48 research outputs found
スペクトルの線形性を考慮したハイパースペクトラル画像のノイズ除去とアンミキシングに関する研究
This study aims to generalize color line to M-dimensional spectral line feature (M>3) and introduce methods for denoising and unmixing of hyperspectral images based on the spectral linearity.For denoising, we propose a local spectral component decomposition method based on the spectral line. We first calculate the spectral line of an M-channel image, then using the line, we decompose the image into three components: a single M-channel image and two gray-scale images. By virtue of the decomposition, the noise is concentrated on the two images, thus the algorithm needs to denoise only two grayscale images, regardless of the number of channels. For unmixing, we propose an algorithm that exploits the low-rank local abundance by applying the unclear norm to the abundance matrix for local regions of spatial and abundance domains. In optimization problem, the local abundance regularizer is collaborated with the L2, 1 norm and the total variation.北九州市立大
Approximate Sparse Regularized Hyperspectral Unmixing
Sparse regression based unmixing has been recently proposed to estimate the abundance of materials present in hyperspectral image pixel. In this paper, a novel sparse unmixing optimization model based on approximate sparsity, namely, approximate sparse unmixing (ASU), is firstly proposed to perform the unmixing task for hyperspectral remote sensing imagery. And then, a variable splitting and augmented Lagrangian algorithm is introduced to tackle the optimization problem. In ASU, approximate sparsity is used as a regularizer for sparse unmixing, which is sparser than l1 regularizer and much easier to be solved than l0 regularizer. Three simulated and one real hyperspectral images were used to evaluate the performance of the proposed algorithm in comparison to l1 regularizer. Experimental results demonstrate that the proposed algorithm is more effective and accurate for hyperspectral unmixing than state-of-the-art l1 regularizer
Variable-Wise Diagonal Preconditioning for Primal-Dual Splitting: Design and Applications
This paper proposes a method of designing appropriate diagonal
preconditioners for a preconditioned primal-dual splitting method (P-PDS).
P-PDS can efficiently solve various types of convex optimization problems
arising in signal processing and image processing. Since the appropriate
diagonal preconditioners that accelerate the convergence of P-PDS vary greatly
depending on the structure of the target optimization problem, a design method
of diagonal preconditioners for PPDS has been proposed to determine them
automatically from the problem structure. However, the existing method has two
limitations: it requires direct access to all elements of the matrices
representing the linear operators involved in the target optimization problem,
and it is element-wise preconditioning, which makes certain types of proximity
operators impossible to compute analytically. To overcome these limitations, we
establish an Operator-norm-based design method of Variable-wise Diagonal
Preconditioning (OVDP). First, the diagonal preconditioners constructed by OVDP
are defined using only the operator norm or its upper bound of the linear
operator thus eliminating the need for their explicit matrix representations.
Furthermore, since our method is variable-wise preconditioning, it keeps all
proximity operators efficiently computable. We also prove that our
preconditioners satisfy the convergence conditions of PPDS. Finally, we
demonstrate the effectiveness and utility of our method through applications to
hyperspectral image mixed noise removal, hyperspectral unmixing, and graph
signal recovery.Comment: Submitted to IEEE Transactions on Signal Processin
Image Processing and Machine Learning for Hyperspectral Unmixing: An Overview and the HySUPP Python Package
Spectral pixels are often a mixture of the pure spectra of the materials,
called endmembers, due to the low spatial resolution of hyperspectral sensors,
double scattering, and intimate mixtures of materials in the scenes. Unmixing
estimates the fractional abundances of the endmembers within the pixel.
