Design Of Blood Oxygen Signal Processing System Based On STM32

Blood oxygen saturation is the percentage of HbO2 integrated by oxygen in the total capacity of hemoglobin that can be integrated in the blood, which is the concentration of blood oxygen. It is an important physiological index of the human body, the accurate measurement of blood oxygen saturation is a prerequisite for the prevention of a variety of diseases, so it is very important in real-time monitoring of clinical care. In view of the inconvenience of carrying on a lot of blood oxygen measuring instrument, the design and research of blood oxygen signal processing system based on STM32 and AFE4400 is carried out in this thesis. The main contents of this thesis are as follows:1, Selection and implementation of blood oxygen signal processing algorithm based on STM32Compared with the commonly used blood signal processing algorithm, this thesis designs an improved blood signal processing algorithm which proposes a dynamic real-time R value extraction light intensity signal of the linear regression model, and determines the quantitative relationship between the regression coefficient B and the characteristics of R value, and its characteristics include good real-time, high accuracy, high data utilization rate, low data sampling rate and so on. The improved blood signal processing algorithm uses the IIR digital filter to filter the signal output by integrated analog front-end to reduce the noise.2, Design and implementation of blood oxygen system based on STM32The system design of this thesis uses STM32 as the main control part. At the same time, in the front-end circuit of signal processing, the TI company’s integrated core AFE4400 is used. Through the debugging of hardware circuit, the function of system design is realized, and the result of the system is displayed by the OLED display module.3, The effectiveness check of the systemThrough the comparison with the internationally used fluke index 2XL SpO2 simulation instrument and MEC-1000 monitor and after a preliminary verification, it is shown that the oxygen signal processing system designed in this thesis has some validity.The system in this thesis adopted the integrated analog front end AFE4400, which solved the problems of poor real-time, high noise and the poor results of signal processing that caused by signal processing front-end of traditional oxygen system’s using of simulated discrete components. In addition, a new feature extraction method adopted in the algorithm simplified the complexity of the program design, which makes it easier to obtain the saturation of blood oxygen saturation. The system’s adopting of integrated chip brought the advantages of small volume, low cost and easy portability. Therefore, this study achieved the rapidity, noninvasiveness, accuracy and portable measurement of blood oxygen saturation.