162 research outputs found
Matchability of heterogeneous networks pairs
We consider the problem of graph matchability in non-identically distributed networks. In a general class of edge-independent networks, we demonstrate that graph matchability is almost surely lost when matching the networks directly, and is almost perfectly recovered when first centering the networks using Universal Singular Value Thresholding before matching. These theoretical results are then demonstrated in both real and synthetic simulation settings. We also recover analogous core-matchability results in a very general core-junk network model, wherein some vertices do not correspond between the graph pair.First author draf
Maximum Likelihood Estimation and Graph Matching in Errorfully Observed Networks
Given a pair of graphs with the same number of vertices, the inexact graph
matching problem consists in finding a correspondence between the vertices of
these graphs that minimizes the total number of induced edge disagreements. We
study this problem from a statistical framework in which one of the graphs is
an errorfully observed copy of the other. We introduce a corrupting channel
model, and show that in this model framework, the solution to the graph
matching problem is a maximum likelihood estimator. Necessary and sufficient
conditions for consistency of this MLE are presented, as well as a relaxed
notion of consistency in which a negligible fraction of the vertices need not
be matched correctly. The results are used to study matchability in several
families of random graphs, including edge independent models, random regular
graphs and small-world networks. We also use these results to introduce
measures of matching feasibility, and experimentally validate the results on
simulated and real-world networks
Ship Detection and Segmentation using Image Correlation
There have been intensive research interests in ship detection and
segmentation due to high demands on a wide range of civil applications in the
last two decades. However, existing approaches, which are mainly based on
statistical properties of images, fail to detect smaller ships and boats.
Specifically, known techniques are not robust enough in view of inevitable
small geometric and photometric changes in images consisting of ships. In this
paper a novel approach for ship detection is proposed based on correlation of
maritime images. The idea comes from the observation that a fine pattern of the
sea surface changes considerably from time to time whereas the ship appearance
basically keeps unchanged. We want to examine whether the images have a common
unaltered part, a ship in this case. To this end, we developed a method -
Focused Correlation (FC) to achieve robustness to geometric distortions of the
image content. Various experiments have been conducted to evaluate the
effectiveness of the proposed approach.Comment: 8 pages, to be published in proc. of conference IEEE SMC 201
Learning Feature Matching via Matchable Keypoint-Assisted Graph Neural Network
Accurately matching local features between a pair of images is a challenging
computer vision task. Previous studies typically use attention based graph
neural networks (GNNs) with fully-connected graphs over keypoints within/across
images for visual and geometric information reasoning. However, in the context
of feature matching, considerable keypoints are non-repeatable due to occlusion
and failure of the detector, and thus irrelevant for message passing. The
connectivity with non-repeatable keypoints not only introduces redundancy,
resulting in limited efficiency, but also interferes with the representation
aggregation process, leading to limited accuracy. Targeting towards high
accuracy and efficiency, we propose MaKeGNN, a sparse attention-based GNN
architecture which bypasses non-repeatable keypoints and leverages matchable
ones to guide compact and meaningful message passing. More specifically, our
Bilateral Context-Aware Sampling Module first dynamically samples two small
sets of well-distributed keypoints with high matchability scores from the image
pair. Then, our Matchable Keypoint-Assisted Context Aggregation Module regards
sampled informative keypoints as message bottlenecks and thus constrains each
keypoint only to retrieve favorable contextual information from intra- and
inter- matchable keypoints, evading the interference of irrelevant and
redundant connectivity with non-repeatable ones. Furthermore, considering the
potential noise in initial keypoints and sampled matchable ones, the MKACA
module adopts a matchability-guided attentional aggregation operation for purer
data-dependent context propagation. By these means, we achieve the
state-of-the-art performance on relative camera estimation, fundamental matrix
estimation, and visual localization, while significantly reducing computational
and memory complexity compared to typical attentional GNNs
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