The three main methods of digitization can be broadly defined as contact digitization, image-based digitization (photogrammetry), and geometry-based digitization (laser scanning). With the development of the latter two digitization methods, and advanced rendering technologies, virtual displays and museums can now be used widely. (Hung, 2007) Furthermore, recent developments in interactive 3-D computer graphics technology have seen an increased interest in, and use of, 3-D digitization for cultural heritage objects. (Muller-Wittig, Zhu, & Voss, 2007) Technologies for reconstructing or remodeling physical components in 3- D formats are not new in the engineering field, in particular within manufacturing engineering. However, 3-D digitization used for the preservation and archiving of cultural artifacts is relatively recent.
Digitization of artifacts is the process of converting spatial and color information into digital formats. 3-D digitization refers specifically to creating a digital representation of an object in three spatial dimensions, that is, Cartesian x, y, and z coordinates. During 3-D digitization, depth, size, proportion, and textural information about the artifact are recorded and stored in electronic form.
There are a wide range of techniques available in the field of 3-D digitization. The specific approach to digitization differs depending on the artifact and the final intended application of the data. The overall process of 3-D digitization involves three broad steps, as shown in Figure 1. Data are acquired using a method of determining and recording the spatial details of the artifact. The raw data are then processed to form complete rendered 3-D models, and then the data are applied to its intended purpose.
Overall digitization process
3-D digitization of artifacts is an effective method of archiving historic information. It is currently used within museums and other organizations for documentation and security purposes. Furthermore, electronic models give museums the ability to display digital models on the Internet, increasing public awareness and accessibility to the cultural artifacts. The models also facilitate the use of digital interactive displays within museums, allowing viewers to explore objects without risk of damaging the original artifact. Digital information can also be supplied to computer numerical control (CNC) machines to manufacture accurate replicas or support pieces for artifacts. A further application of digitized data is in analysis of artifacts for historical restoration.Top
Current Digitization Practices
A number of organizations, worldwide, are promoting research into the digitization of cultural artifacts. These include the Canadian Heritage Information Network (CHIN), the Virtual Heritage Acquisition and Presentation (ViHAP3D) project in Europe, and the Salzburg Research Institute (SRI) in Austria. Some museums are working in collaboration with universities to further research in digitization; in 2004, approximately 35% of museums, worldwide, had initiated developments in some form of 3-D digitization of objects (White, Mourkoussis, Darcy, Petridis, Liarokapis, Lister, et al., 2004). These include the Museum of New York, the Royal Ontario Museum, the Museum of Science Boston, and the American Museum of Natural History. Efforts to establish entire “virtual museums” include The Canadian Museum of Civilization and the National Research Council of Canada collaborating on the production of the Inuit3D Virtual museum, launched in April 2001, and the Computer Science Department of Zhejiang University developing a 3-D Dunhuang cultural relic exhibition system in 2004. (Zhang, Pan, Ren, & Wang, 2007)
Key Terms in this Chapter
Point cloud: The collection of points in 3-D space resulting from scanning an object
Triangulation: Within postprocessing of digitized spatial information, the creation of faces or surfaces by joining vertices according to spatial distribution to create triangular planes.
Stereoscopic: Two 2-D images that, when combined, give depth perception.
RapidForm: A comprehensive suite of software designed to convert real-world data from 3-D scanning devices into high quality, accurate, and useful data for a variety of applications.
ICF: INUS compression format file for publication
SRI: (Salzburg Research Institute): An institute fully owned by the Province of Salzburg, specializing in digital media
ViHAP3D: Virtual heritage high quality 3-D acquisition and presentation – a project founded by the European Union deigned to increase public awareness of Europe’s most precious artefacts and documents.
CHIN: Canadian Heritage Information Network – a network of professionals and volunteers whose objective is to promote the development, the presentation, and preservation of Canada’s digital heritage content for current and future generations.