806 research outputs found
Generating Visual Representations for Zero-Shot Classification
This paper addresses the task of learning an image clas-sifier when some
categories are defined by semantic descriptions only (e.g. visual attributes)
while the others are defined by exemplar images as well. This task is often
referred to as the Zero-Shot classification task (ZSC). Most of the previous
methods rely on learning a common embedding space allowing to compare visual
features of unknown categories with semantic descriptions. This paper argues
that these approaches are limited as i) efficient discrimi-native classifiers
can't be used ii) classification tasks with seen and unseen categories
(Generalized Zero-Shot Classification or GZSC) can't be addressed efficiently.
In contrast , this paper suggests to address ZSC and GZSC by i) learning a
conditional generator using seen classes ii) generate artificial training
examples for the categories without exemplars. ZSC is then turned into a
standard supervised learning problem. Experiments with 4 generative models and
5 datasets experimentally validate the approach, giving state-of-the-art
results on both ZSC and GZSC
Expanded Parts Model for Semantic Description of Humans in Still Images
We introduce an Expanded Parts Model (EPM) for recognizing human attributes
(e.g. young, short hair, wearing suit) and actions (e.g. running, jumping) in
still images. An EPM is a collection of part templates which are learnt
discriminatively to explain specific scale-space regions in the images (in
human centric coordinates). This is in contrast to current models which consist
of a relatively few (i.e. a mixture of) 'average' templates. EPM uses only a
subset of the parts to score an image and scores the image sparsely in space,
i.e. it ignores redundant and random background in an image. To learn our
model, we propose an algorithm which automatically mines parts and learns
corresponding discriminative templates together with their respective locations
from a large number of candidate parts. We validate our method on three recent
challenging datasets of human attributes and actions. We obtain convincing
qualitative and state-of-the-art quantitative results on the three datasets.Comment: Accepted for publication in IEEE Transactions on Pattern Analysis and
Machine Intelligence (TPAMI
Improving Semantic Embedding Consistency by Metric Learning for Zero-Shot Classification
This paper addresses the task of zero-shot image classification. The key
contribution of the proposed approach is to control the semantic embedding of
images -- one of the main ingredients of zero-shot learning -- by formulating
it as a metric learning problem. The optimized empirical criterion associates
two types of sub-task constraints: metric discriminating capacity and accurate
attribute prediction. This results in a novel expression of zero-shot learning
not requiring the notion of class in the training phase: only pairs of
image/attributes, augmented with a consistency indicator, are given as ground
truth. At test time, the learned model can predict the consistency of a test
image with a given set of attributes , allowing flexible ways to produce
recognition inferences. Despite its simplicity, the proposed approach gives
state-of-the-art results on four challenging datasets used for zero-shot
recognition evaluation.Comment: in ECCV 2016, Oct 2016, amsterdam, Netherlands. 201
The Many Moods of Emotion
This paper presents a novel approach to the facial expression generation
problem. Building upon the assumption of the psychological community that
emotion is intrinsically continuous, we first design our own continuous emotion
representation with a 3-dimensional latent space issued from a neural network
trained on discrete emotion classification. The so-obtained representation can
be used to annotate large in the wild datasets and later used to trained a
Generative Adversarial Network. We first show that our model is able to map
back to discrete emotion classes with a objectively and subjectively better
quality of the images than usual discrete approaches. But also that we are able
to pave the larger space of possible facial expressions, generating the many
moods of emotion. Moreover, two axis in this space may be found to generate
similar expression changes as in traditional continuous representations such as
arousal-valence. Finally we show from visual interpretation, that the third
remaining dimension is highly related to the well-known dominance dimension
from psychology
CAKE: Compact and Accurate K-dimensional representation of Emotion
Numerous models describing the human emotional states have been built by the
psychology community. Alongside, Deep Neural Networks (DNN) are reaching
excellent performances and are becoming interesting features extraction tools
in many computer vision tasks.Inspired by works from the psychology community,
we first study the link between the compact two-dimensional representation of
the emotion known as arousal-valence, and discrete emotion classes (e.g. anger,
happiness, sadness, etc.) used in the computer vision community. It enables to
assess the benefits -- in terms of discrete emotion inference -- of adding an
extra dimension to arousal-valence (usually named dominance). Building on these
observations, we propose CAKE, a 3-dimensional representation of emotion
learned in a multi-domain fashion, achieving accurate emotion recognition on
several public datasets. Moreover, we visualize how emotions boundaries are
organized inside DNN representations and show that DNNs are implicitly learning
arousal-valence-like descriptions of emotions. Finally, we use the CAKE
representation to compare the quality of the annotations of different public
datasets
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