Noise estimator for SENSE MRI

The method accurately estimates the non-stationary parameters of noise from just a single acquisition of a SENSE magnitude MR image. The algorithm assumes that the noise follows a non-stationary Rician distribution and it makes use of a homomorphic separation of the spatially variant noise in two terms: a stationary noise term and one low frequency signal. The non-stationary variance of noise is then estimated by a low pass filtering with a Rician bias correction.
The algorithm was proposed in:
Spatially variant noise estimation in MRI: A homomorphic approach, S Aja-Fernández, T Pieciak, G Vegas-Sánchez-Ferrero, Medical Image Analysis, 2014