  The detection of polylines in images is usually either bound to branchless
polylines or formulated in a recurrent way, prohibiting their use in real-time
systems.
  We propose an approach that transfers the idea of single shot object
detection. Reformulating the problem of polyline detection as bottom-up
composition of small line segments allows to detect bounded, dashed and
continuous polylines with a single head. This has several major advantages over
previous methods. Not only is the method at 187 fps more than suited for
real-time applications with virtually any restriction on the shapes of the
detected polylines. By predicting multiple line segments for each spatial cell,
even branching or crossing polylines can be detected.
  We evaluate our approach on three different applications for road marking,
lane border and center line detection. Hereby, we demonstrate the ability to
generalize to different domains as well as both implicit and explicit polyline
detection tasks.
