We are exploring automatic transcription of bell chiming recordins. Bell chiming is a Slovenian folk music tradition involving performers playing tunes on church bells by holding the clapper and striking the rim of a stationary bell. The tunes played consist of repeated rhythmic patterns into which various changes are included.
Our goal is to design robust automatic algorithms for transcription of bell chiming recordings that would enable search and retrieval of this part of Slovenian folk music heritage within the Ethnomuse digital archive.
We also develop algorithms for transcription of other bell music, such as bell clock melodies (see papers below).
Our algorithm for transcription of bell chiming recordings is based on non-negative matrix factorization. Because the sounds of bells are inharmonic and their tuning not known in advance, we perform transcription in two steps. First, by analyzing the covariance matrix of the time-frequency representation of a recording, we estimate the number of bells and their approximate spectra using prior knowledge of church bell acoustics and bell chiming performance rules. Transcription is then performed by applying a non-negative matrix factorization algorithm with selective sparsity constraints to learn the basis vectors that approximate the previously estimated bell spectra, while adapting the number of basis vectors during learning.
For more details, see:

@article{8992340,
author = {Marolt, Matija},
journal = {IEEE transactions on audio, speech, and language processing},
number = {3},
year = {2012},
pages = {844--853},
title = {Automatic transcription of bell chiming recordings},
volume = {20},
}

@article{9286996,
author = {Lefeber, Marieke and van Kranenburg, Peter and Marolt, Matija},
journal = {Tijdschrift van de Koninklijke Vereniging voor Nederlandse Muziekgeschiedenis},
number = {12},
year = {2011},
pages = {147--161},
title = {Identificatie van repertoire van achtiende-eeuwse bellen- speelklokken op basis van automatische vergelijking},
volume = {61},
}

@inproceedings{7224404,
author = {Marolt, Matija},
booktitle = {SMC 2009 : proceedings of the 6th {Sound} and {Music} {Computing} {Conference}, 23-25 {July} 2009 {Casa} da {M}{\' u}sica, {Porto} - {Portugal}},
year = {2009},
pages = {137--142},
title = {Non-negative matrix factorization with selective sparsity constraints for transcription of bell chiming recordings},
}