300 research outputs found
Non-convex regularization in remote sensing
In this paper, we study the effect of different regularizers and their
implications in high dimensional image classification and sparse linear
unmixing. Although kernelization or sparse methods are globally accepted
solutions for processing data in high dimensions, we present here a study on
the impact of the form of regularization used and its parametrization. We
consider regularization via traditional squared (2) and sparsity-promoting (1)
norms, as well as more unconventional nonconvex regularizers (p and Log Sum
Penalty). We compare their properties and advantages on several classification
and linear unmixing tasks and provide advices on the choice of the best
regularizer for the problem at hand. Finally, we also provide a fully
functional toolbox for the community.Comment: 11 pages, 11 figure
Confident Kernel Sparse Coding and Dictionary Learning
In recent years, kernel-based sparse coding (K-SRC) has received particular
attention due to its efficient representation of nonlinear data structures in
the feature space. Nevertheless, the existing K-SRC methods suffer from the
lack of consistency between their training and test optimization frameworks. In
this work, we propose a novel confident K-SRC and dictionary learning algorithm
(CKSC) which focuses on the discriminative reconstruction of the data based on
its representation in the kernel space. CKSC focuses on reconstructing each
data sample via weighted contributions which are confident in its corresponding
class of data. We employ novel discriminative terms to apply this scheme to
both training and test frameworks in our algorithm. This specific design
increases the consistency of these optimization frameworks and improves the
discriminative performance in the recall phase. In addition, CKSC directly
employs the supervised information in its dictionary learning framework to
enhance the discriminative structure of the dictionary. For empirical
evaluations, we implement our CKSC algorithm on multivariate time-series
benchmarks such as DynTex++ and UTKinect. Our claims regarding the superior
performance of the proposed algorithm are justified throughout comparing its
classification results to the state-of-the-art K-SRC algorithms.Comment: 10 pages, ICDM 2018 conferenc
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