165 research outputs found
Deeper, Broader and Artier Domain Generalization
The problem of domain generalization is to learn from multiple training
domains, and extract a domain-agnostic model that can then be applied to an
unseen domain. Domain generalization (DG) has a clear motivation in contexts
where there are target domains with distinct characteristics, yet sparse data
for training. For example recognition in sketch images, which are distinctly
more abstract and rarer than photos. Nevertheless, DG methods have primarily
been evaluated on photo-only benchmarks focusing on alleviating the dataset
bias where both problems of domain distinctiveness and data sparsity can be
minimal. We argue that these benchmarks are overly straightforward, and show
that simple deep learning baselines perform surprisingly well on them. In this
paper, we make two main contributions: Firstly, we build upon the favorable
domain shift-robust properties of deep learning methods, and develop a low-rank
parameterized CNN model for end-to-end DG learning. Secondly, we develop a DG
benchmark dataset covering photo, sketch, cartoon and painting domains. This is
both more practically relevant, and harder (bigger domain shift) than existing
benchmarks. The results show that our method outperforms existing DG
alternatives, and our dataset provides a more significant DG challenge to drive
future research.Comment: 9 pages, 4 figures, ICCV 201
Multi-component Image Translation for Deep Domain Generalization
Domain adaption (DA) and domain generalization (DG) are two closely related
methods which are both concerned with the task of assigning labels to an
unlabeled data set. The only dissimilarity between these approaches is that DA
can access the target data during the training phase, while the target data is
totally unseen during the training phase in DG. The task of DG is challenging
as we have no earlier knowledge of the target samples. If DA methods are
applied directly to DG by a simple exclusion of the target data from training,
poor performance will result for a given task. In this paper, we tackle the
domain generalization challenge in two ways. In our first approach, we propose
a novel deep domain generalization architecture utilizing synthetic data
generated by a Generative Adversarial Network (GAN). The discrepancy between
the generated images and synthetic images is minimized using existing domain
discrepancy metrics such as maximum mean discrepancy or correlation alignment.
In our second approach, we introduce a protocol for applying DA methods to a DG
scenario by excluding the target data from the training phase, splitting the
source data to training and validation parts, and treating the validation data
as target data for DA. We conduct extensive experiments on four cross-domain
benchmark datasets. Experimental results signify our proposed model outperforms
the current state-of-the-art methods for DG.Comment: Accepted in WACV 201
Best Sources Forward: Domain Generalization through Source-Specific Nets
A long standing problem in visual object categorization is the ability of algorithms to generalize across different testing conditions. The problem has been formalized as a covariate shift among the probability distributions generating the training data (source) and the test data (target) and several domain adaptation methods have been proposed to address this issue. While these approaches have considered the single source-single target scenario, it is plausible to have multiple sources and require adaptation to any possible target domain. This last scenario, named Domain Generalization (DG), is the focus of our work. Differently from previous DG methods which learn domain invariant representations from source data, we design a deep network with multiple domain-specific classifiers, each associated to a source domain. At test time we estimate the probabilities that a target sample belongs to each source domain and exploit them to optimally fuse the classifiers predictions. To further improve the generalization ability of our model, we also introduced a domain agnostic component supporting the final classifier. Experiments on two public benchmarks demonstrate the power of our approach
Contrastive Vicinal Space for Unsupervised Domain Adaptation
Recent unsupervised domain adaptation methods have utilized vicinal space
between the source and target domains. However, the equilibrium collapse of
labels, a problem where the source labels are dominant over the target labels
in the predictions of vicinal instances, has never been addressed. In this
paper, we propose an instance-wise minimax strategy that minimizes the entropy
of high uncertainty instances in the vicinal space to tackle the stated
problem. We divide the vicinal space into two subspaces through the solution of
the minimax problem: contrastive space and consensus space. In the contrastive
space, inter-domain discrepancy is mitigated by constraining instances to have
contrastive views and labels, and the consensus space reduces the confusion
between intra-domain categories. The effectiveness of our method is
