2pm, Thursday 21, September 2006
Statistical Modeling of Images with Fields of Gaussian Scale Mixtures

Siwei Lyu

The local statistical properties of photographic images, when represented in a multi-scale basis, have been described using scale mixtures of Gaussians (GSM). Here, we use this local description to construct a global field of Gaussian scale mixtures (FoGSM) model. Specifically, we model subbands of wavelet coefficients as a product of a homogeneous Gaussian Markov random field (hGMRF) and a second, exponentiated, hGMRF. We show that parameter estimation for FoGSM is feasible, and that samples drawn from an estimated FoGSM model have marginal and joint statistics similar to wavelet coefficients of photographic images. We develop an algorithm for image denoising based on the FoGSM model, and demonstrate significant improvements over current state-of-the-art denoising method based on the local GSM model.

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