title: Fanelli face detection - PCL code vs. author's implementation
body: <p>I am currently working with ASUS Xtion on the extraction of the face ROI in a depth+color stream. 
  At the moment, I am manually grabbing the frames with OpenNI2 instead of using the PCL wrappers. </p>
  
  <p>After grabbing the depth map I am generating the point cloud in a cv::Mat and a pcl::PointCloud format, respectively, to run Fanelli's decision forest method twice, once with the implementation which Fanelli provides himself (<a href="http://www.vision.ee.ethz.ch/~gfanelli/head_pose/head_forest.html" rel="nofollow">http://www.vision.ee.ethz.ch/~gfanelli/head_pose/head_forest.html</a>) and once with the PCL version of that method. </p>
  
  <p>Fanelli's code performs "normal", i.e. regarding execusion time and detection rate. However, when I'm feeding my pcl::PointClouds to the PCL forest I hardly get detected heads and the execusion times are quite slow. </p>
  
  <p>Has anyone else already been doing a comparison between those two implementations (of the same method!)? 
  I am trying to figure out the differences between them, besides data representation and the existing forest that come with each method respectively (however, the forests were trained on the same DB!).</p>
  
  <hr>
  
  <p>Basically, I am doing it like this:</p>
  
  <pre><code>&lt;grab frames with OpenNI2 library&gt;
  &lt;call processNewFrame method of a frame processing class&gt;
  </code></pre>
  
  <p>withing that processNewFrame method:</p>
  
  <pre><code>&lt;convert float[] depthmap into cv::Mat and pcl::PointCloud&lt;pcl::PointXYZRGB&gt; pointcloud&gt;
  CRForestEstimator-&gt;estimate(..., cv::Mat pointcloud, ...)
  pcl::RFFaceDetectorTrainer-&gt;setInputCloud(PointXYZ version of pointcloud)
  pcl::RFFaceDetectorTrainer-&gt;detectFaces()
  </code></pre>
  
  <p>That frame processing class initializes the CRForestEstimator (class has pointer as member) as well as the pcl::RFFaceDetectorTrainer (class has "normal" member variable) in its constructor according to provided sample code.</p>