Mixture Normalization

Mixture Normalization is normalization technique that relies on an approximation of the probability density function of the internal representations. Any continuous distribution can be approximated with arbitrary precision using a Gaussian Mixture Model (GMM). Hence, instead of computing one set of statistical measures from the entire population (of instances in the mini-batch) as Batch Normalization does, Mixture Normalization works on sub-populations which can be identified by disentangling modes of the distribution, estimated via GMM.

While BN can only scale and/or shift the whole underlying probability density function, mixture normalization operates like a soft piecewise normalizing transform, capable of completely re-structuring the data distribution by independently scaling and/or shifting individual modes of distribution.