title: Using PCL(point cloud library) to obtain an array of an object information
body: <p>As an example, in a 2D space, a position of a square is presented by the set of '1's and a position of empty space is presented by the set of '0's like</p>
  
  <pre><code>00000000000000
  00000111000000
  00000111000000
  00000111000000
  00000000000000
  </code></pre>
  
  <p>It is found that pcl::OrganizedFastMesh class is a way to do this task. The website of <a href="http://docs.pointclouds.org/trunk/classpcl_1_1_organized_fast_mesh.html" rel="nofollow noreferrer">http://docs.pointclouds.org/trunk/classpcl_1_1_organized_fast_mesh.html</a> shows the details of the class, however, it is very difficult to understand to me. For example, if the input file name is 'example.stl', how to obtain the above '0's and '1's information to an array 'siteInfo[][]'?</p>