Bayesian Filter for Sound Environment by Considering Additive Property of Energy Variable and Fuzzy Observation in Decibel Scale - Introduction of Fuzzy Moments

摘要

In the measurement and evaluation of actual random signal in a sound environment, the observed data often contain the fuzziness due to several causes. Furthermore, there exists usually a background noise in addition to the objective specific signal. In this study, a Bayesian filter for estimating a specific signal, based on the observed data containing the fuzziness, and the effects of a background noise with non-Gaussian type is proposed. More specifically, after paying attention to the energy variables satisfying the additive property of the specific signal and background noise, by introducing a new type of membership function with unknown parameter, which is suitable for the energy variable and the observation in decibel scale, a state estimation method is theoretically derived. In the proposed estimation algorithm, the parameter of the membership function is estimated simultaneously with the specific signal based on the fuzzy observation data. The proposed theory is applied to the actual observation data in a sound environment, and its usefulness is experimentally verified.