In structure-from-motion with a single camera it is well
known that the scene can be only recovered up to a scale. In
order to compute the absolute scale, one needs to know the
baseline of the camera motion or the dimension of at least
one element in the scene. In this paper, we show that there
exists a class of structure-from-motion problems where it is
possible to compute the absolute scale completely automatically
without using this knowledge, that is, when the camera
is mounted on wheeled vehicles (e.g. cars, bikes, or mobile
robots). The construction of these vehicles puts interesting
constraints on the camera motion, which are known as
“nonholonomic constraints”. The interesting case is when
the camera has an offset to the vehicle’s center of motion.
We show that by just knowing this offset, the absolute scale
can be computed with a good accuracy when the vehicle
turns. We give a mathematical derivation and provide experimental
results on both simulated and ...