Correlation matrix interpolation in Sound Source Localization for a robot

In microphone array processing, a Correlation Matrix (CM) between multiple channel input signals is widely utilized for various purposes such as Sound Source Localization (SSL), etc. The CM corresponds to spatial information between a microphone and a sound source, and it dynamically changes as they move in a dynamic environment. Since pre-measured CMs have difficulties in dealing with dynamically changing environments due to their discreteness, this paper addresses a CM interpolation utilizing a few discrete known CMs. The proposed method is based on an integration of eigen-value-scaling and linear interpolation, which requires a few measurements and low computational costs. Apart from conventional methods, this paper deals with an interpolation based on a correlation-matrix not based on a transfer-function, which achieves the integration approach. The evaluation shows better estimation performance compared to conventional transfer-function-based methods. We also applied the interpolation to SSL and confirmed its validity.