Acquisition, Representation, Processing and Display of Digital Heritage Sites

This chapter presents salient aspects of the research undertaken on the project Acquisition, Representation, Processing and Display of Digital Heritage Sites. The main objective of the project was to create algorithms and techniques to acquire a three-dimensional digital replica of complex structures spread over a large area. The techniques developed are applied to Hampi, a world heritage site. In addition to acquiring the geometry and surface properties, we also research efficient representation and visualisation of this data and provide tools and methods for users to experience the captured models, to virtual walk-through and explore the digital recreations. For the acquisition, we rely on multimodal input using technologies like laser scanners, colour cameras and depth sensors. We align and fuse geometric constructions from different modalities through a step of registration. We have extended structure from motion (SfM), a state-of-the-art approach for multi-view 3D reconstruction from images and developed techniques for large-scale (relatively) sparse geometric constructions and simultaneously dense reconstructions of smaller parts. We also provide ability to generate high-resolution point cloud from the point cloud obtained from depth camera Kinect by using additional high definition cameras. We also explore efficient visualisation of large models with augmented reality and user experience authoring. Hampi has been chosen as a test bench for developing our techniques. Within Hampi, we concentrate on Vittala Temple Complex, and demonstrate our techniques on it. The project has greatly benefitted from the collaboration from other partner institutes especially BVBCET, NID, NIAS, IIT Bombay, IIT Madras and IIIT Hyderabad and IISc Bangalore.