Spherical Mapping of Short-Time Spectral Components

A spherical mapping approach is introduced to address the discontinuities of the phase spectrum obtained using the short-time Fourier transform (STFT). This approach maps complex-valued spectral components onto a three-dimensional spherical surface, and the spectral features are then represented by three direction angles defined by the mapped components relative to the three rectangular axes. By focusing on fundamental properties, the introduced and existing features are compared through nonlinear inter-feature correlation tests based on the maximal information coefficient (MIC). The results show that the redundant three-angle representations mitigate the trade-off between feature continuity and feature independence.