Recognizing Emotions from Whispered Speech Based on Acoustic Feature Transfer Learning

Whispered speech, as an alternative speaking style for normal phonated (non-whispered) speech, has received little attention in speech emotion recognition. Currently, speech emotion recognition systems are exclusively designed to process normal phonated speech and can result in significantly degraded performance on whispered speech because of the fundamental differences between normal phonated speech and whispered speech in vocal excitation and vocal tract function. This study, motivated by the recent successes of feature transfer learning, sheds some light on this topic by proposing three feature transfer learning methods based on denoising autoencoders, shared-hidden-layer autoencoders, and extreme learning machines autoencoders. Without the availability of labeled whispered speech data in the training phase, in turn, the three proposed methods can help modern emotion recognition models trained on normal phonated speech to reliably handle also whispered speech. Throughout extensive experiments on the Geneva Whispered Emotion Corpus and the Berlin Emotional Speech Database, we compare our methods to alternative methods reported to perform well for a wide range of speech emotion recognition tasks and find that the proposed methods provide significant superior performance on both normal phonated and whispered speech.