Add random Gaussian or Rician noise.

The noise level can be specified directly by setting the standard deviation or the desired signal-to-noise ratio for the Gaussian distribution. In the case of Rician noise sigma is the standard deviation of the two Gaussian distributions forming the real and imaginary components of the Rician noise distribution.

In anatomical scans, CNR values for GW/WM ranged from 5 to 20 (1.5T and 3T) for SNR around 40-100 (http://www.pallier.org/pdfs/snr-in-mri.pdf).

__init__(snr=None, sigma=None, noise_type='gaussian', seed=None)[source]¶

Init class.

Parameters

snr : float, default None

the desired signal-to noise ratio used to infer the standard deviation for the noise distribution.

sigma : float or 2-uplet, default None

the standard deviation for the noise distribution.

noise_type : str, default ‘gaussian’

the distribution of added noise - can be either ‘gaussian’ for Gaussian distributed noise, or ‘rician’ for Rice-distributed noise.

seed : int, default None

seed to control random number generator.