INSIGHT uses several different digital techniques. All tools used for site recording are designed to serve the needs of the host project’s research team. The following tools are offered as a representative sample.
Five main digital techniques are used, as described below.
Any fieldwork calls for both traditional and digital photographs. But the true advantage of digital photography is its intrinsic liberation from film. With digital photography, thousands of images can be made of a site, allowing the photographer the luxury of total documentation. Importantly, these digital photos are readily archived on CD-ROM / DVD-ROM. Digital photographs are intended for use as:
As demonstrated by Dr. Nigel Strudwick’s excellent web sites, digital panoramas can provide a thoroughly engaging introduction to archaeological sites. Happily, these panoramic photographs, used to give a viewer an interactive sense of place, can be made very quickly and cheaply in the field. Whether the viewer navigates within a virtual panorama (as with Apple’s QuickTime VR standard) or is able to rotate the subject in question (this is often termed an “object movie”), the technical underpinning is the same. Stitching together digital photographs generates the navigable view.
By digitizing conventional drawings, the resulting images can be freely scaled, compared with other pictures, and manipulated for both color and legibility. A brief example follows. For the low-relief epigraphy present at the Zayiwa and Sabil of Farag ibn Barquq in Cairo, INSIGHT first completed conventional ink drawings on acetate. Next, these drawings were scanned and then digitally scaled, preserving the precision of the original full-scale drawing. The resulting digital images were then directly printed and archived, without losing fidelity to the original through optical enlargement. Additionally, the digital files could then be referenced directly to the 3D data taken from the structure, creating an index.
Where possible, INSIGHT gathers data in several formats. For INSIGHT’s Phase II projects in Egypt, a handheld acoustic device was used to verify the accuracy of the laser scan data. The device produced results accurate to (+/- 1 cm); these objective point-to-point measurements were then compared to the measurements drawn from scanned data.
Laser scanning can be used to create an image of an object in space, but the construction of this image comes by a very different method than is used in conventional photography. When a photo is taken, the image is captured through a lens. The specifications of the lens determine the observed perspective in the final image; also, the lens introduces distortions that make it difficult to extract accurate drawings or measurements. The orthographic drawings commonly used by architects and engineers are drawn without perspective so that relationships between any given points on the drawing can be measured at a constant scale.
Laser scanning measures the distance from the scanner, itself, to specific points along an object. After making these measurements, the relationship between the gathered points can be expressed in the synthetic 3D space of the computer. By taking thousands or millions of measurements, a “cloud of points” emerges, which accurately describes the subject being scanned. Finally, when rendered from the point of view of a synthetic camera in the 3D world space of the computer, accurate orthographic and perspective drawings are generated.
A more detailed treatment of the laser scanning process is offered here: LASER SCANNING
The analysis of field data is a crucial step in the INSIGHT Project Model. Once fieldwork is completed, through traditional or digital techniques, it must then be prepared in accordance with the criteria for its final presentation. Here there are no hard rules, and all work is determined in concert with the host organization. If the final output will be publication in a journal, the data will be presented as needed, from simple line drawings to false-color images and structural analyses. If the goal of the work is to create architectural drawings, another set of steps will be taken to bring the work into a CAD package (e.g., AutoCAD). If a photo realistic reconstruction is being attempted, then an appropriately realistic visualization of the data will be made, including digital textures and lighting. If the end result is intended as a short film, steps will be taken to create the necessary character or environmental animation and render the result. Each application must be treated individually, and requires different tools. A list of important hardware and software issues is included in the section below.
Traditional polygonal mesh imaging
Field of point display (Qsplat)
Implicit NURBS surfacing (Paraform)
Over time, INSIGHT has made contact with a broad range of visual computing companies, both hardware and software providers. This dialogue with the computer industry will be actively maintained. It is hoped that communication will lead to a better understand evolving hardware and software and their potential applications in cultural heritage work. Posited as a conduit for understanding between the Archaeology community and their technical colleagues, INSIGHT industry outreach is not tied to any proprietary system or companies. Instead, this outreach effort would draw from the existing spectrum of technology. The goals for INSIGHT Industry Outreach are:
Throughout Phase III and IV, INSIGHT will continue to monitor developments in space sampling technologies, and their associated visualization counterparts.