Signal representation and estimation of spectral parameters by inharmonic comb filters with application to the piano

A method for signal representation in the frequency domain is described, using a comb filter design with nonequidistant spacing of the filter bands (inharmonic comb filter). This approach offers several advantages when studying the properties of a signal source with inharmonic components. An analytical relation between the partial frequencies, or some hypothesis of this relation, is needed beforehand. An application of the method is presented in which piano tones are visualized in a new way, allowing for an automatic and accurate measurement of fundamental frequency and inharmonicity coefficient. Possible directions for further development and some interesting application areas are discussed.