An On-Site Presentation of Invisible Prehistoric Landscapes Article - PDF document

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/312480749 An On-Site Presentation of Invisible Prehistoric Landscapes Article in Internet Archaeology · March 2017 DOI: 10.11141/ia.43.13 CITATIONS READS 5 372 2 authors: Jiri Unger Petr Kv ě tina The Czech Academy of Sciences The Czech Academy of Sciences 4 PUBLICATIONS 13 CITATIONS 40 PUBLICATIONS 129 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Variability of Neolithic pottery technology as a marker of social identity View project All content following this page was uploaded by Petr Kv ě tina on 02 October 2017. The user has requested enhancement of the downloaded file.

An On-Site Presentation of Invisible Prehistoric Landscapes. Unger a... http://intarch.ac.uk/journal/issue43/13/13.html CONTENTS SUMMARY ISSUE HOME An On-Site Presentation of Invisible Prehistoric Landscapes Jiri Unger and Petr Kvetina Cite this as : Unger , J. and Kvetina, P . 2017 An On-Site Presentation of Invisible Prehistoric Landscapes, Internet Archaeology 43. https://doi.org/10.11141/ia.43.13 1. Introduction The aim of this article is to demonstrate the opportunities for virtual and augmented presentation of prehistoric sites in situ where there is neither preserved construction nor any relics of the original landscape. Such sites usually meet with indifference both from the general public and institutions that are involved in the preservation of historic monuments. Both virtual reality (VR) and augmented reality (AR) have proven to be tools that have the potential both to grasp the invisible and to describe what has disappeared. Based on the examples of the Neolithic sites at Bylany near Kutna Hora and Prague-Vinor and at the Bronze Age site at Zalezlice in the Czech Republic, we have demonstrated the potential for digital heritage management. Such terms as 'virtual' or 'augmented reality' no longer refer to a million light-years away science-fiction concepts, but instead define a new tool for public archaeology and this article discusses its utilisation for in situ presentation of archaeological sites. The very rapid development of information technology, internet access and the overwhelming scale of the adoption of computer technology in recent years have enabled developments in how archaeological features are presented and reconstructed (Kvetina et al . 2015). However, on-site virtual presentation has very demanding requirements and possible 1 z 12 19.9.2017 9:26

An On-Site Presentation of Invisible Prehistoric Landscapes. Unger a... http://intarch.ac.uk/journal/issue43/13/13.html solutions still need to take into account technical limits. 2. Background of using Augmented Reality on Archaeological Sites During the last decade several systems and frameworks have been developed and tested to present 3D reconstructions of archaeological objects directly on-site through the application of virtual and augmented reality. So far, the AR applications that have been introduced use two basic techniques, overlapping digital and real data technology. The first and most widely used method is referred to as a marker-based method (Figure 1), whereby the virtual data are linked to two-dimensional images or in some cases three-dimensional objects (Kvetina et al . 2015, 13-14). The second method works without utilising these auxiliary markers, instead using optical tracking to place data in the virtual environment, i.e. the use of specific recognisable landmarks that are associated with a certain location. A set of reference images is selected for every point with AR, and live video is captured and compared to all the reference images in a database for the associated location, and when a match is detected the desired virtual visualisations will appear on the display (Zarzycki 2015). Figure 1: The most simple mobile application using marker based AR (scan the QR code and download the app on Google Play) The first pioneering project was Archeoguide, which in 2005 tried to develop an Augmented Reality system that would enable visitors to view a computer-generated reconstruction of ancient Olympia without cutting them off from the real surroundings of the site (Vlahakis et al . 2001). Visitors were provided with a portable computer with sufficient hard-disk space, linked to a close-view head-mounted display, an additional mounted camera and other peripheral devices such as a GPS receiver or a digital compass for orientation and positioning and an image-based tracking system. Another initial attempt related to the ancient Roman city of Pompeii, where the Lifeplus project used AR to bring scenes from old frescoes back to life (Wolfenstetter 2007). Both projects used a hybrid-tracking module involving DGPS, a compass and video tracking the exact positioning and orientation of the 3D reconstructions, and animations 2 z 12 19.9.2017 9:26

An On-Site Presentation of Invisible Prehistoric Landscapes. Unger a... http://intarch.ac.uk/journal/issue43/13/13.html displayed in AR were achieved. The exact optical position tracking without markers was accomplished by comparing the reference images that had been loaded from the central server with the GPS and the compass data (Wolfenstetter 2007, 13). These early mobile systems required the user to wear an entire set of hardware devices including cameras, electronic compasses and small laptops, which made the whole system uncomfortable and difficult to share with the wider public. The new and widely expanded range of portable devices with high-quality sensors including GPS, a compass, an accelerometer and a gyroscope, opens up a whole new range of options for presenting archaeological data and they are well suited for the augmented reality systems. Nevertheless, the most recent research projects that offer several mobile solutions are still unable to visualise outdoor AR 3D models fully (Murru et al . 2013). Markerless optical camera-tracking is a complex task, so for real-time application it is abrupt and unpredictable. There are other problems with the tracking system, leading to issues with positioning and the direction of the view (Noh et al . 2009, 53), while none of the available systems are appropriate for outdoor use without the adequate precision that Archeoguide had, thanks to its specific instrumentation. A project that used AR tracking to visualise the Middle Stoa in the ancient agora of Athens used a Sony VAIO Tap 11 tablet PC with a camera; the authors noticed that the application would need to be improved in terms of speed for rendering huge and detailed 3D models (Verykokou et al . 2014). The remaining obstacles include limited computational performance for optical tracking and the inaccuracy of the GPS in mobile devices, which can be metres out. This may not matter for applications that provide data overlays of supplementary information for physical objects that are perfectly visible with the naked eye, but for placing archaeological/historical buildings in their surroundings, it has a significant impact. One solution would be to make use of the simpler AR marker-based methods; however, at most cultural heritage sites the installation of artificial optical markers is absolutely impossible, which makes landmark tracking the only possible option available (Wolfenstetter 2007, 9). In fact most of the tracking systems that have been used to serve AR must be hybrid systems (Gao 2008), combining the advantages of several technologies (Wifi spots, eBeacons etc.). 3 z 12 19.9.2017 9:26