split4dTo3d.m

function files = split4dTo3d(fname)
% FORMAT files = split4dTo3d(fname)
%
% Splits a 4D nifti file into a series of 3D nifti files. Needs SPM
% functions to work. If input file is fdata.nii, the output files will have
% filenames like fdata_001.nii, fdata_002.nii, etc.
% Written by "baggy" 20111112.

if (nargin < 1)
    [fname, sts] = spm_select;
    if (sts == 0)
        fprintf('split4dTo3d: Operation cancelled.\n');
        return
    end
end

vol = spm_vol(fname);
img = spm_read_vols(vol);
sz = size(img);

tvol = vol(1);
tvol = rmfield(tvol, 'private');
tvol.descrip = 'generated by split4dTo3d.m';

[dn, fn, ext] = fileparts(fname);

for ctr = 1:sz(4)
    tvol.fname = sprintf('%s%s%s_%.3d%s', dn, filesep, fn, ctr, ext);
    files{ctr} = tvol.fname;
    spm_write_vol(tvol, img(:, :, :, ctr));
end
end