Analysing Manual 3D Tracks
 
 
 

The manual 3D tracking process computes the camera properties and reconstructs the 3D coordinates of the 2D points that are tracked in the Stabilizer. The manual 3D tracking analysis also calculates the tracking coordinates of the two references frames, the keyframes, and all the frames in the clip.

Most errors result from a poorly tracked clip in the Stabilizer or when coordinates are set incorrectly.

Use the Analysis menu to finalize the manual 3D tracking process by fine-tuning the trackers. To access the Analysis menu, click Analysis.

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The Analysis controls are described as follows.

Track Camera buttonTracks the 3D track points and processes the 3D tracking result.

Residual columnDetermines the difference in pixels between the 2D track and the calculated 3D track for each tracker in the clip sequence.

The value shown in the Residual column represents the difference in precision between the 2D track and the 3D track at the current frame.

Average columnShows the average residual of the tracker over all frames in the clip.

CurResidual fieldShows the average residual of the selected tracker at the current frame.

Tracker columnRepresents each tracker in the Stabilizer and each track point in the 3D tracking scene.

Enabled buttonActivates or deactivates the tracker in the scene.

Threshold fieldSets a threshold value so that a red indicator appears in the timebar at frames where the average residual exceeds this value.

Reconstruct buttonCreates an axis in 3D space for the selected tracker.

To track the 3D camera and analyse the 3D tracking results:

  1. In the manual 3D tracking menu, click Analysis.
  2. In the Analysis menu, click Track Camera.
  3. For each tracker, peruse the residual and average residual values.

    Look at the 3D axes of your track points and determine if their appearance is viable for the 3D track. The coordinates of each track point axis should point in the directions you expect.

  4. If the average residual value for a particular tracker exceeds the threshold, disable Enabled for the tracker. You can repeat this step for more than one tracker.
  5. If you want to reanalyse the manual 3D track, in the schematic, delete all track Axis nodes.

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  6. If necessary, go to the Stabilizer and revise a few 2D trackers.
  7. Go to the Coordinates menu and verify the coordinate system.
  8. Return to the Frames menu, click Initialise Frames.
  9. In the Analysis menu, click Track Camera.