191 research outputs found
Zero Shot Recognition with Unreliable Attributes
In principle, zero-shot learning makes it possible to train a recognition
model simply by specifying the category's attributes. For example, with
classifiers for generic attributes like \emph{striped} and \emph{four-legged},
one can construct a classifier for the zebra category by enumerating which
properties it possesses---even without providing zebra training images. In
practice, however, the standard zero-shot paradigm suffers because attribute
predictions in novel images are hard to get right. We propose a novel random
forest approach to train zero-shot models that explicitly accounts for the
unreliability of attribute predictions. By leveraging statistics about each
attribute's error tendencies, our method obtains more robust discriminative
models for the unseen classes. We further devise extensions to handle the
few-shot scenario and unreliable attribute descriptions. On three datasets, we
demonstrate the benefit for visual category learning with zero or few training
examples, a critical domain for rare categories or categories defined on the
fly.Comment: NIPS 201
Slow and steady feature analysis: higher order temporal coherence in video
How can unlabeled video augment visual learning? Existing methods perform
"slow" feature analysis, encouraging the representations of temporally close
frames to exhibit only small differences. While this standard approach captures
the fact that high-level visual signals change slowly over time, it fails to
capture *how* the visual content changes. We propose to generalize slow feature
analysis to "steady" feature analysis. The key idea is to impose a prior that
higher order derivatives in the learned feature space must be small. To this
end, we train a convolutional neural network with a regularizer on tuples of
sequential frames from unlabeled video. It encourages feature changes over time
to be smooth, i.e., similar to the most recent changes. Using five diverse
datasets, including unlabeled YouTube and KITTI videos, we demonstrate our
method's impact on object, scene, and action recognition tasks. We further show
that our features learned from unlabeled video can even surpass a standard
heavily supervised pretraining approach.Comment: in Computer Vision and Pattern Recognition (CVPR) 2016, Las Vegas,
NV, June 201
Learning to Look Around: Intelligently Exploring Unseen Environments for Unknown Tasks
It is common to implicitly assume access to intelligently captured inputs
(e.g., photos from a human photographer), yet autonomously capturing good
observations is itself a major challenge. We address the problem of learning to
look around: if a visual agent has the ability to voluntarily acquire new views
to observe its environment, how can it learn efficient exploratory behaviors to
acquire informative observations? We propose a reinforcement learning solution,
where the agent is rewarded for actions that reduce its uncertainty about the
unobserved portions of its environment. Based on this principle, we develop a
recurrent neural network-based approach to perform active completion of
panoramic natural scenes and 3D object shapes. Crucially, the learned policies
are not tied to any recognition task nor to the particular semantic content
seen during training. As a result, 1) the learned "look around" behavior is
relevant even for new tasks in unseen environments, and 2) training data
acquisition involves no manual labeling. Through tests in diverse settings, we
demonstrate that our approach learns useful generic policies that transfer to
new unseen tasks and environments. Completion episodes are shown at
https://goo.gl/BgWX3W
Creating Capsule Wardrobes from Fashion Images
We propose to automatically create capsule wardrobes. Given an inventory of
candidate garments and accessories, the algorithm must assemble a minimal set
of items that provides maximal mix-and-match outfits. We pose the task as a
subset selection problem. To permit efficient subset selection over the space
of all outfit combinations, we develop submodular objective functions capturing
the key ingredients of visual compatibility, versatility, and user-specific
preference. Since adding garments to a capsule only expands its possible
outfits, we devise an iterative approach to allow near-optimal submodular
function maximization. Finally, we present an unsupervised approach to learn
visual compatibility from "in the wild" full body outfit photos; the
compatibility metric translates well to cleaner catalog photos and improves
over existing methods. Our results on thousands of pieces from popular fashion
websites show that automatic capsule creation has potential to mimic skilled
fashionistas in assembling flexible wardrobes, while being significantly more
scalable.Comment: Accepted to CVPR 201
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