Bernard Frischer

Research challenges for digital archives of 3D cultural heritage models

The increasing creation of 3D cultural heritage models has resulted in a need for the establishment of centralized digital archives. We advocate open repositories of scientifically authenticated 3D models based on the example of traditional scholarly journals, with standard mechanisms for preservation, peer review, publication, updating, and dissemination of the 3D models. However, fully realizing this vision will require addressing a number of related research challenges.n In this article, we first give a brief background of the virtual heritage discipline, and characterize the need for centralized 3D archives, including a preliminary needs assessment survey of virtual heritage practitioners. Then we describe several existing 3D cultural heritage repositories, and enumerate a number of technical research challenges that should be addressed to realize an ideal archive. These challenges include digital rights management for the 3D models, clear depiction of uncertainty in 3D reconstructions, version control for 3D models, effective metadata structures, long-term preservation, interoperability, and 3D searching. Other concerns are provision for the application of computational analysis tools, and the organizational structure of a peer-reviewed 3D model archive.

Three-dimensional acquisition of large and detailed cultural heritage objects

Cultural heritage digitization is becoming more common every day, but the applications discussed in the literature address mainly the digitization of objects at a resolution proportional to the object size, using low resolution for large artifacts such as buildings or large statues, and high resolution for small detailed objects. The case studied in this paper concerns a huge physical model of imperial Rome (16xa0×xa0 17.5xa0m) whose extremely small details forced the use of high resolution and low noise scanning, in contrast with the long range needed. This paper gives an account of the procedures and the technologies used for solving this “contradiction”.

Virtualizing ancient Rome: 3D acquisition and modeling of a large plaster-of-Paris model of imperial Rome

Computer modeling through digital range images has been used for many applications, including 3D modeling of objects belonging to our cultural heritage. The scales involved range from small objects (e.g. pottery), to middle-sized works of art (statues, architectural decorations), up to very large structures (architectural and archaeological monuments). For any of these applications, suitable sensors and methodologies have been explored by different authors. The object to be modeled within this project is the Plastico di Roma antica, a large plaster-of-Paris model of imperial Rome (16x17 meters) created in the last century. Its overall size therefore demands an acquisition approach typical of large structures, but it also is characterized extremely tiny details typical of small objects (houses are a few centimeters high; their doors, windows, etc. are smaller than 1 centimeter). This paper gives an account of the procedures followed for solving this contradiction and describes how a huge 3D model was acquired and generated by using a special nmetrology Laser Radar. The procedures for reorienting in a single reference system the huge point clouds obtained after each acquisition phase, thanks to the measurement of fixed redundant references, are described. The data set was split in smaller sub-areas 2 x 2 meters each for purposes of mesh editing. This subdivision was necessary owing to the huge number of points in each individual scan (50-60 millions). The final merge of the edited parts made it possible to create a single mesh. All these processes were made with software specifically designed for this project since no commercial package could be found that was suitable for managing such a large number of points. Preliminary models are presented. Finally, the significance of the project is discussed in terms of the overall project known as Rome Reborn, of which the present acquisition is an important component.

Rome Reborn

Rome Reborn (www.romereborn.virginia.edu) is an international initiative, started in 1996 and based at the Institute for Advanced Technology in the Humanities (IATH; see www.iath.virginia.edu), to create 3D urban models illustrating the development of ancient Rome from the first settlement in the late Bronze Age (ca. 1,000 B.C.) to the depopulation of the city in the early Middle Ages (ca. A.D. 550). Other institutional partners have included the Politecnico di Milano, UCLA, the Université de Caen, and the Ausonius Institute at the Université de Bordeaux-III. Commercial rights to Rome Reborn have been exclusively licensed to Past Perfect Productions s.r.l., a corporation based in Rome, Italy (http://www.pastperfectproductions.com/).

3D digitization of a large model of imperial Rome

This paper describes 3D acquisition and modeling of the Plastico di Roma antica, a large plaster-of-Paris model of imperial Rome (16/spl times/17 meters) created in the last century. Its overall size demands an acquisition approach typical of large structures, but it is also characterized by extremely tiny details, typical of small objects: houses are a few centimeters high; their doors, windows, etc. are smaller than 1 cm. The approach followed to resolve this contradiction is described. The result is a huge but precise 3D model created by using a special metrology laser radar. We give an account of the procedures of reorienting the large point clouds obtained after each acquisition step (50-60 million points) into a single reference system by means of measuring fixed redundant reference points. Finally we show how the data set can be properly divided into 2/spl times/2 meters sub-areas for allowing data merging and mesh editing.

Virtualising ancient imperial Rome: from Gismondi's physical model to a new virtual reality application

This paper deals with two, related topics: the acquisition and recovery of information trapped in the geometry of an historical artifact; the employment of this form of intangible heritage as an historical source on a par with more explicit sources such as ancient drawings, books, archaeological excavations, etc. This study relates to the construction of a virtual model of ancient Rome within the framework of the international project known as Rome Reborn 1.0 (www.romereborn.virginia.edu). It exploits intangible information in order to make a plausible reconstruction of ancient Rome, currently one of the largest virtual models ever developed in the field of cultural heritage.

The Digital Hadrian's Villa Project: Using virtual worlds to control suspected solar alignments

This paper discusses how the Digital Hadrians Villa Project has used virtual world technology to control the validity of a claimed alignment between the suns position at sunset on the summer solstice during the reign of Hadrian (117-138 CE) and the tower structure at Hadrians Villa known as Roccabruna. The conclusion is reached that virtual world technology is usefully applied in investigations of this kind.

Image-based 3D capture of cultural heritage artifacts an experimental study about 3D data quality.

The paper presents an analysis of the 3D data quality generated from small-medium objects by well-known automatic photogrammetry packages based on Structure from Motion (SfM) and Image Matching (IM). The work aims at comparing different shooting configurations and image redundancy, using as high-quality reference the 3D data acquired by triangulation-based laser scanners characterized by a low measurement uncertainty. Two set of tests are presented: i) a laboratory 3D measurement made with the two active and passive approaches, where the image-based 3D acquisition makes use of different camera orientations leading to different image redundancy; ii) a 3D digitization in the field with an industrial laser scanner and two sets of images taken with different overlap levels. The results in the field confirm the relationship between measurement uncertainty and image overlap that emerged in the Lab tests.

Analysis of Classical Greek and Latin Compositional Word-Order Data*

A recent paper by Frischer et al. (forthcoming) examines the position of the direct object and its governing verb in works in Classical Greek and Latin. The paper confirms the SOY ordering expected in texts in Latin, and the S(O)V(O) ordering expected in texts written in Greek. Texts written in Greek by Cassius Dio were found to have a Latinate word-order. However, subsequent research on the statistical analysis used in that paper has resulted in a refinement that will be presented in the present paper. For each of the six ty texts examined, one hundred direct objects were categorised. The knowledge of the total number of direct objects examined conxad strains the data; it is described as being compositional. In this paper we re-examine the data using techniques developed for compositional data analysis. The conclusions of Frischer et a l. are confirmed and new insights into texts by Marcus Aurelius and Plutarch are obtained.

Panel 1: Continuity and Change in University Scholarship

ABSTRACT Information technology developments over the past 3 decades have profoundly influenced university scholarship, but the relationship has been characterized by aspects of both continuity and change. This panel of presentations and ensuing discussion consider ways in which these developments drive changes in scholarly practice and present challenges for research libraries on issues such as interoperability or facilitating access in a networked environment.