Multi-Camera Workflow Applied to a Cultural Heritage Building: Alhambra’s Torre de la Cautiva from the Inside

Abstract

It is increasingly necessary to generate accessible and navigable digital representations of historical or heritage buildings. This article explains the workflow that was applied to create such a digital component for one of the least accessible areas of the Alhambra palace in Granada, the so-called Torre de la Cautiva (Tower of the Captive). The main goal of this process was to create affordable, photorealistic 3D models that contribute to the dissemination of cultural heritage, the decision making for its conservation and restoration, and public engagement and entertainment. With enough preparation, the time spent gathering data following a Structure from Motion (SfM) approach can be significantly reduced by using a multi-camera (low cost DSLR) photogrammetric strategy. Without the possibility of artificial lighting, it was essential to use RAW images and calibrate the color in the scene for material and texture characterization. Through processing, the amount of data was reduced by optimizing the model’s topology. Thus, a photorealistic result was obtained that could be managed and visualized in immersive Visual Reality (VR) environments, simulating different historical periods and environmental and lighting conditions. The potential of this method allows, with slight modifications, the creation of HBIMs and the adaptation to VR systems development, whose current visualization quality is below the resolution of actionable models in rendering engines.