Speed and accuracy enhancement of linear ICA techniques using rational nonlinear functions

  • Authors:
  • Petr Tichavský;Zbyněk Koldovsky;Erkki Oja

  • Affiliations:
  • Institute of Information Theory and Automation, Praha 8, Czech Republic;Institute of Information Theory and Automation, Praha 8, Czech Republic and Faculty of Mechatronic and Interdisciplinary Studies, Technical University of Liberec, Liberec, Czech Republic;Adaptive Informatics Research Centre, Helsinki University of Technology, HUT, Finland

  • Venue:
  • ICA'07 Proceedings of the 7th international conference on Independent component analysis and signal separation
  • Year:
  • 2007

Quantified Score

Hi-index 0.00

Visualization

Abstract

Many linear ICA techniques are based on minimizing a non-linear contrast function and many of them use a hyperbolic tangent (tanh) as their built-in nonlinearity. In this paper we propose two rational functions to replace the tanh and other popular functions that are tailored for separating supergaussian (long-tailed) sources. The advantage of the rational function is two-fold. First, the rational function requires a significantly lower computational complexity than tanh, e.g. nine times lower. As a result, algorithms using the rational functions are typically twice faster than algorithms with tanh. Second, it can be shown that a suitable selection of the rational function allows to achieve a better performance of the separation in certain scenarios. This improvement might be systematic, if the rational nonlinearities are selected adaptively to data.