We present two unsupervised segmentation algorithms based on hierarchical M
arkov random held models for segmenting both noisy images and textured imag
es. Each algorithm finds the the most likely number of classes, their assoc
iated model parameters and generates a corresponding segmentation of the im
age into these classes. This is achieved according to the maximum a posteri
ori criterion. To facilitate this, an MCMC algorithm is formulated to allow
the direct sampling of all the above parameters from the posterior distrib
ution of the image. To allow the number of classes to be sampled, a reversi
ble jump is incorporated into the Markov Chain. Experimental results are pr
esented showing rapid convergence of the algorithm to accurate solutions. (
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