function outpoints = tal2icbm_fsl(inpoints)
%
% This function converts coordinates from Talairach space to MNI
% space (normalized using the FSL software package) using the 
% tal2icbm transform developed and validated by Jack Lancaster 
% at the Research Imaging Center in San Antonio, Texas.
%
% http://www3.interscience.wiley.com/cgi-bin/abstract/114104479/ABSTRACT
% 
% FORMAT outpoints = tal2icbm_fsl(inpoints)
% Where inpoints is N by 3 or 3 by N matrix of coordinates
% (N being the number of points)
%
% ric.uthscsa.edu 3/14/07

% find which dimensions are of size 3
dimdim = find(size(inpoints) == 3);
if isempty(dimdim)
  error('input must be a N by 3 or 3 by N matrix')
end

% 3x3 matrices are ambiguous
% default to coordinates within a row
if dimdim == [1 2]
  disp('input is an ambiguous 3 by 3 matrix')
  disp('assuming coordinates are row vectors')
  dimdim = 2;
end

% transpose if necessary
if dimdim == 2
  inpoints = inpoints';
end

% Transformation matrices, different for each software package
icbm_fsl = [0.9464 0.0034 -0.0026 -1.0680
		   -0.0083 0.9479 -0.0580 -1.0239
            0.0053 0.0617  0.9010  3.1883
            0.0000 0.0000  0.0000  1.0000];

% invert the transformation matrix
icbm_fsl = inv(icbm_fsl);

% apply the transformation matrix
inpoints = [inpoints; ones(1, size(inpoints, 2))];
inpoints = icbm_fsl * inpoints;

% format the outpoints, transpose if necessary
outpoints = inpoints(1:3, :);
if dimdim == 2
  outpoints = outpoints';
end