Crowdsource Drone Imagery – A Powerful Source for the 3D Documentation of Cultural Heritage at Risk

Heritage at risk is a terminology used to describe the sites that are highly at risk of being lost as a result of intentional demolition, deterioration, negligence or subject to improper preservation or mistreatment. Iraq is one of the countries that suffered in the last decade from intentional demolition of highly valuable heritage sites and objects. As Iraq gradually recovering from wars and violence with limited resources and budgets, historical and heritage places are still at risk because of neglect, community ignorance, insufficient planning, and military actions. Therefore, in this paper, we propose the idea of using crowdsource drone images and videos which are captured by amateurs for the documentation of heritage sites. Those crowdsource images represent a great source of data that does not require significant financial and hard labor resources. It should be noted that there is no guarantee to have the captured data being sufficient for the 3D documentation and therefore it is proposed to integrate, when possible, multiple captured crowdsource data to ensure complete documentation.In this paper, three Iraqi historical sites are 3D reconstructed using crowdsource drone videos, namely: Rabban Hormizd Monastery (AD 640), Taq Kasra (AD 242 to 272), and the Great Mosque of Samarra (AD 849–851). The experiments showed a successful 3D modeling of the three mentioned heritage objects using the crowdsource drone video images despite being captured for non-3D purposes which require high expertise and planning. With the absence of highly accurate reference data, the overall relative accuracy of the object’s dimensions is found to be less than 1 m.