RESUMEN
Lung electrical impedance signal carries the information of hemodynamics such as pulmonary blood supply intensity, vessel elasticity, blood flow resistance and so on. It can be used to diagnose and distinguish various kinds of heart diseases and to judge cardiac functions. The character points of lung impedance are the main basis to analyze the information of hemodynamics. This article is based on wavelet transformation to extract the character points of lung impedance. First we used the scale waveform of character points of lung impedance to make the template. Then we got wavelet ratio wave form from lung impedance by wavelet transformation. Finally we used the wavelet ratio wave form to do matching operation with the template in order to locate character points. The result of experiment demonstrates that it is an efficient and feasible method to locate character points by wavelet transformation because of its strong real time and high detection efficiency.