A method of calculating the maximum-likelihood clustering for the unsupervised estimation of polynomial models for the data in images of smooth surfaces or for range data for such surfaces is presented. An image or a depth map of a region of smooth 3-D surface is modeled as a polynomial plus white noise. A region of physically meaningful textured-image such as the image of foliage, grass, or road in outdoor scenes or conductor or lintburn on a thick-film substrate is modeled as a colored Gaussian-Markov random field (MRF) with a polynomial mean-value function. Unsupervised-model parameter-estimation is accomplished by determining the segmentation and model parameter values that maximize the likelihood of the data or a more general Bayesian performance functional. Agglomerative clustering is used for this purpose.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>