The Group Lasso for Stable Recovery of Block-Sparse Signal Representations

2011 ◽  
Vol 59 (4) ◽  
pp. 1371-1382 ◽  
Author(s):  
Xiaolei Lv ◽  
Guoan Bi ◽  
Chunru Wan
2013 ◽  
Vol 347-350 ◽  
pp. 3797-3803 ◽  
Author(s):  
Xiao Ning Song ◽  
Zi Liu

Sparse representations using overcomplete dictionaries has concentrated mainly on the study of pursuit algorithms that decompose signals with respect to a given dictionary. Designing dictionaries to better fit the above model can be done by either selecting one from a prespecified set of linear transforms or adapting the dictionary to a set of training signals. The K-SVD algorithm is an iterative method that alternates between sparse coding of the examples based on the current dictionary and a process of updating the dictionary atoms to better fit the data. However, the existing K-SVD algorithm is employed to dwell on the concept of a binary class assignment meaning that the multi-classes samples are assigned to the given classes definitely. The work proposed in this paper provides a novel fuzzy adaptive way to adapting dictionaries in order to achieve the fuzzy sparse signal representations, the update of the dictionary columns is combined with an update of the sparse representations by incorporated a new mechanism of fuzzy set, which is called fuzzy K-SVD. Experimental results conducted on the ORL and Yale face databases demonstrate the effectiveness of the proposed method.


2020 ◽  
Author(s):  
Yijun Zhong ◽  
Chongjun Li

Abstract Sparse signal representations have gained extensive study in recent years. In applications, there are large amounts of signals that are structured. Motivated by signal decomposition and scattered data reconstruction applications, we consider a particular type of structured signals which can be represented by a union of several sparse vectors. We define this type of signal as piecewise sparse signals. To find a piecewise sparse representation of a signal, we propose a thresholding version of piecewise orthogonal matching pursuit(TP OMP), which aims to overcome the disadvantages of P_OMP. We also establish the connection of piecewise sparsity and sampling over a union of subspaces. We evaluate the performance of the proposed greedy programs through simulations on surface reconstruction.


2020 ◽  
Vol 37 (5) ◽  
pp. 723-732
Author(s):  
Shengjie Zhao ◽  
Jianchen Zhu ◽  
Di Wu

Compressive sensing (CS) is a novel paradigm to recover a sparse signal in compressed domain. In some overcomplete dictionaries, most practical signals are sparse rather than orthonormal. Signal space greedy method can derive the optimal or near-optimal projections, making it possible to identify a few most relevant dictionary atoms of an arbitrary signal. More practically, such projections can be processed by standard CS recovery algorithms. This paper proposes a signal space subspace pursuit (SSSP) method to compute spare signal representations with overcomplete dictionaries, whenever the sensing matrix satisfies the restricted isometry property adapted to dictionary (D-RIP). Specifically, theoretical guarantees were provided to recover the signals from their measurements with overwhelming probability, as long as the sensing matrix satisfies the D-RIP. In addition, a thorough analysis was performed to minimize the number of measurements required for such guarantees. Simulation results demonstrate the validity of our hypothetical theory, as well as the superiority of the proposed approach.


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