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Using Help | Contents
To delete a tracked area:
1 Reposition the In and Out points to include only the area of the track you want to
delete.
2 Press the Delete key. After Effects deletes only the tracked area between the In and Out
buttons.
Correcting a drifting feature region (PB only)
There are two main methods for realigning a feature region if it drifts off track during
tracking. If most of the footage tracked accurately, you may need only to move the feature
region in selected frames. If drifting occurs early in the footage, you can modify the
tracking settings and then track again from the beginning.
Under certain conditions, you can correct drifting by simply enlarging the search region
(for example, if the search region is too small to contain erratic movement of the feature
region from one frame to the next). Note that increasing the size of the search region
increases the tracking time.
To correct drifting by moving the feature region:
1 Drag the current-time indicator to the last well-tracked frame.
2 Do one of the following:
To correct a single frame, drag the feature region or track point to new locations. Alt-
•
drag (Windows) or Option-drag (Mac OS) the feature region to move it without moving
the track point. Use the Details section of the window to monitor the feature region
position. The tracker automatically updates the previous tracking data to this new
feature region/track point position.
To correct several contiguous frames, drag the feature region or track point to new
•
locations as described above and click Analyze. Watch the tracking to make sure it is
accurate. If not, press any key to stop tracking, adjust the feature region, and begin
again.
3 To preview tracking, press the spacebar.
4 When you are satisfied with the track, click Apply to copy keyframes to the selected
layer.
To correct drifting by modifying tracking settings:
1 Drag the current-time indicator to the last well-tracked frame.
2 Click Options and change the following settings:
If colors change in the feature region, increase the Track Adaptiveness value.
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Select Process Before Match, select Blur, and then type a value of 2 to 3 pixels. Select
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Enhance if the edges of the feature are fuzzy. Deselect the Blur option if you want to use
Subpixel Matching.
Choose a value from 1/2 to 1/16 for Subpixel Matching. A smaller fraction increases the
•
accuracy of the tracker but also increases tracking time.
If the area to be tracked has high contrast, change the Use option to Luminance. Try
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Saturation if the area has a high concentration of color.
If the area is partially obscured during tracking, set a tolerance value for Extrapolate
•
Motion if Accuracy Is Below_%. Determine the proper value by creating a trial track and
Using Help | Contents
Using Property and Tracking Controls (PB only)
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