Modified Sub-Harmonic Summation method for Time-Frequency analysis in melody extraction

This research proposes a novel Time-Frequency (T-F) analysis method which has made some modifications to the Normalized Sub-Harmonic Summation (NSHS) method. We also have tracked the problems of NSHS and observed 4 main characteristics of music signals. As a result, we proposed the Modified Sub-Harmonic Summation (MSHS) method and introduced the Fundamental-to-Overtone Magnitude Ratio (FOMR) to solve the observed problems. The method made 3 modifications to the NSHS method: using a frequency adaptive weighting function, applying the shiftable frequency range to the ideal harmonic positions and adding a masking function. The proposed MSHS method yields better results compared to the NSHS method when applying the MSHS method with an appropriate masking function. The proposed method also gives good results for melody extraction since it aims to emphasize salient pitches and deemphasize the rest.