demonstrated on public benchmarks, including Office-31, Office-Home, and
VisDA-C, achieving state-of-the-art performances. We further show that our
method outperforms the current state-of-the-art methods on PACS, which
indicates that our instance-wise approach works well for multi-source domain
adaptation as well. Code is available at https://github.com/NaJaeMin92/CoVi.Comment: 10 pages, 7 figures, 5 table
Kitting in the Wild through Online Domain Adaptation
Technological developments call for increasing perception and action capabilities of robots. Among other skills, vision systems that can adapt to any possible change in the working conditions are needed. Since these conditions are unpredictable, we need benchmarks which allow to assess the generalization and robustness capabilities of our visual recognition algorithms. In this work we focus on robotic kitting in unconstrained scenarios. As a first contribution, we present a new visual dataset for the kitting task. Differently from standard object recognition datasets, we provide images of the same objects acquired under various conditions where camera, illumination and background are changed. This novel dataset allows for testing the robustness of robot visual recognition algorithms to a series of different domain shifts both in isolation and unified. Our second contribution is a novel online adaptation algorithm for deep models, based on batch-normalization layers, which allows to continuously adapt a model to the current working conditions. Differently from standard domain adaptation algorithms, it does not require any image from the target domain at training time. We benchmark the performance of the algorithm on the proposed dataset, showing its capability to fill the gap between the performances of a standard architecture and its counterpart adapted offline to the given target domain
ROAD: Reality Oriented Adaptation for Semantic Segmentation of Urban Scenes
Exploiting synthetic data to learn deep models has attracted increasing
attention in recent years. However, the intrinsic domain difference between
synthetic and real images usually causes a significant performance drop when
applying the learned model to real world scenarios. This is mainly due to two
reasons: 1) the model overfits to synthetic images, making the convolutional
filters incompetent to extract informative representation for real images; 2)
there is a distribution difference between synthetic and real data, which is
also known as the domain adaptation problem. To this end, we propose a new
reality oriented adaptation approach for urban scene semantic segmentation by
learning from synthetic data. First, we propose a target guided distillation
approach to learn the real image style, which is achieved by training the
segmentation model to imitate a pretrained real style model using real images.
Second, we further take advantage of the intrinsic spatial structure presented
in urban scene images, and propose a spatial-aware adaptation scheme to
effectively align the distribution of two domains. These two modules can be
readily integrated with existing state-of-the-art semantic segmentation
networks to improve their generalizability when adapting from synthetic to real
urban scenes. We evaluate the proposed method on Cityscapes dataset by adapting
from GTAV and SYNTHIA datasets, where the results demonstrate the effectiveness
of our method.Comment: Add experiments on SYNTHIA, CVPR 2018 camera-ready versio
Causally Regularized Learning with Agnostic Data Selection Bias
Most of previous machine learning algorithms are proposed based on the i.i.d.
hypothesis. However, this ideal assumption is often violated in real
applications, where selection bias may arise between training and testing
process. Moreover, in many scenarios, the testing data is not even available
during the training process, which makes the traditional methods like transfer
learning infeasible due to their need on prior of test distribution. Therefore,
how to address the agnostic selection bias for robust model learning is of
paramount importance for both academic research and real applications. In this
paper, under the assumption that causal relationships among variables are
robust across domains, we incorporate causal technique into predictive modeling
and propose a novel Causally Regularized Logistic Regression (CRLR) algorithm
by jointly optimize global confounder balancing and weighted logistic
regression. Global confounder balancing helps to identify causal features,
whose causal effect on outcome are stable across domains, then performing
logistic regression on those causal features constructs a robust predictive
model against the agnostic bias. To validate the effectiveness of our CRLR
algorithm, we conduct comprehensive experiments on both synthetic and real
world datasets. Experimental results clearly demonstrate that our CRLR
algorithm outperforms the state-of-the-art methods, and the interpretability of
our method can be fully depicted by the feature visualization.Comment: Oral paper of 2018 ACM Multimedia Conference (MM'18
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