Document Type : Research Paper

Authors

• Rasta Sharafinejad ¹
• Soodeh Shadravan ²

¹ Department of Computer Engineering, Kerman Branch, Islamic Azad University, Kerman, Iran

² Department of Computer Engineering, Bardsir Branch, Islamic Azad University, Bardsir, Iran

Abstract

Emotions play an important role in human life. The design of systems capable of recognizing different emotions has been considered. To design the system, the DEAP database, which includes the physiological signals of EEG, ECG, EMG, and breathing rate recorded from 32 male and female participants, with the application of video music stimulation over a period of 120 minutes, has been used. For every minute, labelling is done based on a face video review by an expert. Four classes were considered for emotions: anger, happiness, sadness and satisfaction. In the first stage of system implementation, EEG signals obtained by the DEAP method with a sampling rate of 512 Hz are subject to noise removal and filtering. For this purpose, two filtering stages are performed, one in the frequency domain and the other in the time-frequency domain. To remove noise with unknown signal sources, time-frequency domain filtering (wavelet transform) with default coefficients of MATLAB software is used. In the next step, the alpha, beta, and gamma sub-bands of the EEG signal are extracted based on the detail and general coefficients of the Daubechies wavelet transform with four or eight decomposition levels. Then the signal is reconstructed with the desired coefficients. Linear and dynamic features are extracted from the alpha, beta and gamma sub-bands of the EEG signal. By determining the desired features, the extracted features are applied in the first step as input to common classification methods such as decision tree, nearest neighbour and support vector machine, and in the next step, they are applied as input to the convolutional deep learning network. Also, in a review, EEG signals are considered as input for deep classification structure. The goal is to evaluate the results of deep learning networks and other methods for emotion classification. According to the obtained results, the support vector machine method achieved the highest classification accuracy for identifying four emotional states with 94.1% accuracy. Also, the proposed convolutional neural network identified the desired emotional states with 80% accuracy. The performance of the deep learning network will be improved if more features are used; In addition, the deep learning method has significant advantages over simple classification methods due to being resistant to noise and automatic processing.

Keywords

• Emotion quantification
• vital bio potentials
• wavelet transform
• principal component analysis
• intelligent classifiers