From reviewing the paper The Untapped Potential of Low Cost Photogrammery in Community-Based Archaeology, it was easy to see that photogrammetry can be used as an alternative to high resolution surveying with high costs.
Traditional softcopy photogrammetric methods require the 3-D location and pose of the camera(s), or the 3-D location of ground control points to be known to facilitate scene triangulation and reconstruction. In contrast, the SfM method solves the camera pose and scene geometry simultaneously and automatically, using a highly redundant bundle adjustment based on matching features in multiple overlapping, offset images [Westoby et al 2012].
Structure from motion is the geometry of creating 3D models from 2D images. If you are interested in the maths behind SfM, visit Prof. Rob Fergus’s lecture notes on Computer Vision, or geometric vision, in particular Lecture 6 on Multiview Stereo & Structure from Motion. It is quite interesting to see the process. Thankfully, to Wu Changchang, we don’t need to understand the mathematics behind how Structure from Motion works, to be able to use it. In his post-doc year at University of Washington Seattle, he developed Visual SfM.
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