With these, bundle adjustment
can be initialized from automated image measurements
alone. For example, to work efficiently, coarse estimates for camera
model parameters are also required, e.g., focal length, but most
software will just automatically extract appropriate values from
image file metadata. Thus, 3D models can be effectively constructed
from a wide variety of imagery, with no user intervention (e.g.,
Snavely et al., 2008a, 2008b, 2006). However, the results of such a
3D reconstruction will be in an arbitrary coordinate system so, to
reference to a real-world system, the model needs to be transformed
through the use of some control data. The control requirements
are usually significantly less arduous than for
‘conventional’ photogrammetry, but control data are not necessarily
incorporated throughout model construction and their error
estimates are more weakly integrated