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In questo numero di Archeomatica, Luca Papi (CNR) presenta la prima serie tematica dedicata alla presentazione di cinque Laboratori del Consiglio Nazionale delle Ricerche, il grande Ente Pubblico di Ricerca in Italia. Per ciascun laboratorio i direttori saranno chiamati a descrivere le competenze, le attività di ricerca, i progetti, le collaborazioni nazionali e internazionali della struttura di cui sono responsabili. Questa serie di articoli si apre con la presentazione del Visual Computing Lab dell'Istituto di Scienza e Tecnologie dell'Informazione "A. Faedo" (ISTI) di Pisa afferente al Dipartimento di Ingegneria, ICT e Tecnologie per l'Energia e i Trasporti (DIITET) del CNR.

Le tecniche di visualizzazione grafica tridimensionale accoppiate alle più recenti metodiche per il rilievo delle caratteristiche di forma e colore aprono notevoli possibilità di analisi, studio e documentazione nel settore dei Beni Culturali 2. Come emerso dai precedenti contributi è oggi possibile campionare la superficie di un'opera d'arte in modo molto accurato e con una risoluzione spaziale molto alta (si parla in entrambi i casi di valori dell'ordine di pochi micron), ottenendo modelli tridimensionali estremamente fedeli all'originale 3. Inoltre, e' oggi possibile acquisire informazioni sulle modalità con cui la superficie stessa riflette la radiazione luminosa, sia acquisendo la luce riflessa sulle varie bande 4 che rilevando come diverse direzioni di incidenza siano riflesse nelle varie possibili direzioni di riflessione (Bi-directional Reflectance Distribution Function, BRDF). In questa sezione vedremo come tale informazione possa essere integrata e fruita dallo studioso per mezzo di uno strumento di visualizzazione 3D.

CENOBIUM project is a multimedia presentation of Romanesque cloister capitals from the Mediterranean region. High-resolution digital photographs, 3-D models, and panoramas will virtually link the capitals to their original surroundings, thus representing them within their original architectural and conceptual contexts. The cloister of Monreale is the starting point of this project, which combines classical and innovative methods of Art History with the latest in multimedia data technology. The paper describes the different acquisition and documentation; it also outlines the main components of the system which will allow the user to virtually explore the cloister.

Detailed and accurate digital 3D models can be produced with 3D scanning devices, which allow to convert reality in digital form in a cost- and time-effective manner. The capabilities of this technology and the global methodology are presented here in a synthetic manner. Moreover, we focus on the main issues which are preventing its wider use in contemporary applications, such as: the considerable user intervention required, the usually incomplete sampling of the artifact surface and the complexity of the models produced. Another emerging issue is how to support the visual presentation of the models (local or remote) with guaranteed interactive rendering rates. Some practical examples from the results of current projects in the Cultural Heritage field will be shown.

Automatic 3D acquisition devices (often called 3D scanners) allow to build highly accurate models of real 3D objects in a cost- and time-effective manner. We have experimented this technology in a particular application context: the acquisition of Cultural Heritage artifacts. Specific needs of this domain are: medium-high accuracy, easy of use, affordable cost of the scanning device, self-registered acquisition of shape and color data, and finally operational safety for both the operator and the scanned artifacts. According to these requirements, we designed a low-cost 3D scanner based on structured light which adopts a new, versatile colored stripe pattern approach. We present the scanner architecture, the software technologies adopted, and the first results of its use in a project regarding the 3D acquisition of an archeological statue.

The recent evolution of graphics technology has been impressive, and the management of very complex models is now possible on inexpensive platforms. Moreover, automatic scanning devices (often called 3D scanners) allow to build highly accurate models of real 3D objects in a cost- and time-effective manner. This paper discusses some issues in the use of this technology by taking into account a particular application context: the acquisition of Cultural Heritage artifacts. Specific needs of this domain are: a high accuracy, a lower cost of the scanning devices and an improved usability of the data produced. We will present the results of two projects, aimed at: the design of a low-cost scanner based on structured light; the design of a data simplification tool which enables complex dataset visualization on low cost computers.