our stay. Special thanks to Matthew Bell, Thomas Howe, and Ian Sutherland for sharing their expertise, and to Kameron Aroom for his help with the digital photography.
Scanning:
A total of 40 high density laser scans were collected for the garden surface and adjacent rooms using a Z+F 5006i (right). This is a 360° x 310° scanner empoying phase-based measurement technology and is well suited for exterior scanning at moderate range and scanning interior rooms. For most scans, color photographs were also collected using the Z+F M-Cam. This is a factory calibrated camera that mounts to, and communicates with, the scanner during data collection.
Scan data is being processed with the software packages Z+F Laser Control, Leica Cyclone, and InnovMetric Polyworks 11. Point spacing for raw point clouds are sub-centimeter for interior surfaces (walls and floors), and 1-3 centimeter for outdoor ground surfaces. Once each point cloud has been cleaned (removal of noise and undesirable objects) and co-registered, the unified dataset will be registered to the local coordinate system using a number of previously surveyed control points visible in the scan data.
Photography:
Flash photography using a Canon 5D Mark II digital SLR
camera was completed for 10 rooms within Villa Arianna, including three floors
with extant mosaics. Images were
captured in two formats: the Canon RAW format as well as JPEG Fine. Some other
exterior walls (most notably the large wall west façade of the peristyle facing
the garden were also photographed, bringing the total number of walls
photographed to 44. A total of 657 photos were required to cover these walls
and floors.
The photographs were captured with the camera sensor approximately orthogonal to the wall surface, and at a distance of four to ten feet depending on the conditions. The camera was moved from left to right between each photo, and up or down between each row of photos (below). Each time the camera was moved, overlap between sides and ends (between rows) was manually checked.
In order to have evenly distributed lighting of a known color temperature, Canon Speedlite flashes were used for all photography and camera settings were adjusted to avoid ambient light. A Canon 580EX flash unit was mounted on the camera and used as the “master” flash, while two Canon 430EX flash units were set as “slave” flashes. This system allowed for the slave flashes to be handheld, and therefore easily aimed where needed. Photography of tiled floors was performed using a tripod fitted with a 24” tripod arm.
The photograph sets for each wall/floor were stitched together to make a composite view. This process requires a number of software packages, including PhotoModeler Pro 6, Z+F Laser Control, ArcGIS 10, and Photoshop CS4. See below for example finished mosaics.
Wall mosaic, Villa Arianna, Stabiae
Floor mosaic, Villa Arianna, Stabiae
Center for Advanced Spatial Technologies
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