Pressure Identification And Characteristic Comparison Analysis Based On HRV Signal

In modern society,more and more people are troubled by psychological stress,different levels of psychological stress will impact people in physical and psychological.In addition,a long period of psychological stress may also lead to depression,and bring people great pain and torture in physical and psychological.Therefore,how to accurately assess the level of people's stress,and therefore to take effective means of regulation is the focus of research in recent years.At present,the assessment of stress is mainly divided into two categories: stress assessment based on psychological questionnaire and stress assessment based on physiological parameters.The former is more easily quantifiable and easy to analyze,but it is often necessary for participants to respond positively and cope with individual subjective.The effect of this method is often considered to be unreliable.However,the physical response to psychological stress is divided into three steps: the nerve axis,neuroendocrine axis and endocrine axis.The stress response of the nervous system is the fastest and most directly.When human body is stimulated by psychological stress,the body's physiological balance will change,and will directly lead to changes in the physiological parameters of the human body,this change is subject to the autonomic nervous system and endocrine system dominated by the subjective control.Therefore,this paper proposes a heart rate variability signal to identify and evaluate the stress status of the human body.On this basis,we analyze the heart rate variability index which can reflect the autonomic nervous activity of the heart,and find out the changes in these indicators with stress changes,to detecte the degree of psychological stress conveniently,better to identify and evaluate the psychological stress.The main contents of this paper and the conclusions are devided into the following points:(1)According to the mental arithmetic task pattern,the experimental scheme of psychological pressure induced is designed,and the two indexes of the experiment and the performance of the experiment are analyzed,and the psychological pressure induced by the experiment is divided into three levels.(2)Preprocessing the collected raw ECG signals.In this paper,the wavelet transform method is used to remove the noise interference of ECG signal.After filtering the noise signal through the R wave positioning,extract the HRV(Heart Rate Variability)signal.The HRV features are extracted from the three domains of time domain,frequency domain and non-linearity,and the features are pre-processed on this basis.(3)The establishment of psychological stress three classification model.The SBS algorithm is used to construct the BP network model and the SVM classifier,which meet the experimental requirements.The feature sets with the highest contribution to the classification are selected from the original features extracted,and the classification accuracy of the two classifiers is determined by leaving a verification method The evaluation found that the recognition rate of the two classifiers was above 80%.(4)After the analysis of variance analysis,we analyze each feature of the feature set which does not depend on the two classifiers constructed in the fourth chapter to judge the significant difference level of each feature under different psychological stress.In order to find out,with the change of pressure degree,the law of the characteristic change,and its mechanism of neural activity analysis.In this paper,we have found that the psychological model of mental arithmetic can be induced by different time,and the SBS algorithm is used to construct the BP network model and the SVM classifier which meet the experimental requirements.The average recognition rate of SBS and the two classifiers is 80% or more,and the combination of the two kinds of classifiers is selected.Indicating that cardiac autonomic nervous activity can be a certain extent to distinguish between psychological stress.With the increasing of the pressure,the SDNN in the HRV index decreased significantly and the aHF was significantly increased.It was inferred that the sympathetic-vagal activity of the heart changed significantly with the increase of the pressure level,and the sympathetic nerve function was To a certain extent,inhibition of vagus nerve function is relatively excited.We can refer to the indicators of these changes in the degree of pressure on the detection and assessment.