| With the aging of the population,nearly forty percent people worldwide die of cardiovascular disease each year.Cardiovascular disease has become the first major disease threatening human health.The prevention and detection of cardiovascular disease has become more and more important.However,the traditional medical monitoring equipment is large in volume and complicated in operation,so it is not suitable for domestic use.Electrocardiogram,respiration,blood oxygen and pulse are several important physiological parameters of human body.Therefore,the design of multi-physiological parameters monitoring system suitable for household use has high application value and social benefits.The multi-physiological parameters monitoring system designed in this thesis is mainly divided into two parts,one is the multi-physiological parameters acquisition and data transmission module,the other is the data processing and display module on the smart Android mobile phone.Because the data collected from the analog front-end chip is more reliable and accurate than the data collected by the discrete components,the analog front-end chip ADS1292 R and AFE4400 are used in the data acquisition part of the system.The low-power microcontroller controls the chips and transmits data by Bluetooth.The data processing and display are implemented on the mobile phone.At present,Bluetooth function is the standard configuration of smart phone,so Bluetooth technology is the most convenient transmission mode,which also makes the system design more versatile.For the part of noise processing and eigenvalue detection of physiological signal.In the part of ECG,biorthogonal quadratic B-spline wavelet transform was used to decompose the ECG signal with 4-scale wavelet transform,and the Myoelectric noise and power line interference filtering of ECG signal was realized by combining the soft and hard threshold denoising.A fullpass reduced low-pass filter was used to remove the baseline drift and the wavelet coefficient mode-extremum pair was used to extract the localization QRS wave.In the treatment of respiratory signal and the calculation of respiration rate,the integer coefficient digital filter with less calculation amount was designed,and the calculation of respiration rate was accomplished by zerocrossing counting method.For the noise processing of pulse wave signal,5-point smoothing filter was used to filter the high frequency interference,an improved fast median filter was used to filter baseline drift,and the peak and trough of pulse wave signal were identified by differential threshold method.Thus,the characteristic value of blood oxygen was obtained.The pulse rate can be obtained from the detected wave peak of the infrared light pulse wave.The Android mobile phone client draws the filtered ECG and pulse wave,and displays the corresponding physiological signal on the interface.Experiments have shown that the multi-physiological parameters monitoring system designed in this paper can collect and display ECG,respiration,blood oxygen and pulse signal.The absolute deviation of heart rate and pulse rate is less than 2 times / min,the deviation of respiration rate is less than 3 times / min,and the relative error of blood oxygen is less than 2%.The system has the advantages of small volume,simple operation and low price.It is very suitable for household and has practical significance for the prevention and monitoring of cardiovascular disease. |
