Active curve axis Gaussian mixture models

Gaussian Mixture Models (GMM) have been broadly applied for the fitting of probability density function. However, due to the intrinsic linearity of GMM, usually many components are needed to appropriately fit the data distribution, when there are curve manifolds in the data cloud. In order to solve this problem and represent data with curve manifolds better, in this paper we propose a new nonlinear probability model, called active curve axis Gaussian model. Intuitively, this model can be imagined as Gaussian model being bent at the first principal axis. For estimating parameters of mixtures of this model, the EM algorithm is employed. Experiments on synthetic data and Chinese characters show that the proposed nonlinear mixture models can approximate distributions of data clouds with curve manifolds in a more concise and compact way than GMM does. The performance of the proposed nonlinear mixture models is promising. 2005 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.