Estimation of slowly changing components of physiological signals

A method for the estimation of slowly changing components of physiological signals is presented in this communication. The method is based on a sequential approximation of slowly changing components by a low-order polynomial function. The polynomial coefficients are obtained by minimizing the distance between the expected zero crossing density (ZCD) value of the fast components of the physiological signal and the estimated ZCD value of these components. The method has been tested and preliminary results were satisfactory.