title: How to improve speed of opencv fastNlMeansDenoising method?
body: <p>I am using opencv fastNlMeansDenoising for very small dot noise present in B&amp;W image.But It is taking more time(5 to 8 sec) to process an image(3306*4676).</p>
  
  <pre><code>public static BufferedImage despecklEffect(BufferedImage source){
  System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); 
  Mat sourceImage=ImageProc.img2Mat(source);
  Photo.fastNlMeansDenoising(sourceImage, sourceImage,50,7,21); 
  return ImageProc.mat2Img(sourceImage); }
  </code></pre>