Mutual information for quaternion time series

Abstract

Mutual Information method is a widely used method for estimation of time delay value in the process of time delay embedding. It’s designed for a univariate scalar time series. In the real systems often many outputs of investigated system are available. In this case a multivariate time delay estimation method is necessary if one may require to perform the uniform time delay embedding. The special case of multivariate data is a kinematic time series(e.g. quaternion time series or Euler angles time series). The main goal of this paper is to provide a method for this case: Mutual Information method’s extension for quaternion time series. The results are also compared with previosly presented quaternion’s angle method. The method was tested on the real kinematic data-the recordings of human gait.