2016 Volume 69 Issue 4 Pages 297-309
With the spread of small unmanned aerial vehicle (UAV) equipped with a digital camera (UAS: unmanned aerial system), it has been facilitated to acquire multi-view aerial images. Whereas, the technique of Structure-from-Motion Multi-View Stereo photogrammetry (SfM-MVS) has also been developed to enable the creation of three-dimensional models of targets including landforms and objects on the land surface from a large number of stereo-pair images. The combined use of these UAS and SfM, i.e., the photogrammetry of low-altitude aerial images, has enhanced topographical measurements of landforms and ground objects in a variety of fields. In this paper, we outline the overviews of UAS as a platform and SfM as measurement technique, and then introduce some examples of applied topographic measurements by SfM based on the aerial imaging with UAS. Thus, the low price and easy operation of UAS-SfM technique have allowed rapid acquisition of high-definition three-dimensional data of landforms and ground objects based on the aerial measurement, as well as the change detection of such objects, for any researchers and practitioners. Therefore the method has a large potential to be effectively used as the basic data acquisition and analysis for geophysical surveys. In addition, it is desirable to perform such high-definition topographic measurements with careful examination of optimized resolution and reasonable accuracy by the scale and the purpose of the phenomenon of interest.
