  Recent research has highlighted the utility of Planar Parallax Geometry in
monocular depth estimation. However, its potential has yet to be fully realized
because networks rely heavily on appearance for depth prediction. Our in-depth
analysis reveals that utilizing flow-pretrain can optimize the network's usage
of consecutive frame modeling, leading to substantial performance enhancement.
Additionally, we propose Planar Position Embedding (PPE) to handle dynamic
objects that defy static scene assumptions and to tackle slope variations that
are challenging to differentiate. Comprehensive experiments on autonomous
driving datasets, namely KITTI and the Waymo Open Dataset (WOD), prove that our
Planar Parallax Network (PPNet) significantly surpasses existing learning-based
methods in performance.
