Computation of ego-motion and structure from visual and inertial sensors using the vertical cue

The authors develop a method of recovery of some aspects of the 3-D structure and motion of a scene in the case of a virtual moving observer with visual and odometric sensors. This observer attempts to build a 3-D depth and kinematic map of its environment, which can obtain fixed or moving objects. The development and implementation of some layers of a line-segment based module are described to recover ego-motion while building a 3-D map of the environment in which the absolute vertical is taken into account. Given a monocular sequence of images and 2-D-line-segments in this sequence, the goal is to reduce the disparity between two frames in such a way that 3-D vision is simplified, while an initial value for the 3-D rotation is provided. Using the vertical as a basic cue for 3-D-orientation tremendously simplifies and enrichs the structure from motion paradigm, but the usual equations have to be worked out in a different way