Blood vessel state evaluating device, blood vessel state evaluating method, and computer-readable recording medium storing blood vessel state evaluating program
A phase line tilt calculating unit (actual measurement) receives phase characteristics Pa(f) and Pb(f) outputted from frequency conversion units, and calculates phase difference characteristics of actual measurement based on a phase difference on each frequency component between the phase characteristics. A phase line tilt calculating unit (model) calculates phase difference characteristics between a transfer function Ga(f) and a transfer function Gb(f) calculated by a transfer function calculating unit, and outputs the calculated phase difference characteristics to a search unit. The search unit fits a variable k and determines a variable kopt (optimum solution) in which a tilt g(k) and a tilt gexp substantially match each other. The variable kopt is an index indicating a degree of arterial sclerosis of a subject.