15,651 research outputs found
An Efficient Approximate kNN Graph Method for Diffusion on Image Retrieval
The application of the diffusion in many computer vision and artificial
intelligence projects has been shown to give excellent improvements in
performance. One of the main bottlenecks of this technique is the quadratic
growth of the kNN graph size due to the high-quantity of new connections
between nodes in the graph, resulting in long computation times. Several
strategies have been proposed to address this, but none are effective and
efficient. Our novel technique, based on LSH projections, obtains the same
performance as the exact kNN graph after diffusion, but in less time
(approximately 18 times faster on a dataset of a hundred thousand images). The
proposed method was validated and compared with other state-of-the-art on
several public image datasets, including Oxford5k, Paris6k, and Oxford105k
Distributed Low-rank Subspace Segmentation
Vision problems ranging from image clustering to motion segmentation to
semi-supervised learning can naturally be framed as subspace segmentation
problems, in which one aims to recover multiple low-dimensional subspaces from
noisy and corrupted input data. Low-Rank Representation (LRR), a convex
formulation of the subspace segmentation problem, is provably and empirically
accurate on small problems but does not scale to the massive sizes of modern
vision datasets. Moreover, past work aimed at scaling up low-rank matrix
factorization is not applicable to LRR given its non-decomposable constraints.
In this work, we propose a novel divide-and-conquer algorithm for large-scale
subspace segmentation that can cope with LRR's non-decomposable constraints and
maintains LRR's strong recovery guarantees. This has immediate implications for
the scalability of subspace segmentation, which we demonstrate on a benchmark
face recognition dataset and in simulations. We then introduce novel
applications of LRR-based subspace segmentation to large-scale semi-supervised
learning for multimedia event detection, concept detection, and image tagging.
In each case, we obtain state-of-the-art results and order-of-magnitude speed
ups
DCVQE: A Hierarchical Transformer for Video Quality Assessment
The explosion of user-generated videos stimulates a great demand for
no-reference video quality assessment (NR-VQA). Inspired by our observation on
the actions of human annotation, we put forward a Divide and Conquer Video
Quality Estimator (DCVQE) for NR-VQA. Starting from extracting the frame-level
quality embeddings (QE), our proposal splits the whole sequence into a number
of clips and applies Transformers to learn the clip-level QE and update the
frame-level QE simultaneously; another Transformer is introduced to combine the
clip-level QE to generate the video-level QE. We call this hierarchical
combination of Transformers as a Divide and Conquer Transformer (DCTr) layer.
An accurate video quality feature extraction can be achieved by repeating the
process of this DCTr layer several times. Taking the order relationship among
the annotated data into account, we also propose a novel correlation loss term
for model training. Experiments on various datasets confirm the effectiveness
and robustness of our DCVQE model.Comment: Accepted by ACCV202
From Data Topology to a Modular Classifier
This article describes an approach to designing a distributed and modular
neural classifier. This approach introduces a new hierarchical clustering that
enables one to determine reliable regions in the representation space by
exploiting supervised information. A multilayer perceptron is then associated
with each of these detected clusters and charged with recognizing elements of
the associated cluster while rejecting all others. The obtained global
classifier is comprised of a set of cooperating neural networks and completed
by a K-nearest neighbor classifier charged with treating elements rejected by
all the neural networks. Experimental results for the handwritten digit
recognition problem and comparison with neural and statistical nonmodular
classifiers are given
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