SeparateLead: Lead instrument (or main melody) Separation
By J. L. Durrieu

On the referenced webpage below, you can access sound examples, source code and Vamp plugin of algorithms described in the paper “A musically motivated mid-level representation for pitch estimation and musical audio source separation”, J.-L. Durrieu, B. David and G. Richard, IEEE Journal on Selected Topics on Signal Processing, special issue on Music Signal Processing, October 2011.

Links : to source code, sound examples, Vamp plugin