title: Threshold for matches in OpenCV's DescriptorMatchers
body: <p>is there a way to set a threshold for potential matched pairs of image descriptors calculated by DescriptorMatcher in OpenCV's features2d?</p>
  
  <p>In detail, I have a Bruteforce-Matcher with which I want to calculate descriptor pairs of two images and only pairs with a minimum distance of <em>threshold</em> should go in matches.</p>
  
  <pre><code>BFMatcher matcher(NORM_L2, true);
  vector&lt;DMatch&gt; matches;
  matcher.match(descriptors1, descriptors2, matches);
  </code></pre>
  
  <p>Thank's for your help!</p>