Polar Coordinate Based Nonlinear Function for Frequency-Domain Blind Source Separation

Hiroshi SAWADA  Ryo MUKAI  Shoko ARAKI  Shoji MAKINO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E86-A   No.3   pp.590-596
Publication Date: 2003/03/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Blind Signal Processing: Independent Component Analysis and Signal Separation)
Category: Convolutive Systems
independent component analysis,  frequency domain,  complex-valued signal,  polar coordinate,  Cartesian coordinate,  

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This paper discusses a nonlinear function for independent component analysis to process complex-valued signals in frequency-domain blind source separation. Conventionally, nonlinear functions based on the Cartesian coordinates are widely used. However, such functions have a convergence problem. In this paper, we propose a more appropriate nonlinear function that is based on the polar coordinates of a complex number. In addition, we show that the difference between the two types of functions arises from the assumed densities of independent components. Our discussion is supported by several experimental results for separating speech signals, which show that the polar type nonlinear functions behave better than the Cartesian type.