 <p>MATLAB is regularly updated with new functions, and there are also multiple toolboxes (with their own updates). So the functions you can use depends on your version of MATLAB. Unfortunately it is not easy to find out in which version of MATLAB a function first became available.</p> <p>You can use these functions to get some more information:</p> <p><code>ver</code> - to see what MATLAB version you have and which which toolboxes you have access to.</p> <p><code>which</code> - to see if a particular function is on your MATLAB path</p> <p>e.g. <code>which imguidedfilter</code> will show you if you have access to the function <code>imguidedfilter</code>.</p> <p>This particular function appears to be a very new function which you may need R2014a for (as I have R2013b and Image Processing Toolbox and don't have it).</p>