Structure from motion

In visual perception, the problem of SfM is to find an algorithm by which biological creatures perform this task.

[5] Another type of feature recently made practical for structure from motion are general curves (e.g., locally an edge with gradients in one direction), part of a technology known as pointless SfM,[7][8] useful when point features are insufficient, common in man-made environments.

A somewhat intermediate approach is out-of-core SfM, where several partial reconstructions are computed that are then integrated into a global solution.

Structure-from-motion photogrammetry with multi-view stereo provides hyperscale landform models using images acquired from a range of digital cameras and optionally a network of ground control points.

The technique is not limited in temporal frequency and can provide point cloud data comparable in density and accuracy to those generated by terrestrial and airborne laser scanning at a fraction of the cost.

[17][18][19] Structure from motion is also useful in remote or rugged environments where terrestrial laser scanning is limited by equipment portability and airborne laser scanning is limited by terrain roughness causing loss of data and image foreshortening.

[27] SfM has been also successfully applied for the assessment of changes[28] and large wood accumulation volume[29] and porosity[30] in fluvial systems, the characterization of rock masses through the determination of some properties as the orientation, persistence, etc.

Under this point of view, SfM is used in order to properly estimate situations as well as planning and maintenance efforts and costs, control and restoration.

Because serious constraints often exist connected to the accessibility of the site and impossibility to install invasive surveying pillars that did not permit the use of traditional surveying routines (like total stations), SfM provides a non-invasive approach for the structure, without the direct interaction between the structure and any operator.

[35] Furthermore, structure-from-motion photogrammetry represents a non-invasive, highly flexible and low-cost methodology to digitalize historical documents.