Development Of The Visual Respiratory Auscultation System Based On STM32

The signal of respiratory sounds is a specific sound signal generated by the movement of air in the respiratory system of the human body,which contains a wealth of physiological and pathological information.Respiratory sounds are divided into two major categories: the normal respiratory sounds and the abnormal respiratory sounds.Normal respiratory sound is a sign of the health of the respiratory system.Abnormal respiratory sounds are of great importance to reflect respiratory diseases.The auscultation of respiratory sounds can not only diagnose respiratory diseases earlier and more accurate,but also facilitate operation and cause no harm to the human body.Limited by traditional stethoscope and the doctor’s clinical experience,it is not accurate to diagnose and judge respiratory disease by the traditional way of auscultation.Morevoer,it is more easily to be influenced by subjective factors.Therefore,developing a visual auscultation system which can extract respiratory sounds and display them accurately is of great significance.The visual respiratory auscultation system designed in this paper is based on STM32F103C8T6 chip as the control core.It consists of power module,sensor module,data processing module,storage module,display module and alarm module.The respiratory sound data collected by a professional respiratory sensor are putted into the AD/DC converter for analog-digital conversion and then processed by TMS320VC5509 A chip in real time.Under the control of a powerful STM32F103C8T6 chip,the processed data can be displayed on the color LCD screen in real time.It can also be stored in the SD card or converted to audio output.The system control part uses the real-time embedded operating system uC/OS-Ⅱ.The multi task management method not only simplifies the development task,but also makes the system software more stable and more convenient for maintenance.In order to achieve better man-machine interaction function,the 7 inch touchable serial interface screen is adopted,which achieves a more intuitive,clearer and more generous performance than the traditional LCD screen.With the use of memory cards,files can be set up for patients to facilitate follow-up treatment and disease data collection.The respiratory sound signals are easily disturbed by many aspects.The frequency of the heart sound signals overlaps with the respiratory sound,and the intensity of the signals is large,which has the greatest impact on the auscultation of respiratory sound.The traditional Fourier transform based filtering method is not suitable for overlapping frequency bands.In this paper,the wavelet analysis method with frequency local function is used to effectively remove the heart sound interference by using the different properties of the wavelet coefficients of the signal and noise on the scale,and the method of threshold de-noising.After the hardware and software debugging and the actual operation,this system can realize the visual auscultation function of the respiratory sound without infringing on the human body,and has the advantages of reliable function,simple operation,beautiful appearance and low cost.Under the circumstances of the prevention and control of respiratory diseases is still grim,the system can help doctors,especially grass-roots doctors,to effectively diagnose and prevent related respiratory diseases.The system will have a good use value and promotion value.