title: How to apply a filter in MATLAB?
body: <p>My question is how do I apply a 5×5 Laplacian filter with 8 at the center in MATLAB?</p>
  
  <p>I try this code but it does not work</p>
  
  <pre><code>kAvg = fspecial('average',[5 5]);
  kLap = fspecial('laplacian');
  </code></pre>