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Bug 2984 - Nonlinear normalisation distortions

Status NEW
Reported 2015-10-14 13:35:00 +0200
Modified 2015-10-14 13:35:21 +0200
Product: FieldTrip
Component: external
Version: unspecified
Hardware: PC
Operating System: Windows
Importance: P5 normal
Assigned to: Robert Oostenveld
Depends on:
See also:

Maité - 2015-10-14 13:35:21 +0200

Default parameters (flags) in Fieldtrip’s spm_normalise() are different from SPM’s spm_normalise(). In Fieldtrip, the amount of regularization is too low (= 0.1, line 144 in spm_normalise) compared with SPM’s default (=1). This also affects the computation of MNI-aligned individual grids because there is an implicit normalization step. Possible solutions: - Call/substitute Fieldtrip’s spm_normalise() by SPM’s function or change Fieldtrip’s default flags values. - Perform the normalization outside in SPM and provide the cfg.spmparams.flags. However, there is a bug in ft_volumenormalise() using that option.* Reported in another bug.