  This work presents and evaluates a novel compact scene representation based
on Stixels that infers geometric and semantic information. Our approach
overcomes the previous rather restrictive geometric assumptions for Stixels by
introducing a novel depth model to account for non-flat roads and slanted
objects. Both semantic and depth cues are used jointly to infer the scene
representation in a sound global energy minimization formulation.
  Furthermore, a novel approximation scheme is introduced in order to
significantly reduce the computational complexity of the Stixel algorithm, and
then achieve real-time computation capabilities. The idea is to first perform
an over-segmentation of the image, discarding the unlikely Stixel cuts, and
apply the algorithm only on the remaining Stixel cuts. This work presents a
novel over-segmentation strategy based on a Fully Convolutional Network (FCN),
which outperforms an approach based on using local extrema of the disparity
map.
  We evaluate the proposed methods in terms of semantic and geometric accuracy
as well as run-time on four publicly available benchmark datasets. Our approach
maintains accuracy on flat road scene datasets while improving substantially on
a novel non-flat road dataset.
