You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cat_main_gintnormi.m
    path of file: ./repos/cat12
    
    the code of the file until where you have to start completion: function Ysrc = cat_main_gintnormi(Ym,Tth)
% cat_main_gintnormi
% ______________________________________________________________________
% 
% Inverse function of cat_main_gintnorm that restore the original 
% intensity levels of an intensity normalized image Ym. 
%
%   Ysrc = cat_main_gintnormi(Ym,Tth)
% 
%   Ysrc .. image with original intensity levels
%   Ym   .. intensity normalized image
%   Tth  .. data structure with the intensiy transformation
%
% Example:
%  % old values in the original image Ysrc
%  Tth.T3thx = [BGth CSFth GMth WMth WMth+diff([GMth,WMth]) ]; 
%  % new values of the output images of the tresholds Tth.T3thx
%  Tth.T3th  = 0:1/3:4/3;                                      
%  % div by 3 due to old definitions
%  Ym = cat_main_gintnormi(Ysrc/3,Tth); 
% ______________________________________________________________________
%
% Christian Gaser, Robert Dahnke
% Structural Brain Mapping Group (https://neuro-jena.github.io)
% Departments of Neurology and Psychiatry

    
function Ysrc = cat_main_gintnormi(Ym,Tth)
% cat_main_gintnormi
% ______________________________________________________________________
% 
% Inverse function of cat_main_gintnorm that restore the original 
% intensity levels of an intensity normalized image Ym. 
%
%   Ysrc = cat_main_gintnormi(Ym,Tth)
% 
%   Ysrc .. image with original intensity levels
%   Ym   .. intensity normalized image
%   Tth  .. data structure with the intensiy transformation
%
% Example:
%  % old values in the original image Ysrc
%  Tth.T3thx = [BGth CSFth GMth WMth WMth+diff([GMth,WMth]) ]; 
%  % new values of the output images of the tresholds Tth.T3thx
%  Tth.T3th  = 0:1/3:4/3;                                      
%  % div by 3 due to old definitions
%  Ym = cat_main_gintnormi(Ysrc/3,Tth); 
% ______________________________________________________________________
%
% Christian Gaser, Robert Dahnke
% Structural Brain Mapping Group (https://neuro-jena.github.io)
% Departments of Neurology and Psychiatry
% Jena University Hospital
% ______________________________________________________________________
% $Id$


  % RD202102: There should be no inversion but in the test-retest of
  %           Buchert sanon-102748-00003-00001-1 it happend