Multi-Pitch Estimation of Inharmonic Signals

Abstract: A signal with harmonic structure is often characterized by its fundamental frequency, or pitch. This single parameter contain vital information of a range of applications such as musical transcription, tuning of stringed instruments, speech processing and more. Some signal sources, for instance a sti vibrating string, exhibit waveforms with slightly deviating harmonic structure. This phenomenon is known as inharmonicity and it complicates the matter of estimating the fundamental frequency. If several signals with this inharmonic structure are added together, for instance for a musical chord from a stringed instrument, we arrive at the problem formulation of this work. How does one estimate the fundamental frequency of a multi-pitch signal containing inharmonicities? In this work we present a multi-pitch estimator able to handle inharmonic signals. This algorithm uses a source separating technique in order to apply a single pitch estimator to the resulting sub-problems. The performance of the estimator is evaluated and compared to other multi-pitch estimators with good results.