Pulse Signal Processing And Its Application In Psychological Stress Tests

Psychological stress is an important factor that affects human health. When the psychological stress goes beyond the psychological endurance, it will cause diseases frequently and will badly influence people’s health. In real life, psychological stress affects people health of body and mind and has become the main factors affecting high quality life. Effective diagnosis and intervention of psychological stress needs to quantify the psychological pressure measurement, but subjective feelings and experience of outsiders can not accurately evaluate subjects’ psychological stress. It must be confirmed through biological signals assertively.The pulse,as an important biological signal, reflects the extent of psychological stress. This paper analyzes the difference of pulse signal in relaxed and stressed states. It combines the signal acquisition and processing methods with medical methods, and points out an idea of using pulse signals to analyze psychological stress degrees, and develops a psychological stress analysis system. The main research work includes:(1)Characteristics of the pulse signal were analyzed. As for the baseline drift, the surface signal and external noise interference issues, as well as imperfectness of hardware filtering in the acquisition process, it used wavelet transform and empirical mode decomposition(EMD) methods for filtering, respectively. The performance of wavelet, EMD, EEMD and CEEMD was compared. And the CEEMD method was employed for pulse signals filtering for its better performance.(2)According to the time-domain characteristics of the pulse signal, the peak, the slope and the threshold were used for pulse signal analysis. The three parameters were used simultaneously for signal detection to extract an intact pulse wave. Peak values and heartbeat intervals were calculated and normalized for the following data analysis of psychological stress degrees.(3)Through the analysis of the pulse signal and research on psychological pressure during the process of psychological stress, a pulse signal acquisition device with an embedded chip was designed. And a psychological stress test system was implemented. It can be used to acquire the pulse signal, transmit the data wirelessly and analyze the data. The effectiveness of using pulse signal for psychological stress tests and the accuracy of psychological stress index were verified with different methods.This paper developed a pulse signal acquisition device and a psychological stress test system, using pulse signals to reflect the psychological stress changes and to measure the psychological stress degrees. It can be applied in education, medical and other specific fields to objectively help doctors and patients to evaluate the psychological stress in order to assist doctors to diagnose and assist patients to recover.