title: OpenCV Dense feature detector
body: <p>I am using openCV to do some dense feature extraction. For example, The code </p>
  
  <pre><code>DenseFeatureDetector detector(12.f, 1, 0.1f, 10);
  </code></pre>
  
  <p>I don't really understand the parameters in the above constructor. What does it mean ? Reading the opencv <a href="http://docs.opencv.org/modules/features2d/doc/common_interfaces_of_feature_detectors.html#densefeaturedetector" rel="nofollow">documentation</a> about it does not help much either. In the documentation the arguments are:</p>
  
  <pre><code>DenseFeatureDetector( float initFeatureScale=1.f, int featureScaleLevels=1,
                            float featureScaleMul=0.1f,
                            int initXyStep=6, int initImgBound=0,
                            bool varyXyStepWithScale=true,
                            bool varyImgBoundWithScale=false );
  </code></pre>
  
  <p>What are they supposed to do ? i.e. what is the meaning of scale, initFeatureScale, featureScaleLevels etc ? How do you know the grid or grid spacing etc for the dense sampling.</p>