  This paper revisits the problem of continuous-time structure from motion, and
introduces a number of extensions that improve convergence and efficiency. The
formulation with a $\mathcal{C}^2$-continuous spline for the trajectory
naturally incorporates inertial measurements, as derivatives of the sought
trajectory. We analyse the behaviour of split interpolation on $\mathbb{SO}(3)$
and on $\mathbb{R}^3$, and a joint interpolation on $\mathbb{SE}(3)$, and show
that the latter implicitly couples the direction of translation and rotation.
Such an assumption can make good sense for a camera mounted on a robot arm, but
not for hand-held or body-mounted cameras. Our experiments show that split
interpolation on $\mathbb{SO}(3)$ and on $\mathbb{R}^3$ is preferable over
$\mathbb{SE}(3)$ interpolation in all tested cases. Finally, we investigate the
problem of landmark reprojection on rolling shutter cameras, and show that the
tested reprojection methods give similar quality, while their computational
load varies by a factor of 2.
