COMPARISON OF KULLBACK-LEIBLER DIVERGENCE APPROXIMATION METHODS BETWEEN GAUSSIAN MIXTURE MODELS FOR SATELLITE IMAGE RETRIEVAL

In many applications, such as image retrieval and change detection, we need to assess the similarity of two statistical models. As a distance measure between two probability density functions, Kullback-Leibler divergence is widely used for comparing two statistical models. Unfortunately, for some models such as Gaussian Mixture Model (GMM), Kullback-Leibler divergence has no analytically tractable formula. We have to resort to approximation methods. In this paper, we compare seven methods, namely Monte Carlo method, matched bond approximation, product of Gaussian, variational method, unscented transformation, Gaussian approximation, and min-Gaussian approximation, for approximating the Kullback-Leibler divergence between two Gaussian mixture models for satellite image retrieval. Two image retrieval experiments based on two publicly available datasets have been performed. The comparison is carried out in terms of both retrieval performance and computational time.