交替寻优生成元素幅值结合混沌随机相位构造循环测量矩阵?
Constructing circulant measurement matrix through alternating optimizing amplitudes together with chaotic sto chastic phases of the matrix generating elements
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摘要: 循环矩阵由于其对应离散卷积且具有快速算法被广泛应用于压缩测量矩阵。本文从循环测量矩阵生成元素的幅值和相位两个方面探索循环测量矩阵的优化构造,提出交替寻优生成元素的幅值并结合混沌随机相位实现循环测量矩阵的最优构造。由一维和二维信号循环测量矩阵的不同表示形式出发,将等价字典列向量之间互相干系数的Welch界作为逼近目标,推导出了一维和二维信号循环测量矩阵生成元素幅值优化的统一数学模型,提出采用交替寻优方法求解生成元素幅值的最优解。利用混沌序列构造循环测量矩阵生成元素的随机相位。与已有的典型循环测量矩阵相比,本文优化构造的循环测量矩阵所对应的等价字典列向量之间具有更低的互相干性,这正是所构造的循环测量矩阵优越性的本质所在。Abstract: Circulant measurement matrix has been widely used in compressive sensing because of its high-speed discrete convolution algorithm. The typical work of optimizing circulant measurement matrix was introduced by Wotao Yin in Reference [16]. Motivated by his work, the construction of circulant measurement matrix in this paper is explored from the view point of generating elements’ amplitudes and phases;and the optimal construction procedures are proposed based on alternately optimizing amplitudes in conjunction with chaotic stochastic phases of the matrix generating elements. The main idea of this paper is based on two innovations: The first one is to reduce the mutual coherence between column vectors of equivalent dictionary by alternately optimizing the generating elements’ amplitudes, thus improving the recovery performance of the circulant measurement matrix. From the different expressions of the circulant matrixes of one-dimensional and two-dimensional signal, by setting the Welch bound for the coe?cient of mutual coherence between the column vectors of equivalent dictionary as the approximation objective, two novel unified mathematical models are derived from the optimizing function for generating elements’ amplitudes of the two different matrixes. Optimal solutions for generating elements’ amplitudes are gained by alternately optimizing method. The second innovation is to construct the generating elements’ phases of circulant measurement matrix by utilization of a chaotic sequence with independent property. The chaotic stochastic phase of the circulant measurement matrix generating elements are generated by taking advantage of the chaotic internal certainty, which means an independent identically-distributed randomness sequence can be produced by the chaotic map with the initial value at certain sampling distance. At the same time, the external randomness of chaotic sequence can satisfy the stochastic requirement of circulant measurement matrix. This paper presents the method of constructing chaotic stochastic phase using Cat chaotic map. Experimental results of one-dimensional and two-dimensional signals in the optimized circulant measurement matrix are studied in this paper, which has a better performance as compared with the results of conventional circulant measurement matrixes, such as Gaussian circulant matrix and optimized circulant matrix proposed by Wotao Yin. The column vectors of equivalent dictionary in the optimized circulant measurement matrix have lower mutual coherence, this is the essence of the superiority of the optimized circulant matrix.
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