All the graphical documents produced by Dogram are obtained from photographs by means of dense volumetric reconstructions of the original items. Image-based 3D reconstruction photogrammetric methods are combined with additional processing of the environmental light and their influence on the surface of the item. This allows to reproduce realistic-looking virtual objects and scenes with an enriched surface appearance model which reacts properly to observer motion and dynamic re-illumination introducing the Realistic Virtual Replicas.
Starting only from conventional photographs, the resulting models extend the existing capabilities of 3D scanning and image-based modelling methods. The resulting realistic visualization of the digital model reproduces not only the geometry and photographic texture under fixed environmental illumination. It also reproduces the variable optical response of the surfaces when either observation or light incidence angles change. This is necessary to properly reproduce the active changes in appearance of the surface when there are movements in the object, the point of view or the lights in the scene (dynamic re-illumination)
The digitalization procedures used by Dogram are capable of simultaneously determine shape and appearance of the surface and environmental illumination, starting only from conventional photographs taken under variable illumination (including natural light). This method is proven practical and flexible enough to be used successfully in a variety of situations and environments, such as museum items, outdoor sculptures or building façades.
Two practical examples illustrate this technique:
The Lady of Elche. Departing from an archived set of photographs, we will show a highly detailed 3D model that can be re-lighted and rendered in real-time. This configures a documentation procedure that can be applied on site, in very short times and using only portable photographic equipment.
La Regenta. It is a example of the capture on larger architectural elements, with uncontrolled (yet still variable) illumination from outdoor environments and on other challenging items with difficult surfaces such as the brass sculpture of La Regenta, where proper mapping of surface reflection and environmental light are fundamental to provide a good visualization experience.
The Realistic Virtual Replicas are a important development to spread the cultural heritage:
- Creating virtual museums by web application.
- Making Realistic Replicas with great detail.
- Installing the Realistic Virtual Replicas in newsstand which are designed to spread the cultural heritage.
In addition to this, the Realistic Virtual Replicas provide a working tool for technicians who take responsibility for conservation and restoration of cultural heritage.