Real-time calculation of a limiting form of the Renyi entropyapplied to detection of subtle changes in scattering architecture

摘要

Previously a new method for ultrasound signal characterization using entropy Hf was reported, andit was demonstrated that in certain settings, further improvements in signal characterization could beobtained by generalizing to Renyi entropy-based signal characterization I_f(r)with values ofrnear2 (specifically r = 1.99) [M. S. Hughes et al., J. Acoust. Soc. Am. 125, 3141-3145 (2009)]. It wasspeculated that further improvements in sensitivity might be realized at the limit r→2. At that time,such investigation was not feasible due to excessive computational time required to calculate I_f(r)near this limit. In this paper, an asymptotic expression for the limiting behavior of If(r) as r→2 isderived and used to present results analogous to those obtained with I_f(1.99). Moreover, the limitingform I_(f,∞)is computable directly from the experimentally measured waveformf(t)by an algorithmthat is suitable for real-time calculation and implementation.