Polyphonic pitch detection by matching spectral and autocorrelation peaks

This paper describes a polyphonic multi-pitch detector which selects peaks as pitch candidates in both the spectrum and a multi-channel generalised autocorrelation. A final pitch is detected if a peak in the spectrum has a corresponding peak within the same semitone range in at least one of the autocorrelation channels. The autocorrelation is calculated in octave bands and all pre-processing steps like filtering, whitening and non-linear distortion are applied exclusively in the frequency domain for maximum flexibility in the parametrisation and high computational efficiency. An evaluation with common data sets yields good detection accuracies comparable to state of the art algorithms.