title: Stereocalibration + Rectification in OpenCV
body: <p>I'm doing a stereovision setup, with 2 cameras mounted above a wing. The left camera is tilted a few degree inwards while the right camera in parallel with the wing. All images available <a href="https://umich.box.com/opencvquestion" rel="nofollow">here</a></p>
  
  <p>Then using (cut and pasted, but does not compile as is)</p>
  
  <pre><code>// performing stereocalibration given imagePoint_leftcamera and rightcamera
  Flea3.reproj_error = stereoCalibrate(objectPoints,imagePoints_left,imagePoints_right,cameraMatrix_left,
          distCoeffs_left,cameraMatrix_right,distCoeffs_right,imageSize, Flea3.R, Flea3.T, Flea3.E, Flea3.F,
          TermCriteria(CV_TERMCRIT_ITER+CV_TERMCRIT_EPS, 100, 1e-5),
          CV_CALIB_FIX_INTRINSIC );
  
  // Peform stereorectification
  stereoRectify(cameraMatrix_left, distCoeffs_left, cameraMatrix_right, distCoeffs_right, imageSize, Flea3.R, Flea3.T, Flea3.R1, Flea3.R2, Flea3.P1, Flea3.P2, Flea3.Q, CALIB_ZERO_DISPARITY, -1, Size(), &amp;Flea3.validRoi_left, &amp;Flea3.validRoi_right);
  
  //computes undistort and rectify maps
  initUndistortRectifyMap(cameraMatrix_left, distCoeffs_left, R1, P1, imageSize, CV_16SC2, rmap[0][0], rmap[0][2]);
  initUndistortRectifyMap(cameraMatrix_right, distCoeffs_right, R2, P2, imageSize, CV_16SC2, rmap[1][0], rmap[1][3]);
  
  remap(src_left, img_left, rmap[0][0], rmap[0][4], CV_INTER_LINEAR);
  remap(src_right, img_right, rmap[1][0], rmap[1][5], CV_INTER_LINEAR);
  </code></pre>
  
  <p>Shouldn't the black region be on the right in the right image? Since the right camera should be tilted right?</p>
  
  <p>Also, the ROI (denoted by red box) is clearly wrong, though the stereorectification appears to work!</p>
  
  <p>Is my calibration any good? BTW my re-projection error returned by cv::stereocalibrate is 0.6004</p>