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Using Help | Contents
K. Tracking accuracy Indicates how accurately each feature region is tracking at the
current time.
L. Options button Opens the Options dialog box, in which you further refine tracking.
For details, see "Defining tracking settings (PB only)" on page 308.
M. Reset button Deletes tracking information.
Defining tracking regions (PB only)
Before tracking motion, define three tracking regions in the motion footage layer: a search
region, a feature region, and a track point. Resize each region by dragging a handle.
Make both regions as small as possible so that the Tracker/Stabilizer can more
accurately and quickly track the selected region. Increasing the size of either region
increases the time required for tracking.
A. Search region B. Feature region C. Track point
Search region Resize the box to define the area outside the feature region that the
Tracker/Stabilizer uses to locate the tracked object or region in the next frame. Large
feature movements between frames require a larger search region to accurately find and
match the feature from one frame to the next.The box must be large enough to contain
the largest possible movement of the feature region from one frame to the next. Although
increasing the search region increases tracking time, it's better for the search region to be
too large than too small.
Feature region Resize the box to precisely define the element you want to track.
Track point Move the cross hair to specify the point of attachment between the tracked
area and the second layer. The Tracker/Stabilizer generates keyframes for the specified
track point and copies them to the position property of the second layer; when you play
back the layers, the second layer is attached to the track point of the first. If you are stabi-
lizing a layer, the Tracker/Stabilizer copies the tracking data to the stabilized layer's anchor
point. If you are attaching an effect instead of a second layer, the Tracker/Stabilizer copies
the keyframes to the specified effect point. You can place this effect point anywhere in the
image. The cross hair is not visible when the tracker is in stabilize mode, because the track
point is always the center of the feature region.
To move the search region, feature region, and track point all at once, drag between
the handles of the feature region. To move the feature region without moving the
track point, Alt-drag (Windows) or Option-drag (Mac OS) the feature region.
Using Help | Contents
Using Property and Tracking Controls (PB only)
| Index
A
B
C
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