Image parsing remains difficult due to the need to combine
local and contextual information when labeling a
scene. We approach this problem by using the epitome as a
prior over label configurations. Several properties make it
suited to this task. First, it allows a condensed patch-based
representation. Second, efficient E-M based learning and
inference algorithms can be used. Third, non-stationarity is
easily incorporated. We consider three existing priors, and
show how each can be extended using the epitome. The simplest
prior assumes patches of labels are drawn independently
from either a mixture model or an epitome. Next we
investigate a ‘conditional epitome’ model, which substitutes
an epitome for a conditional mixture model. Finally, we develop
an ‘epitome tree’ model, which combines the epitome
with a tree structured belief network prior. Each model is
combined with a per-pixel classifier to perform segmentation.
In each case, the epitomized form of the pr...
Jonathan Warrell, Simon J. D. Prince, Alastair P.