FT_WARP_APPLY
Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_warp_apply”.
FT_WARP_APPLY performs a 3D linear or nonlinear transformation on the input coordinates, similar to those in AIR 3.08. You can find technical documentation on warping in general at http://bishopw.loni.ucla.edu/AIR3 Use as [warped] = ft_warp_apply(M, input, method, tol) where M vector or matrix with warping parameters input Nx3 matrix with coordinates warped Nx3 matrix with coordinates method string describing the warping method tol (optional) value determining the numerical precision of the output, to deal with numerical round off imprecisions due to the warping The methods 'nonlin0', 'nonlin2' ... 'nonlin5' specify a polynomial transformation. The size of the transformation matrix depends on the order of the warp zeroth order : 1 parameter per coordinate (translation) first order : 4 parameters per coordinate (total 12, affine) second order : 10 parameters per coordinate third order : 20 parameters per coordinate fourth order : 35 parameters per coordinate fifth order : 56 parameters per coordinate (total 168) The size of M should be 3xP, where P is the number of parameters per coordinate. Alternatively, you can specify the method to be 'nonlinear', where the order will be determined from the size of the matrix M. If the method 'homogeneous' is selected, the input matrix M should be a 4x4 homogenous transformation matrix. If the method 'sn2individual' or 'individual2sn' is selected, the input M should be a structure based on nonlinear (warping) normalisation parameters created by SPM8 for alignment between an individual structural MRI and the template MNI brain. These options call private functions of the same name. M will have subfields like this: Affine: [4x4 double] Tr: [4-D double] VF: [1x1 struct] VG: [1x1 struct] flags: [1x1 struct] If any other method is selected, it is assumed that it specifies the name of an auxiliary function that will, when given the input parameter vector M, return an 4x4 homogenous transformation matrix. Supplied functions are 'translate', 'rotate', 'scale', 'rigidbody', 'globalrescale', 'traditional', 'affine', 'perspective', 'quaternion'. See also FT_WARP_OPTIM, FT_WARP_ERROR