  Boundary detection is essential for a variety of computer vision tasks such
as segmentation and recognition. In this paper we propose a unified formulation
and a novel algorithm that are applicable to the detection of different types
of boundaries, such as intensity edges, occlusion boundaries or object category
specific boundaries. Our formulation leads to a simple method with
state-of-the-art performance and significantly lower computational cost than
existing methods. We evaluate our algorithm on different types of boundaries,
from low-level boundaries extracted in natural images, to occlusion boundaries
obtained using motion cues and RGB-D cameras, to boundaries from
soft-segmentation. We also propose a novel method for figure/ground
soft-segmentation that can be used in conjunction with our boundary detection
method and improve its accuracy at almost no extra computational cost.
