Image-based Modeling allows for the three-dimensional representation of objects from many two-dimensional images. The 3D models are created by using multiple images. Structure from Motion (SfM) is such an approach to create a three-dimensional reconstruction of an object using images created in an often circular dome-like motion around the object.
A historical precursor to this approach is stereoscopy, which has enabled spatial viewing in 2D images since 1838. Here, two slightly different images of an object from slightly offset perspectives are used to simulate spatial perception. Photogrammetry, especially 3D photogrammetry, builds on this stereoscopy. However, it does not only use two images, but many, in order to create precise three-dimensional models. By combining many images from different perspectives, dense point clouds are generated, which allow for a detailed 3D model of an object or landscape.
In archaeology, 3D photogrammetry has also found application. A popular term for this process is "Structure from Motion" (SfM). This is an approach in computer vision where the 3D structure of a scene and the camera positions are reconstructed from a sequence of images taken from different viewpoints. The key aspect of SfM is motion: the relative movement between camera positions is used to extract depth information about the scene (Nyimbili et al. 2016).
In summary, one can say that Structure from Motion is a specific technique within the broader field of image-based modeling. While SfM focuses on the reconstruction of 3D structures from motion, image-based modeling more generally deals with the creation of 3D models from images, with SfM being one of many possible approaches (Doneaus et al. 2011).
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