Automatic chord recognition was one the key areas of research I focused on during my PhD at Queen Mary University of London. The aim of automatic chord recognition is to detect the currently played chord directly from audio analysis.
The algorithm I developed (jointly with Mark Plumbley) is now available as an open source C++ library under a GPL license.
2009 – Real-Time Chord Recognition For Live Performance
A. M. Stark and M. D. Plumbley. In Proceedings of the 2009 International Computer Music Conference (ICMC 2009), Montreal, Canada, 16-21 August 2009.