Comparison of different digital models of a sustainable bamboo structure using aerial photogrammetry

In eastern countries the use of bamboo as sustainable and local material is becoming a standard. The integration of this environmentally friendly material in complex structure and buildings is appreciated also from an architectural point of view. In this paper a digitalization of a bamboo spatial truss structure using aerial photogrammetry and computer vision is presented. Thanks to the availability of commercial and low-cost UAVs (Unmanned Aerial Vehicles), surveying by means of 3d reconstruction generated by computer vision algorithms low costs application are possible. These tools allow for a quick and effective methodology to acquire image data and reconstruct a detailed 3d model that can be used for structural analysis and maintenance operations. The developed methodology for acquiring data through UAV is introduced, specifying the flight acquisition plan to obtain the images data, and the data processing using structure-from-motion algorithms to provide an accurate 3d-model. Particular attention is focalized on the knots. The accuracy of the measurements is evaluated by comparing results with project drawings. The results highlight the economical and fast applicability of this technology to the survey of spatial truss structures to derive a 3d model, that can be used to investigate the structural health conditions.