312 research outputs found
Hyperspectral Image Restoration via Total Variation Regularized Low-rank Tensor Decomposition
Hyperspectral images (HSIs) are often corrupted by a mixture of several types
of noise during the acquisition process, e.g., Gaussian noise, impulse noise,
dead lines, stripes, and many others. Such complex noise could degrade the
quality of the acquired HSIs, limiting the precision of the subsequent
processing. In this paper, we present a novel tensor-based HSI restoration
approach by fully identifying the intrinsic structures of the clean HSI part
and the mixed noise part respectively. Specifically, for the clean HSI part, we
use tensor Tucker decomposition to describe the global correlation among all
bands, and an anisotropic spatial-spectral total variation (SSTV)
regularization to characterize the piecewise smooth structure in both spatial
and spectral domains. For the mixed noise part, we adopt the norm
regularization to detect the sparse noise, including stripes, impulse noise,
and dead pixels. Despite that TV regulariztion has the ability of removing
Gaussian noise, the Frobenius norm term is further used to model heavy Gaussian
noise for some real-world scenarios. Then, we develop an efficient algorithm
for solving the resulting optimization problem by using the augmented Lagrange
multiplier (ALM) method. Finally, extensive experiments on simulated and
real-world noise HSIs are carried out to demonstrate the superiority of the
proposed method over the existing state-of-the-art ones.Comment: 15 pages, 20 figure
Interpretable Hyperspectral AI: When Non-Convex Modeling meets Hyperspectral Remote Sensing
Hyperspectral imaging, also known as image spectrometry, is a landmark
technique in geoscience and remote sensing (RS). In the past decade, enormous
efforts have been made to process and analyze these hyperspectral (HS) products
mainly by means of seasoned experts. However, with the ever-growing volume of
data, the bulk of costs in manpower and material resources poses new challenges
on reducing the burden of manual labor and improving efficiency. For this
reason, it is, therefore, urgent to develop more intelligent and automatic
approaches for various HS RS applications. Machine learning (ML) tools with
convex optimization have successfully undertaken the tasks of numerous
artificial intelligence (AI)-related applications. However, their ability in
handling complex practical problems remains limited, particularly for HS data,
due to the effects of various spectral variabilities in the process of HS
imaging and the complexity and redundancy of higher dimensional HS signals.
Compared to the convex models, non-convex modeling, which is capable of
characterizing more complex real scenes and providing the model
interpretability technically and theoretically, has been proven to be a
feasible solution to reduce the gap between challenging HS vision tasks and
currently advanced intelligent data processing models
Revisiting Nonlocal Self-Similarity from Continuous Representation
Nonlocal self-similarity (NSS) is an important prior that has been
successfully applied in multi-dimensional data processing tasks, e.g., image
and video recovery. However, existing NSS-based methods are solely suitable for
meshgrid data such as images and videos, but are not suitable for emerging
off-meshgrid data, e.g., point cloud and climate data. In this work, we revisit
the NSS from the continuous representation perspective and propose a novel
Continuous Representation-based NonLocal method (termed as CRNL), which has two
innovative features as compared with classical nonlocal methods. First, based
on the continuous representation, our CRNL unifies the measure of
self-similarity for on-meshgrid and off-meshgrid data and thus is naturally
suitable for both of them. Second, the nonlocal continuous groups can be more
compactly and efficiently represented by the coupled low-rank function
factorization, which simultaneously exploits the similarity within each group
and across different groups, while classical nonlocal methods neglect the
similarity across groups. This elaborately designed coupled mechanism allows
our method to enjoy favorable performance over conventional NSS methods in
terms of both effectiveness and efficiency. Extensive multi-dimensional data
processing experiments on-meshgrid (e.g., image inpainting and image denoising)
and off-meshgrid (e.g., climate data prediction and point cloud recovery)
validate the versatility, effectiveness, and efficiency of our CRNL as compared
with state-of-the-art methods
Adaptive Regularized Low-Rank Tensor Decomposition for Hyperspectral Image Denoising and Destriping
Hyperspectral images (HSIs) are inevitably degraded by a mixture of various
types of noise, such as Gaussian noise, impulse noise, stripe noise, and dead
pixels, which greatly limits the subsequent applications. Although various
denoising methods have already been developed, accurately recovering the
spatial-spectral structure of HSIs remains a challenging problem to be
addressed. Furthermore, serious stripe noise, which is common in real HSIs, is
still not fully separated by the previous models. In this paper, we propose an
adaptive hyperLaplacian regularized low-rank tensor decomposition (LRTDAHL)
method for HSI denoising and destriping. On the one hand, the stripe noise is
separately modeled by the tensor decomposition, which can effectively encode
the spatial-spectral correlation of the stripe noise. On the other hand,
adaptive hyper-Laplacian spatial-spectral regularization is introduced to
represent the distribution structure of different HSI gradient data by
adaptively estimating the optimal hyper-Laplacian parameter, which can reduce
the spatial information loss and over-smoothing caused by the previous total
variation regularization. The proposed model is solved using the alternating
direction method of multipliers (ADMM) algorithm. Extensive simulation and
real-data experiments all demonstrate the effectiveness and superiority of the
proposed method
Multi-scale spatial fusion and regularization induced unsupervised auxiliary task CNN model for deep super-resolution of hyperspectral image.
Hyperspectral images (HSI) features rich spectral information in many narrow bands but at a cost of a relatively low spatial resolution. As such, various methods have been developed for enhancing the spatial resolution of the low-resolution HSI (Lr-HSI) by fusing it with high-resolution multispectral images (Hr-MSI). The difference in spectrum range and spatial dimensions between the Lr-HSI and Hr-SI have been fundamental but challenging for multispectral/hyperspectral (MS/HS) fusion. In this paper, a multi-scale spatial fusion and regularization induced auxiliary task (MSAT) based CNN model is proposed for deep super-resolution of HSI, where a Lr-HSI is fused with a Hr-MSI to reconstruct a high-resolution HSI (Hr-HSI) counterpart. The multi-scale fusion is used to efficiently address the discrepancy in spatial resolutions between two inputs. Based on the general assumption that the acquired Hr-MSI and the reconstructed Hr-HSI share similar underlying characteristics, the auxiliary task is proposed to learn a representation for improved generality of the model and reduced overfitting. Experimental results on three public datasets have validated the effectiveness of our approach in comparison with several state-of-the-art methods
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