3D Digitisation of Large-Scale Unstructured Great Wall Heritage Sites by a Small Unmanned Helicopter

3D Digitisation of Large-Scale Unstructured Great Wall Heritage Sites by a Small Unmanned Helicopter

Blog Article

The ancient Great Wall of China has long suffered from damage due to natural factors and human activities.A small low-cost unmanned helicopter system with a laser scanner and a digital camera is developed to efficiently visualize the status of the huge Great Wall area.The goal of the system is to achieve 3D digitisation of the large-scale Great Wall using a combination of fly-hover-scan and flying-scan modes.However, pose uncertainties of the unmanned helicopter could cause mismatching among point clouds Trail Cans acquired by each hovering-scan.This problem would become more severe as the target area becomes larger and more unstructured.

Therefore, a hierarchical optimization framework is Pitcher proposed in this paper to achieve 3D digitisation of the large-scale unstructured Great Wall with unpredictable pose uncertainties of the unmanned helicopter.In this framework, different optimization methodologies are proposed for the fly-hover-scan and flying-scan modes, respectively, because different scan modes would result in different features of point clouds.Moreover, a user-friendly interface based on WebGL has been developed for 3D model visualization and comparison.Experimental results demonstrate the feasibility of the proposed framework for 3D digitisation of the Great Wall segments.