Can we discover common object shapes within unlabeled
multi-category collections of images? While often a critical
cue at the category-level, contour matches can be difficult
to isolate reliably from edge clutter—even within labeled
images from a known class, let alone unlabeled examples.
We propose a shape discovery method in which local appearance
(patch) matches serve to anchor the surrounding
edge fragments, yielding a more reliable affinity function
for images that accounts for both shape and appearance.
Spectral clustering from the initial affinities provides candidate
object clusters. Then, we compute the within-cluster
match patterns to discern foreground edges from clutter, attributing
higher weight to edges more likely to belong to
a common object. In addition to discovering the object
contours in each image, we show how to summarize what
is found with prototypical shapes. Our results on benchmark
datasets demonstrate the approach can successfully
discover ...