erSteerable( theta ) </strong></div>

<h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre class="comment"> Steerable 2D Gaussian derivative filter (for visualization).

 This function is a demonstration of steerable filters.  The directional
 derivative of G in an arbitrary direction theta can be found by taking a
 linear combination of the directional derivatives dxG and dyG.

 USAGE
  filterSteerable( theta )

 INPUTS
  th