title: OpenCV - Correctly recoverPose after findEssentialMat
body: <p>I have <em>correct</em> correspondances between consecutive frames, and need to estimate the transformation between them to generate a trajectory. The following C++ pipeline, the generated trajectory goes no sense.</p>
  <pre><code>auto EssentialMatrix = cv::findEssentialMat(points_previous,
                                              points_current, 
                                              camera_focal_length, 
                                              camera_principal_point,
                                              cv::RANSAC, 
                                              0.999, 
                                              1.0, 
                                              mask);
  
  auto inliers = cv::recoverPose(EssentialMatrix, 
                  points_previous, 
                  points_current, 
                  CameraMatrix, 
                  R, 
                  t, 
                  mask);
  
  t_pos_ = t_pos_ + 1.0 *(R_pos_*t);  
  R_pos_ = R * R_pos_;             
  </code></pre>
  <p>So, my question is: how to <em>correctly</em> recover the transformation between two consecutive frames with C++ OpenCV utilities? Are additional steps needed to do so?</p>