Depending on the application, the burden of measuring GCP can
be traded against a lower resulting accuracy. This suites various
needs in terms of accuracy, time to result and cost. Growers
or people engaged in field mission planning for instance may be
interested obtain a quick survey in the form of a georeferenced
orthomosaic produced fully automatically within minutes. We
show that the accuracy without GCP lies in the range of 2m for
low altitude imagery. With just a little bit more of human intervention,
i.e. the designation of a couple of GCPs in the images,
an accuracy of 0.05-0.2m can be achieved. This accuracy largely
depends on the ground resolution of the original images as will
be shown later on.
To the best of our knowledge, this paper presents the first demonstration
that the combination of ultra-light UAV imagery and automated
processing is possible and yields accurate results, comparable
to the ones obtained with traditional photogrammetric
systems mounted on airplanes. The main issue to achieve this
is the imprecise measurements for the location and orientation
of the individual images (Eisenbeiss and W.Stempfhuber, 2009).
Recent techniques rooted in computer vision, their fast and scalable
implementation and the robust integration to photogrammetric
techniques are the main key to circumvent the lack of precise
sensor information. The presented approach opens the door to a
wide range of new applications and users which can now access
geographic informations at an affordable cost and without any
knowledge in photogrammetry. The temporal (4-dimensional)