Design Of Mental Relaxation VR Scenes And Study Of Relaxation State Model Based On Forehead EEG Features

The acceleration of the social rhythm leads to a sharp increase in psychological problems caused by stress.Different from the traditional psychological relaxation methods using images,audios and videos,virtual reality is more immersive.Virtual reality system and virtual environment affect the relaxation effect of users through more immersive and realistic audiovisual scenes.As a central neurophysiological signal,EEG(electroencephalogram)is closely related to the state of psychological relaxation.And EEG is often used for emotion recognition because of its convenience,low cost and high accuracy.At present,there are several limitations in the study of psychological relaxation.First of all,traditional materials such as pictures and audio are inefficient in inducing emotions effectively and are more susceptible to interference from environmental factors.Secondly,at present,the effect evaluation of relaxation materials is limited to the subjective scale evaluation,with large individual differences.While the evaluation of the psychological relaxation state based on EEG lacks a more systematic model.In view of the above problems,this paper carries out the following three main tasks:1.Design and product “Virtual Reality relaxation scenes”,including 4 VR scenes combining different audio-visual content.By creating a simulated environment in the virtual reality system,the subjects' emotions can be adjusted to a normal state to comfort the subjects and relieve their psychological pressure.In the production of the scene,the video of real scenery tourism and sightseeing is selected as the stimulus material,combining western classical music and new century music which are gentle melody,light rhythm and no difference in lyrics.The SAM assessment and self-evaluation of the subject's relaxation degree of 33 subjects in each relaxation scene were calculated.The experimental results show that each scene is located near the neutral positive emotion in the three-dimensional emotional coordinates of PDA,and the score of relaxation self-evaluation is 6.5-8.It provides materials for subsequent EEG signal acquisition and model construction.2.Obtain EEG signal features that are highly correlated with psychological relaxation.The frontal EEG features of the subjects during the whole relaxation process were extracted and analyzed.By using the fast Fourier transform get five rhythm signal spectrum,then analysis and comparison of energy,energy ratio,Root mean square of frequency,frequency symmetry,and Shannon entropy,energy entropy.A comparative analysis was made of the significant differences,trends and concentrations of the prefrontal EEG features in the two stages before and after viewing the relaxation scene.Finally,the features with obvious differences(p<0.05 account for more the 40%)and strong consistency of the trend(the same trend change accounted for more than 70%)were selected as the most relevant signal characteristics with psychological stress.3.Construct the psychological stress assessment model.Think of relaxation emotion recognition as a regression problem,based on the characteristics of emotion recognition,the psychological stress evaluation feature is obtained.In combination with the final selected prefrontal EEG features that are most relevant to psychological pressure as the relaxation model parameters.The features with different change trends are respectively placed in the numerator and the denominator by referring to the linear regression model,and the loss function of the model is optimized by the gradient descent algorithm.Combine Genetic Algorithm(GA)to optimize the optimal set of function parameters among the initial values,after verifying the effect of the model after training,it was finally found that there was an obvious increasing trend of relaxation degree in the process of watching the relaxation scene in the verification set.Based on virtual reality technology,this paper studies psychological relaxation from a new perspective,providing a more immersive and realistic way to induce psychological relaxation.Furthermore,the model of psychological stress assessment is proposed to provide theoretical support for the production of more relaxation scenes in the field of psychological relaxation therapy.