Classifying autoregressive models using dissimilarity measures: A comparative study

Autoregressive (AR) models are used in various applications, from speech processing to radar signal analysis. In this paper, our purpose is to extract different model subsets from a set of two or more AR models. The approach operates with the following steps: firstly the matrix composed of dissimilarity measures between AR-model pairs are created. This can be based on the symmetric Itakura divergence, the symmetric Itakura-Saito divergence, the log-spectral distance or Jeffrey´s divergence (JD), which corresponds to the symmetric version of the Kullback-Leibler divergence. These matrices are then transformed to get the same properties as correlation matrices. Eigenvalue decompositions are performed to get the number of AR-model subsets and the estimations of their cardinals. Finally, K-means are used for classification. A comparative study points out the relevance of the JD-based method. Illustrations with sea radar clutter are also provided.