2,512 research outputs found
Convolutional Neural Networks Via Node-Varying Graph Filters
Convolutional neural networks (CNNs) are being applied to an increasing
number of problems and fields due to their superior performance in
classification and regression tasks. Since two of the key operations that CNNs
implement are convolution and pooling, this type of networks is implicitly
designed to act on data described by regular structures such as images.
Motivated by the recent interest in processing signals defined in irregular
domains, we advocate a CNN architecture that operates on signals supported on
graphs. The proposed design replaces the classical convolution not with a
node-invariant graph filter (GF), which is the natural generalization of
convolution to graph domains, but with a node-varying GF. This filter extracts
different local features without increasing the output dimension of each layer
and, as a result, bypasses the need for a pooling stage while involving only
local operations. A second contribution is to replace the node-varying GF with
a hybrid node-varying GF, which is a new type of GF introduced in this paper.
While the alternative architecture can still be run locally without requiring a
pooling stage, the number of trainable parameters is smaller and can be
rendered independent of the data dimension. Tests are run on a synthetic source
localization problem and on the 20NEWS dataset.Comment: Submitted to DSW 2018 (IEEE Data Science Workshop
Indoor Semantic Segmentation using depth information
This work addresses multi-class segmentation of indoor scenes with RGB-D
inputs. While this area of research has gained much attention recently, most
works still rely on hand-crafted features. In contrast, we apply a multiscale
convolutional network to learn features directly from the images and the depth
information. We obtain state-of-the-art on the NYU-v2 depth dataset with an
accuracy of 64.5%. We illustrate the labeling of indoor scenes in videos
sequences that could be processed in real-time using appropriate hardware such
as an FPGA.Comment: 8 pages, 3 figure
Visual Saliency Based on Multiscale Deep Features
Visual saliency is a fundamental problem in both cognitive and computational
sciences, including computer vision. In this CVPR 2015 paper, we discover that
a high-quality visual saliency model can be trained with multiscale features
extracted using a popular deep learning architecture, convolutional neural
networks (CNNs), which have had many successes in visual recognition tasks. For
learning such saliency models, we introduce a neural network architecture,
which has fully connected layers on top of CNNs responsible for extracting
features at three different scales. We then propose a refinement method to
enhance the spatial coherence of our saliency results. Finally, aggregating
multiple saliency maps computed for different levels of image segmentation can
further boost the performance, yielding saliency maps better than those
generated from a single segmentation. To promote further research and
evaluation of visual saliency models, we also construct a new large database of
4447 challenging images and their pixelwise saliency annotation. Experimental
results demonstrate that our proposed method is capable of achieving
state-of-the-art performance on all public benchmarks, improving the F-Measure
by 5.0% and 13.2% respectively on the MSRA-B dataset and our new dataset
(HKU-IS), and lowering the mean absolute error by 5.7% and 35.1% respectively
on these two datasets.Comment: To appear in CVPR 201
Hierarchical Graph Convolutional Network Built by Multiscale Atlases for Brain Disorder Diagnosis Using Functional Connectivity
Functional connectivity network (FCN) data from functional magnetic resonance
imaging (fMRI) is increasingly used for the diagnoses of brain disorders.
However, state-of-the-art studies used to build the FCN using a single brain
parcellation atlas at a certain spatial scale, which largely neglected
functional interactions across different spatial scales in hierarchical
manners. In this study, we propose a novel framework to perform multiscale FCN
analysis for brain disorder diagnosis. We first use a set of well-defined
multiscale atlases to compute multiscale FCNs. Then, we utilize biologically
meaningful brain hierarchical relationships among the regions in multiscale
atlases to perform nodal pooling across multiple spatial scales, namely
"Atlas-guided Pooling". Accordingly, we propose a Multiscale-Atlases-based
Hierarchical Graph Convolutional Network (MAHGCN), built on the stacked layers
of graph convolution and the atlas-guided pooling, for a comprehensive
extraction of diagnostic information from multiscale FCNs. Experiments on
neuroimaging data from 1792 subjects demonstrate the effectiveness of our
proposed method in the diagnoses of Alzheimer's disease (AD), the prodromal
stage of AD (i.e., mild cognitive impairment [MCI]), as well as autism spectrum
disorder (ASD), with accuracy of 88.9%, 78.6%, and 72.7% respectively. All
results show significant advantages of our proposed method over other competing
methods. This study not only demonstrates the feasibility of brain disorder
diagnosis using resting-state fMRI empowered by deep learning, but also
highlights that the functional interactions in the multiscale brain hierarchy
are worth being explored and integrated into deep learning network
architectures for better understanding the neuropathology of brain disorders
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