Robust Phase Difference Estimation of Transients in High Noise Levels

This paper presents the Reassignment Vector Phase Difference Estimator (RVPDE), which gives noise robust relative phase estimates of oscillating transient signals in high noise levels. Estimation of relative phase information between signals is of interest for direction of arrival estimation, source separation and spatio-temporal decoding in neurology as well as for soundscape analysis. The RVPDE relies on the spectrogram reassignment vectors which contains information of the time-frequency local phase difference between two transient signals. The final estimate, which is robust to high noise levels, is given as the median over the local time-frequency area. The proposed technique is shown to outperform state-of-the-art methods in simulations for high noise levels. A discussion on the statistical distribution of the estimates is also presented, and finally an example of phase difference estimation of visually evoked potentials measured from electrical brain signals is shown.