Speech emotion recognition using convolutional long short-term memory neural network and support vector machines

In this paper, we propose a speech emotion recognition technique using convolutional long short-term memory (LSTM) recurrent neural network (ConvLSTM-RNN) as a phoneme-based feature extractor from raw input speech signal. In the proposed technique, ConvLSTM-RNN outputs phoneme- based emotion probabilities to every frame of an input utterance. Then these probabilities are converted into statistical features of the input utterance and used for the input features of support vector machines (SVMs) or linear discriminant analysis (LDA) system to classify the utterance-level emotions. To assess the effectiveness of the proposed technique, we conducted experiments in the classification of four emotions (anger, happiness, sadness, and neutral) on IEMOCAP database. The result showed that the proposed technique with either of SVM or LDA classifier outperforms the conventional ConvLSTM-based one.