引入参考信号的新峭度快速不动点算法
Fast Fixed-point Algorithm for New Kurtosis by Introducing the Reference Signals
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摘要: 在盲源分离和独立成分分析中,峭度是衡量随机信号非高斯性的常用对比准则,通过不同类型的算法对其进行优化,找到非高斯性极大值点,即实现了源信号的提取或分离。例如,基于峭度的快速不动点算法,它是一种收敛速度很快的算法。最近,Marc Castella等人提出了一类基于所谓“参考信号”的对比准则,以及对应的梯度最大化优化算法,这些算法具有很好的收敛性能。受其启发,文章以一种类似的方式将“参考信号”思想应用到峭度中,得到一种新颖的对比函数,并基于该新峭度对比函数,提出了一种新的快速不动点算法。与经典的基于峭度的快速不动点算法相比,该算法极大地提高了收敛速度,尤其是随着信号样值点数的增加,该算法的优势会更加明显。文章分析和证明了该新峭度对比函数的局部收敛性,给出了新算法的详细推导过程,仿真实验验证了该算法的性能,并与经典算法进行了比较分析。Abstract: In the blind source separation (BSS) and independent component analysis (ICA),kurtosis is a common contrast measure for non-gaussianity of stochastic signals. The source signals can be extracted or recovered by using different optimization algorithms to find the non-gaussianity maximization points. For instance, the fast fixed-point algorithm based on kurtosis is a very classical one, which has very fast convergence speed. Recently,a family of so-called reference-based contrast criteria have been proposed by Marc Castella etc, and corresponding gradient maximization algorithms have also been proposed, which show very good performance. Inspired by them, the reference-based scheme is applied in kurtosis to construct a new kurtosis contrast function in a similar manner, based on which a novel fast fixed-point algorithm is proposed in this paper. Compared with the classical kurtosis-based fast fixed-point algorithm, this new algorithm is much more efficient in terms of computational speed, which is significantly apparent with large number of samples. The local consistency of this new contrast function is analyzed and proved, and the derivation of this new algorithm is also presented in detail. The performance of this new algorithm is validated through simulations, together with corresponding comparison and analysis.