Manual Clean-up

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Once initial tracking is performed on all (or part) of your video, you can begin cleaning out tracking errors (if any). Automatic Refinement and Filtering should be applied after clean-up.

Cleaning up tracking gaps

Tracking errors usually happen in a few specific video frames and propagate to multiple subsequent frames, resulting in tracking gaps. Examples of problematic frames:

  • Occlusion (like one hand not visible in any of the cameras)
  • Indistinctive pose (like hands folded on chest).
  • Very fast motion with motion blur.

To clean up a sequence of incorrect frames (a tracking gap), you should use backward tracking:

Clean-up Steps
  1. Go toward the last frame of tracking gap, to a frame where actor pose is distinctive (no occlusion, no motion blur etc.).
  2. If necessary, use Rotate, Move and IK (Inverse Kinematics) tools to edit character pose to match actor pose on video.
  3. Turn off Trajectory Filtering (set it to zero) so that it does not interfere with your editing.
  4. Click Refit Pose button to get a better fit of character pose.
  5. Click Track Backward button.
  6. Stop backward tracking as soon as it comes close to the nearest good frame.
  7. If necessary, go back to remaining parts of tracking gap and use forward and backward tracking to clean them up.

Cleaning up individual frames

To clean up individual frames you should use a combination of editing tools (Rotate, Move and Inverse Kinematics) and Refit Pose button.

Note.png
Note: after Refit Pose operation iPi Mocap Studio automatically applies Trajectory Filtering to produce a smooth transition between frames. As the result, pose in current frame is affected by nearby frames. This may look confusing. If you want to see exact result of Refit Pose operation in current frame you should turn off Trajectory Filtering (set it to zero), but do not forget to change it back to suitable value later.

Tracking errors that cannot be cleaned up using iPi Studio

Not all tracking errors can be cleaned up in iPi Mocap Studio using automatic tracking and Refit Pose button.

  • Frames immediately affected by occlusion sometimes cannot be corrected. Recommended workarounds:
    • Manually edit problematic poses (not using Refit Pose button).
    • Record a new video of the motion and try to minimize occlusion.
    • Record a new video of the motion using more cameras.
  • Frames immediately affected by motion blur sometimes cannot be corrected. Recommended workarounds:
    • Manually edit problematic poses (not using Refit Pose button).
    • Edit problematic poses in some external animation editor.
    • Record a new video of the motion using higher framerate.
  • Frames affected by strong shadows on the floor sometimes cannot be corrected. Typical example is push-ups. This is a limitation of current version of markerless mocap technology. iPi Soft is working to improve tracking in future versions of iPi Mocap Studio.