Signal Process Of Ankle Brachial Index

With the improvement of the living level and the transformation of the living styles, vascular disease has become one of the major diseases that threat the survival and quality of life of all human beings. The Ankle-Brachial Index (ABI) is a vital index of the cardiovascular events and it is possible to diagnose the cardiovascular diseases in the early stage via the measurement of ABI. The research of ABI signal acquisition, process and analysis has attracted more and more attention by the medical workers in the world. In this paper, the key point is to find the start point of pulse wave corresponding to the shrinkage pressure, and the difficult point is noise decrease signal process algorithm of pulse wave, finally to realize finding start point of pulse wave and measurement of shrinkage pressure by software, and provide dependable data for the measure of ABI.First, the subject analyze on the application of wavelets transformation on biomedical signal process, and bring the method to the noise decrease of pulse wave. The pulse wave including shrinkage pressure which modulated by breath signal is shown as the irregular wave, and the resistance variation formed by the breath interfere the observation on the variation of pulse resistance. Adopting the method of combination with Mallat and graphics display algorithms, it is realized separation between respiratory signal and pulse wave including shrinkage pressure by simulation on MATLAB, to eliminate disturbance of pulse resistance including shrinkage pressure by respiratory movement.For realizing the development of practical software, this paper analyze the advantages and disadvantages of methods between VB and MATLAB, mainly study a method of calling COM component in VB and principle of data exchange between them; using the function of Matlab Builder for .NET, change the M file which used to reduce the noise of pulse wave compiled in MATLAB to COM component; using Visual Basic language program and call the component, develop a wavelet reducing noise software completely abscising MATLAB.Though the signal reduced the noise is not modulated by the breath, the wave is varying before first wave trough of resistance signal occurred. This paper realize the research on waveform start point by adopting waveform recognition algorithm and selection rule, and then add the algorithm to wavelet COM component. Finally it is realized automatic measurement of shrinkage pressure by using Visual Basic program, so as to provide effective way to accurately measure of ABI.