A Hardware-Oriented Algorithm for Real-Time Music Key Signature Recognition

Abstract

The algorithm presented in this paper provides the means for the real-time recognition of the key signature associated with a given piece of music, based on the analysis of a very small number of initial notes. The algorithm can easily be implemented in electronic musical instruments, enabling real-time generation of musical notation. The essence of the solution proposed herein boils down to the analysis of a music signature, defined as a set of twelve vectors representing the particular pitch classes. These vectors are anchored in the center of the circle of fifths, pointing radially towards each of the twelve tones of the chromatic scale. Besides a thorough description of the algorithm, the authors also present a theoretical introduction to the subject matter. The results of the experiments performed on preludes and fugues by J.S. Bach, as well as the preludes, nocturnes, and etudes of F. Chopin, validating the usability of the method, are also presented and thoroughly discussed. Additionally, the paper includes a comparison of the efficacies obtained using the developed solution with the efficacies observed in the case of music notation generated by a musical instrument of a reputable brand, which clearly indicates the superiority of the proposed algorithm.

A Music Classification Approach Based on the Trajectory of Fifths

“…The trajectory of fifths, in turn, is formed with a series of the so-called Characteristic Points of the Music Signature (CPMS) obtained for consecutive fragments (dictated by the assumed time resolution) of a given composition. It is worth to notice that the concept of the music signature has already been used in simple and effective algorithms enabling recognition of the key signature [35] or the key of a given piece of music [11]. The music signature has also been utilized in the evaluation of the arrangement of compositions, e.g.…”

A Comparison of the Music Key Detection Approaches Utilizing Key-Profiles with a New Method Based on the Signature of Fifths

“…Key recognition methods based on key-profiles are much simpler [18,19,[33][34][35][36][37][38][39]. Keyprofiles generally assign larger weights to diatonic tones than to non-diatonic ones.…”

“…Although the algorithms for key detection based on key-profiles are among the simplest, their implementations can be cumbersome due to the necessity of a relatively large number of multiplication operations, especially in the case of electronic instruments (e.g., keyboards). A much simpler approach to the key-detection problem can be established utilizing the concept of the music signature, introduced in [35], which in this paper is referred to as the signature of fifths. We decided to change the name of this construct to emphasize its strong association with the circle of fifths.…”

“…We decided to change the name of this construct to emphasize its strong association with the circle of fifths. As shown in [35], a structural analysis of the signature of fifths enables the determination of the key of a piece of music. It is worth noting that one can also use this method to determine the key signature without the need for computation of any correlation coefficients [43].…”

“…As shown in [35], a structural analysis of the signature of fifths enables the determination of the key of a piece of music. It is worth noting that one can also use this method to determine the key signature without the need for computation of any correlation coefficients [43]. Observing the variations of the signature of fifths over time enables a "rough" evaluation of the harmonic structure of a given piece of music [44].…”