Adding tracking points

Getting Started > Tutorials > Lesson 2: Using supervised tracking >

Adding more tracking points to your scene improves the overall quality of the tracking.

Open the file for the lesson

To ensure this lesson works as described, open the scene file named Shot_tracked.mmf. This file is in the Tutorials directory that you copied from the MatchMover installation directory to a local directory: Tutorials\Supervised_Shot\Shot_tracked.mmf.

Supervised tracking

Eight tracks have been added to the image sequence. In this section of the lesson, you will add more tracking points starting with Track 9.

To make the tracking process quicker, you can use MatchMover's keyboard shortcuts to create the track and run the forward tracking.

To create a new track

Using the image below as a reference, place the mouse pointer in the location shown in the image below. Use the Magnifier window to help find the correct location for the tracking point.
Create the tracking point by pressing Shift+right-click.
The tracking begins then stop around frame 15. Track 09 appears in the Workspace and is also added to the track points in the Project window.
To run forward tracking press F3.
A window appears in the Workspace indicates that the tracking quality is too low for MatchMover to continue the trajectory.
Click OK.
The reason the tracking quality is so low is that the actor’s body hides the area you want track in the sequence.
In the time line, double the last frame of the Track 9 trajectory.

The Parameters window now displays the parameters for the tracked point under the Track 09 tab.

Since the tracked point’s trajectory cannot continue to be tracked, you can change the status of last frame by setting it to an end keyframe. This means that MatchMover will not track forward past this frame.
Select 2D Tracking > Set Key > End.
The End status of the keyframe is indicated in the Track 9 Parameters window in the Status field.
With Track 09 selected, advance the sequence one frame at a time by pressing Ctrl+right arrow key.
As you advance, the tracked point and its trajectory is hidden between frames 16 and 28, then re-appears at frame 29. Since the track is likely to disappear again, this time behind another obstacle, you can track the point frame-by-frame using the Step-tracking mode.
To use Step-tracking mode, press Alt+right arrow to continue tracking forward from frame 29.
At frame 31, a window appears indicating that the tracking quality is too low to continue tracking.

Tip Use the Magnifier window to get a better view of the obstacles that are hiding the Track 09 trajectory path.
At frame 31, change the status of the keyframe to End by selecting 2D Tracking > Set Key > End.
Go to frame 44 and press F3 to run forward tracking.
Track 09 is now complete and set in the scene.

To check the quality of the track

Ensure that Track 9 is selected in the Workspace.
Click the padlock icon at the bottom right of the Magnifier window.
This makes the Magnifier window the only active view.
Select View > Skip Untracked or click the icon.
Play the image sequence in PingPong mode by clicking followed by .
Notice that MatchMover only plays the sections of Track 09 that have been tracked. The frames that could not be tracked because of obstacles in the scene are not played.
Click the lock icon to make the Workspace window active again.
Select View > Skip Untracked so that all frames play when the sequence is played back.