A Reproducible Evaluation of Hybrid Spectral–Temporal Features for Four-Class Respiratory Sound Event Classification
Respiratory-sound event classification is challenged by non-stationarity, class imbalance, heterogeneous acquisition, and participant-correlated recordings. This study evaluates whether direct fusion of short-time Fourier transform (STFT), mel-frequency cepstral coefficient (MFCC), and wavelet-packet features improves...