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Báo cáo hóa học: " Research Article Removing the Influence of Shimmer in the Calculation of Harmonics-To-Noise Ratios Using Ensemble-Averages in Voice Signals"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Removing the Influence of Shimmer in the Calculation of Harmonics-To-Noise Ratios Using Ensemble-Averages in Voice Signals | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 784379 7 pages doi 10.1155 2009 784379 Research Article Removing the Influence of Shimmer in the Calculation of Harmonics-To-Noise Ratios Using Ensemble-Averages in Voice Signals Carlos Ferrer Eduardo Gonzalez Maria E. Hernandez-Diaz Diana Torres and Anesto del Toro Center for Studies on Electronics and Information Technologies Central University of Las Villas C. Camajuani km 5.5 Santa Clara CP 54830 Cuba Correspondence should be addressed to Carlos Ferrer cferrer@uclv.edu.cu Received 1 November 2008 Revised 10 March 2009 Accepted 13 April 2009 Recommended by Juan I. Godino-Llorente Harmonics-to-noise ratios HNRs are affected by general aperiodicity in voiced speech signals. To specifically reflect a signal-to-additive-noise ratio the measurement should be insensitive to other periodicity perturbations like jitter shimmer and waveform variability. The ensemble averaging technique is a time-domain method which has been gradually refined in terms of its sensitivity to jitter and waveform variability and required number of pulses. In this paper shimmer is introduced in the model of the ensemble average and a formula is derived which allows the reduction of shimmer effects in HNR calculation. The validity of the technique is evaluated using synthetically shimmered signals and the prerequisites glottal pulse positions and amplitudes are obtained by means of fully automated methods. The results demonstrate the feasibility and usefulness of the correction. Copyright 2009 Carlos Ferrer et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. Introduction When the source-filter model of speech production 1 is assumed in Type 1 2 signals no apparent bifurca-tions chaos the sources of periodicity perturbations in