  We propose a new bottom-up method for multi-person 2D human pose estimation
that is particularly well suited for urban mobility such as self-driving cars
and delivery robots. The new method, PifPaf, uses a Part Intensity Field (PIF)
to localize body parts and a Part Association Field (PAF) to associate body
parts with each other to form full human poses. Our method outperforms previous
methods at low resolution and in crowded, cluttered and occluded scenes thanks
to (i) our new composite field PAF encoding fine-grained information and (ii)
the choice of Laplace loss for regressions which incorporates a notion of
uncertainty. Our architecture is based on a fully convolutional, single-shot,
box-free design. We perform on par with the existing state-of-the-art bottom-up
method on the standard COCO keypoint task and produce state-of-the-art results
on a modified COCO keypoint task for the transportation domain.
