ism: Improvisation Supporting System based on Melody Correction

In this paper, we describe a novel improvisation supporting system based on correcting musically unnatural melodies. Since improvisation is the musical performance style that involves creating melodies while playing, it is not easy even for the people who can play musical instruments. However, previous studies have not dealt with improvisation support for the people who can play musical instruments but cannot improvise. In this study, to support such players’ improvisation, we propose a novel improvisation supporting system called ism, which corrects musically unnatural melodies automatically. The main issue in realizing this system is how to detect notes to be corrected (i.e., musically unnatural or inappropriate). We propose a method for detecting notes to be corrected based on the N-gram model. This method first calculates N-gram probabilities of played notes, and then judges notes with low N-gram probabilities to be corrected. Experimental results show that the N-gram-based melody correction and the proposed system are useful for supporting improvisation.