For compressed sensing over arbitrarily connected networks, we consider the problem of estimating underlying sparse signals in a distributed manner. We introduce a new signal model that helps to describe inter-signal correlation among connected nodes. Based on this signal model along with a brief survey of existing greedy algorithms, we develop distributed greedy algorithms with low communication overhead. Incorporating appropriate modifications, we design two new distributed algorithms where the local algorithms are based on appropriately modified existing orthogonal matching pursuit and subspace pursuit. Further, by combining advantages of these two local algorithms, we design a new greedy algorithm that is well suited for a distributed scenario. By extensive simulations we demonstrate that the new algorithms in a sparsely connected network provide good performance, close to the performance of a centralized greedy solution.
We study here sparse recovery problems in the presence of additive noise. We analyze a thresholding version of the CoSaMP algorithm, named Thresholding Greedy Pursuit (TGP). We demonstrate that an appropriate choice of thresholding parameter, even without the knowledge of sparsity level of the signal and strength of the noise, can result in exact recovery with no false discoveries as the dimension of the data increases to infinity.
MAP Support Detection for Greedy Sparse Signal Recovery Algorithms in Compressive Sensing
Intel Labs(英特尔实验室);University of Texas at Austin(德克萨斯大学奥斯汀分校)
一个可靠的支持检测是必不可少的贪心算法从压缩和噪声测量准确地重建稀疏信号。提出了一种新的贪心算法支持度检测方法--\textit{maximum a posteriori (MAP) support detection}。不同于现有的支持检测方法,确定支持指数的幅度最大的相关值,每次迭代,所提出的方法选择他们的最大似然比计算下的真实和空的支持假设,同时利用传感矩阵,稀疏信号和噪声的分布。利用这种技术,MAP匹配追踪(MAP-MP)首次提出了利用建议的支持检测方法的优点,并推导出了一个充分条件时,稀疏信号是二进制的情况下,完美的信号恢复。随后,一组迭代的贪心算法,称为MAP-广义正交匹配追踪(MAP-gOMP),MAP-压缩采样匹配追踪(MAP-CoSaMP),和MAP-子空间追踪(MAP-SP),以证明所提出的支持检测方法现有的贪心算法的适用性。实验结果表明,所提出的贪心算法具有高可靠性的支持检测,可以更好,更快,更容易实现比通过线性规划的基追踪。
We propose a novel greedy algorithm for the support recovery of a sparse signal from a small number of noisy measurements. In the proposed method, a new support index is identified for each iteration based on bit-wise maximum a posteriori (B-MAP) detection. This is optimal in the sense of detecting one of the remaining support indices, provided that all the detected indices in the previous iterations are correct. Despite its optimality, it requires an expensive complexity for computing the maximization metric (i.e., a posteriori probability of each remaining support) due to the marginalization…
Exact Recovery of Sparse Signals via Orthogonal Matching Pursuit: How Many Iterations Do We Need?
正交匹配追踪(OMP)是一种广泛应用于从压缩测量中恢复稀疏信号的贪心算法。在本文中,我们分析了OMP算法进行精确恢复稀疏信号所需的迭代次数。我们的分析表明,OMP可以准确地恢复所有的$K$稀疏信号的$\lceil 2.8 K \rceil$迭代时,测量矩阵满足限制等距属性(RIP)。我们的结果改进了张的结果,也弥补了张的结果和OMP的基本极限之间的差距,在该极限下$K$ -稀疏信号的精确恢复不能得到一致的保证。
Motivated by the question of optimal functional approximation via compressed sensing, we propose generalizations of the Iterative Hard Thresholding and the Compressive Sampling Matching Pursuit algorithms able to promote sparse in levels signals. We show, by means of numerical experiments, that the proposed algorithms are successfully able to outperform their unstructured variants when the signal exhibits the sparsity structure of interest. Moreover, in the context of piecewise smooth function approximation, we numerically demonstrate that the structure promoting decoders outperform their unst…
Compressed Sensing (CS) is a signal processing technique which can accurately recover sparse signals from linear measurements with far fewer number of measurements than those required by the classical Shannon-Nyquist theorem. Block sparse signals, i.e., the sparse signals whose nonzero coefficients occur in few blocks, arise from many fields. Block orthogonal matching pursuit (BOMP) is a popular greedy algorithm for recovering block sparse signals due to its high efficiency and effectiveness. By fully using the block sparsity of block sparse signals, BOMP can achieve very good recovery perform…
Aston University(阿斯顿大学);Czech Academy of Sciences(捷克科学院);Indian Institute of Science, Bangalore(班加罗尔印度科学学院)
The convergence and numerical analysis of a low memory implementation of the Orthogonal Matching Pursuit greedy strategy, which is termed Self Projected Matching Pursuit, is presented. This approach renders an iterative way of solving the least squares problem with much less storage requirement than direct linear algebra techniques. Hence, it appropriate for solving large linear systems. The analysis highlights its suitability within the class of well posed problems.
Compressive Sensing (CS) is a new paradigm for the efficient acquisition of signals that have sparse representation in a certain domain. Traditionally, CS has provided numerous methods for signal recovery over an orthonormal basis. However, modern applications have sparked the emergence of related methods for signals not sparse in an orthonormal basis but in some arbitrary, perhaps highly overcomplete, dictionary, particularly due to their potential to generate different kinds of sparse representation of signals. To this end, we apply a signal space greedy method, which relies on the ability t…
Instituto de Sistemas e Robótica (ISR), Instituto Superior Técnico (IST), Technical University of Lisbon, Portugal(里斯本理工大学高等技术学院系统机器人研究所);Department of Electrical and Computer Engineering at Carnegie Mellon University, USA(卡内基梅隆大学电气与计算机工程系);Department of Computer Science at ETH Zurich, Switzerland(苏黎世联邦理工学院计算机科学系)
Finding the best K-sparse approximation of a signal in a redundant dictionary is an NP-hard problem. Suboptimal greedy matching pursuit (MP) algorithms are generally used for this task. In this work, we present an acceleration technique and an implementation of the matching pursuit algorithm acting on a multi-Gabor dictionary, i.e., a concatenation of several Gabor-type time-frequency dictionaries, each of which consisting of translations and modulations of a possibly different window and time and frequency shift parameters. The technique is based on pre-computing and thresholding inner produc…
We consider the estimation distortion of a distributed sensing system with finite number of sensor nodes, in which the nodes observe a common phenomenon and transmit their observations to a fusion center over orthogonal channels. In particular, we investigate whether the coded scheme (separate source-channel coding) outperforms the uncoded scheme (joint source-channel coding) or not. To this end, we explicitly derive the estimation distortion of a coded heterogeneous sensing system with diverse node and channel configurations. Based on this result, we show that in a homogeneous sensing system …