Distance Measure Based on an Embedding of the Manifold of K-Component Gaussian Mixture Models into the Manifold of Symmetric Positive Definite Matrices
Amit Vishwakarma, KS Subrahamanian Moosath
TL;DR
This work develops a geometry-enhanced distance for K-component Gaussian Mixture Models by embedding their statistical manifold into the symmetric positive definite (SPD) matrix manifold. It proves the embedding is an isometric submanifold, derives a pullback metric that serves as a lower bound to the Fisher-Rao distance, and obtains a practical GMM distance via the affine-invariant SPD metric. The embedded manifold has dimension $\frac{K}{2}(n+1)(n+2)-1$, and the mapping is an embedding, becoming geodesic under fixed means and uniform mixing, with equality to the Fisher-Rao metric in that regime. Empirically, the approach yields state-of-the-art texture recognition accuracy on UIUC, KTH-TIPS, and UMD datasets, outperforming KL-based divergences and DPLM-based methods while maintaining computational efficiency.
Abstract
In this paper, a distance between the Gaussian Mixture Models(GMMs) is obtained based on an embedding of the K-component Gaussian Mixture Model into the manifold of the symmetric positive definite matrices. Proof of embedding of K-component GMMs into the manifold of symmetric positive definite matrices is given and shown that it is a submanifold. Then, proved that the manifold of GMMs with the pullback of induced metric is isometric to the submanifold with the induced metric. Through this embedding we obtain a general lower bound for the Fisher-Rao metric. This lower bound is a distance measure on the manifold of GMMs and we employ it for the similarity measure of GMMs. The effectiveness of this framework is demonstrated through an experiment on standard machine learning benchmarks, achieving accuracy of 98%, 92%, and 93.33% on the UIUC, KTH-TIPS, and UMD texture recognition datasets respectively.