Depending on the prior knowledge of endmembers, linear unmixing can be divided
into three main groups: supervised, semi-supervised, and unsupervised (blind)
linear unmixing. Advances in Image processing and machine learning
substantially affected unmixing. This paper provides an overview of advanced
and conventional unmixing approaches. Additionally, we draw a critical
comparison between advanced and conventional techniques from the three
categories. We compare the performance of the unmixing techniques on three
simulated and two real datasets. The experimental results reveal the advantages
of different unmixing categories for different unmixing scenarios. Moreover, we
provide an open-source Python-based package available at
https://github.com/BehnoodRasti/HySUPP to reproduce the results
Robust Constrained Hyperspectral Unmixing Using Reconstructed-Image Regularization
Hyperspectral (HS) unmixing is the process of decomposing an HS image into
material-specific spectra (endmembers) and their spatial distributions
(abundance maps). Existing unmixing methods have two limitations with respect
to noise robustness. First, if the input HS image is highly noisy, even if the
balance between sparse and piecewise-smooth regularizations for abundance maps
is carefully adjusted, noise may remain in the estimated abundance maps or
undesirable artifacts may appear. Second, existing methods do not explicitly
account for the effects of stripe noise, which is common in HS measurements, in
their formulations, resulting in significant degradation of unmixing
performance when such noise is present in the input HS image. To overcome these
limitations, we propose a new robust hyperspectral unmixing method based on
constrained convex optimization. Our method employs, in addition to the two
regularizations for the abundance maps, regularizations for the HS image
reconstructed by mixing the estimated abundance maps and endmembers. This
strategy makes the unmixing process much more robust in highly-noisy scenarios,
under the assumption that the abundance maps used to reconstruct the HS image
with desirable spatio-spectral structure are also expected to have desirable
properties. Furthermore, our method is designed to accommodate a wider variety
of noise including stripe noise. To solve the formulated optimization problem,
we develop an efficient algorithm based on a preconditioned primal-dual
splitting method, which can automatically determine appropriate stepsizes based
on the problem structure. Experiments on synthetic and real HS images
demonstrate the advantages of our method over existing methods.Comment: Submitted to IEEE Transactions on Geoscience and Remote Sensin
A convex model for non-negative matrix factorization and dimensionality reduction on physical space
A collaborative convex framework for factoring a data matrix into a
non-negative product , with a sparse coefficient matrix , is proposed.
We restrict the columns of the dictionary matrix to coincide with certain
columns of the data matrix , thereby guaranteeing a physically meaningful
dictionary and dimensionality reduction. We use regularization
to select the dictionary from the data and show this leads to an exact convex
relaxation of in the case of distinct noise free data. We also show how
to relax the restriction-to- constraint by initializing an alternating
minimization approach with the solution of the convex model, obtaining a
dictionary close to but not necessarily in . We focus on applications of the
proposed framework to hyperspectral endmember and abundances identification and
also show an application to blind source separation of NMR data.Comment: 14 pages, 9 figures. EE and JX were supported by NSF grants
{DMS-0911277}, {PRISM-0948247}, MM by the German Academic Exchange Service
(DAAD), SO and MM by NSF grants {DMS-0835863}, {DMS-0914561}, {DMS-0914856}
and ONR grant {N00014-08-1119}, and GS was supported by NSF, NGA, ONR, ARO,
DARPA, and {NSSEFF.
Image Restoration for Remote Sensing: Overview and Toolbox
Remote sensing provides valuable information about objects or areas from a
distance in either active (e.g., RADAR and LiDAR) or passive (e.g.,
multispectral and hyperspectral) modes. The quality of data acquired by
remotely sensed imaging sensors (both active and passive) is often degraded by
a variety of noise types and artifacts. Image restoration, which is a vibrant
field of research in the remote sensing community, is the task of recovering
the true unknown image from the degraded observed image. Each imaging sensor
induces unique noise types and artifacts into the observed image. This fact has
led to the expansion of restoration techniques in different paths according to
each sensor type. This review paper brings together the advances of image
restoration techniques with particular focuses on synthetic aperture radar and
hyperspectral images as the most active sub-fields of image restoration in the
remote sensing community. We, therefore, provide a comprehensive,
discipline-specific starting point for researchers at different levels (i.e.,
students, researchers, and senior researchers) willing to investigate the
vibrant topic of data restoration by supplying sufficient detail and
references. Additionally, this review paper accompanies a toolbox to provide a
platform to encourage interested students and researchers in the field to
further explore the restoration techniques and fast-forward the community. The
toolboxes are provided in https://github.com/ImageRestorationToolbox.Comment: This paper is under review in GRS