The maximum-likelihood estimate of a mixture model is usually found by using the EM algorithm. However, the EM algorithm suffers from the local-optimum problem and therefore we cannot obtain the potential performance of mixture models in practice. In the case of mixture models, local maxima often in
EM algorithms for Gaussian mixtures with split-and-merge operation
✍ Scribed by Zhihua Zhang; Chibiao Chen; Jian Sun; Kap Luk Chan
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 794 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0031-3203
No coin nor oath required. For personal study only.
✦ Synopsis
In order to alleviate the problem of local convergence of the usual EM algorithm, a split-and-merge operation is introduced into the EM algorithm for Gaussian mixtures. The split-and-merge equations are ÿrst presented theoretically. These equations show that the merge operation is a well-posed problem, whereas the split operation is an ill-posed problem because it is the inverse procedure of the merge. Two methods for solving this ill-posed problem are developed through the singular value decomposition and the Cholesky decomposition. Accordingly, a new modiÿed EM algorithm is constructed. Our experiments demonstrate that this algorithm is e cient for unsupervised color image segmentation.
📜 SIMILAR VOLUMES