1. A method, performed by a processor, the method comprising: measuring a cross sectional area of an arterial segment and a volumetric flow rate of blood flowing through the arterial segment at two or more locations; estimating a compliance transfer function for the arterial segment by the processor using measured minimum, maximum and mean values of blood pressure; deriving a transmission line model of the arterial segment by the processor based on the cross sectional area of the arterial segment at the two or more locations as scaled by the compliance transfer function and the volumetric flow rate of blood at the two or more locations; and computing, by the processor, the blood viscosity based on the transmission line model.