Comparative Analysis of Different UAV-Based Photogrammetric Processes to Improve Product Accuracies

Producing geographic information has become increasingly widespread over the last few years thanks to the development of new sensors, tools and algorithms, easily to be implemented and user friendly. Nevertheless, the accuracy of photogrammetric outcomes, obtained by automated software instructions and the use of un-calibrated cheap sensors, is often unsatisfying. As a consequence, the results accuracy and the potentialities and repeatability of those procedures have to be improved, defining the best workflow to be adopted. In literature, different approaches related to the correct and efficient reduction of geometric errors are available, although, to date, comprehensive method has not yet been defined.