Accurate Modelling of Roman Lamps in Conimbriga using High Dynamic Range

Abstract

The Human Visual System has a remarkable ability to acquire colour and contrast of all the things that surround us. This is particularly evident in extreme lighting conditions such as bright light or dark environments. However, it is simply not possible to represent such a range of lighting on a typical display today. This is about to change. The field of High Dynamic Range (HDR) imagery allows us to capture and display the full range of human vision. The use of technologies in the preservation and dissemination of cultural heritage can play an important role in the representation and interpretation of our past legacy. A major field of application is virtual reconstructions of ancient historical environments. In this domain, the way we see such (reconstructed) environments is particularly important in order to establish a correct interpretation of that historical setting. In this paper we present a case study of the reconstruction of a Roman site. We generate HDR images of mosaics and frescoes from one of the most impressive monuments in the ruins of Conimbriga, Portugal, an ancient city of the Roman Empire. We show that the HDR viewing paradigm is well suited for archaeological interpretation, since its high contrast and chromaticity can disclose and present us an enhanced viewing experience, closer to how the artefacts may have been perceived in the past. To achieve the requisite level of precision, in addition to a precise geometric 3D model, it is crucial to integrate in the virtual simulation authentic physical data of the light used in the period under consideration. Thereby in order to create a realistic physical based environment we use in our lighting simulations real data obtained from Roman luminaries of that time.