Auditory-inspired pitch extraction using a Synchrony Capture Filterbank and phase alignment

Abstract

The question of how harmonic sounds produce strong, low pitches at their fundamental frequencies, f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> s, has been of theoretical and practical interest to scientists and engineers for many decades. Currently the best auditory models for f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> pitch, e.g. [1], are based on bandpass filtering (cochlear mechanics), half-wave rectification and low-pass filtering (haircell transduction and synaptic transmission), channel autocorrelations (all-order interspike interval statistics) aggregated into a summary autocorrelation, and an analysis that determines the most prevalent interspike intervals. As a possible alternative to autocorrelation computations, we propose an alternative model that uses an adaptive Synchrony Capture Filterbank (SCFB) in which groups of filters or channels in a filterbank neighborhood are driven exclusively (captured) by dominant frequency components that are closest to them. The channel outputs are then adaptively phase aligned with respect to a common time reference to compute a Summary Phase Aligned Function (SPAF), aggregated across all channels, from which f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> can be easily extracted.