Wavelet-based colour texture retrieval using the kullback-leibler divergence between bivariate generalized Gaussian models

We study the retrieval of coloured textures from a database. In a statistical framework we model the heavy-tailed wavelet histograms through a generalized Gaussian distribution (GGD). We choose the Kullback-Leibler divergence (KLD) as a similarity measure and we obtain a closed-form expression for the KLD between two zero-mean bivariate GGDs. This allows us to take into account the rich correlation structure between the colour bands two by two. We show that this results in a considerably improved retrieval rate and, in addition, we demonstrate the superior performance of the bivariate GGD, in comparison with the bivariate Gaussian.