Sebastian Nowozin, Carsten Rother, Shai Bagon, Toby Sharp, Bangpeng Yao, and Pushmeet Kohli
2011
This paper introduces a new formulation for discrete image
labeling tasks, the Decision Tree Field (DTF), that combines
and generalizes random forests and conditional random
fields (CRF) which have been widely used in computer
vision. In a typical CRF model the unary potentials are derived
from sophisticated random forest or boosting based
classifiers, however, the pairwise potentials are assumed to
(1) have a simple parametric form with a pre-specified and
fixed dependence on the image data, and (2) to be defined on
the basis of a small and fixed neighborhood. In contrast, in
DTF, local interactions between multiple variables are determined
by means of decision trees evaluated on the image
data, allowing the interactions to be adapted to the image
content. This results in powerful graphical models which
are able to represent complex label structure. Our key technical
contribution is to show that the DTF model can be
trained efficiently and jointly using a convex approximate
likelihood function, enabling us to learn over a million free
model parameters. We show experimentally that for applications
which have a rich and complex label structure, our
model achieves excellent results.
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In ICCV
| Type | Inproceedings |