Subjective Melodic Similarity based on Extended Implication-Realization Model

Abstract

This paper proposes how to measure similarity of melodies based on Implication-Realization Model (IRM). IRM is a music theory based on abstracting music and then expressing music through symbol sequences which is information constituting the music such as pitch, rhythm, and rests and so on. This paper especially extends IRM so that the theory becomes much more appropriate to measuring similarity of melodies. More specifically, compared with the symbols of the original IRM, we introduce finer grained symbols by simply distinguishing up and down of interval directions and by dividing each most symbols of the original IRM into two extended symbols. Furthermore, we implement a parser that transforms note sequence of an input melody into a sequence of the extended IRM symbols. The results of experimental evaluation through subjective human judgments show that the proposed extended IRM symbols outperform the original IRM symbols with respect to measuring similarity of melodies.