title: the map in label2rgb function
body: <p>I want to use the <code>label2rgb</code> function to construct a color image with a labeled image issued from a segmentation process. </p>
  
  <p>So I compute a color map <code>n</code>-by-3 which contain the meanvalue of each region detected in the segmentation. and I make this:</p>
  
  <pre><code>Lrgb = label2rgb(L, coul);
  </code></pre>
  
  <p>where <code>L</code> is tha labeled image, but I got this error:</p>
  
  <blockquote>
    <p>??? Error using ==> label2rgb>parse_inputs at 147<br>
    Invalid entry for MAP.</p>
    
    <p>Error in ==> label2rgb at 50 [label,map,zerocolor,order,fcnflag] =
    parse_inputs(varargin{:});</p>
    
    <p>Error in ==> test at 241 Lrgb = label2rgb(L, coul);</p>
  </blockquote>
  
  <p>Thank you,</p>