The 4D-CH Calw Project - Spatio-temporal Modelling of Photogrammetry and Computer Graphics

The 4D -Cultural Heritage Project takes advance of Imagery from the wild (Internet) and existing repositories to reconstruct 3D Models of Monuments, Places and Landscapes. This method however can not always reproduce a complete dataset of an object since the obliged views are depending on the prominent positions of the recording. We would like to present two different approaches to a work-flow which overcomes this issue through a semi – automated reconstruction as well as the use of simulation with a grammar based modelling. 1. INTRODUCTION TO THE 4D-CH PROJECT The advent of technology in digital cameras and their incorporation into virtually any mobile device has led to an explosion of the number of photographs taken every day. Today, the number of photographs stored online and available freely has reached unprecedented levels. It is estimated that in 2011, there were over 100 billion photographs stored in just one of the major social media sites. This number is growing fast. Moreover, advances in the fields of Photogrammetry and Computer Vision have led to significant breakthroughs such as the Structure from Motion algorithm which creates three-dimensional models of objects using their two-dimensional photographs. The existence of powerful and affordable computational machinery has now made possible not only the reconstruction of complex structures but also entire cities. 2. THE CASE STUDY OF THE CITY OF CALW Within the 4DCH project, the city of Calw has been chosen as a test site for 3D reconstruction where different approaches were applied to model the central square of the settlement in different time settings (see Dieter Fritsch and Michael Klein, 2014). According to the project plan not only the central square of the town, but also the somewhat larger historical settlement core was modeled. The results will be made accessible in an interactive virtual 3D realtime environment, powered by a game engine allowing the user to walk or fly-through the 3D model of the settlement and retrieve additional information on places and buildings on his demand. Further the switch into different time periods of the environment or a building will be possible depending on the accuracy and quantaty of the source material which is necessary to model out the complete set of structures.