title: Undefined Reference, DisparityBilateralFilter in OpenCV using CUDA
body: <p>I'm a beginner with OpenCV and CUDA so sorry, if this Question is trivial.
  I've installed CUDA 9.0 with, OpenCV 3.3.1 and I'm using Qt 5.</p>
  
  <p>I try to filter a disparity map with cuda::DisparityBilaterFilter. Unfortunately It's not working.</p>
  
  <p>Code Example:</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include "opencv2/opencv.hpp"
  #include "opencv2/ximgproc.hpp"
  #include "opencv2/cudastereo.hpp"
  
  using namespace cv;
  
  int main()
  {
      int nDisp = 64;
      int radius = 3;
      int iters = 1;
      Ptr&lt;cuda::DisparityBilateralFilter&gt;  pCudaBilFilter = cuda::createDisparityBilateralFilter(nDisp, radius, iters);
  
  //    pCudaBilFilter-&gt;apply(DispMapInp, LeftImages, filteredDispMap);
  
      return 0;
  }
  </code></pre>
  
  <p>I'm getting en error:</p>
  
  <pre><code>error: undefined reference to `cv::cuda::createDisparityBilateralFilter(int, int, int)'
  </code></pre>
  
  <p>Other OpenCV Code (like StereoMatching) is working fine. What am I missing? I'm sure it's a stupid mistake.</p>
  
  <p>Thanks in advance.</p>