Using Help | Contents | Index Back - Adobe AFTER EFFECTS 5.5 Help Manual

Adobe After Effects Help
Using Help | Contents
Defining tracking settings (PB only)
Use the Options dialog box, available from the Tracker/Stabilizer Controls, to specify the
second layer or the effect, and to define other tracking settings. The controls are as
follows:
Layer menu Specifies the layer you want to attach to the tracked layer.
Effect Point Control menu Specifies an effect to attach to the track point. Note that you
can attach only those effects that have position properties.
Frames per Second Specifies a frame rate for tracking. In general, the tracking frame rate
should match the frame rate of the footage, which should match the composition's frame
rate.
If you are attaching a motion graphic to the tracked area, be sure to match the frame
rates of the two layers.
Track Fields Tracks the motion in both video fields of interlaced video. The Track Fields
option doubles the frame rate to ensure that both video fields are tracked.
Track in Reverse Tracks backward in time. For example, if you are tracking an object that
comes in from off-screen, you can define your tracking regions at the end of the clip and
then track backward in time.
Use Specifies the type of comparison method to use for tracking an object in subsequent
frames. RGB bases tracking on all three color channels. Luminance compares the contrast
in brightness values in the tracking region. Saturation looks at how much color is present
in the tracking region.
Process Before Match Blurs or sharpens an image to enhance the search capabilities.
Select Blur to specify the number of pixels that the Tracker/Stabilizer blurs before
processing a match. Blurring temporarily reduces noise in the footage to help produce
better tracks.
Note that blurring occurs only for the purpose of tracking. The footage is restored to its
original clarity after tracking. Usually a value of 2 to 3 pixels can help produce better tracks,
especially on grainy or noisy footage. Enhance exaggerates the edges of an image to
make them easier to track.
Track Adaptiveness Controls how much of the original frame and the following frame
are used for matching. A value of 100% means that the Tracker/Stabilizer updates the
feature information from one frame to the next, based on the location of the feature
region. A value of 0% means that the Tracker/Stabilizer uses feature information from only
the original image when matching each subsequent frame. Use larger values if your
feature changes shape, color, or brightness during the tracked frames. Use smaller values if
the feature doesn't vary across the tracked frames or if subpixel drifting is a problem.
Extrapolate Motion if Accuracy is Below _% Specifies a tolerance level that determines
when the Tracker/Stabilizer extrapolates the motion of hidden objects. If the accuracy
percentage falls below the specified tolerance, the Tracker/Stabilizer extrapolates the
position of the feature region while it is obscured by another object. For example, if you
track a dog that walks behind a person, the Tracker/Stabilizer can estimate the position of
the dog in those frames where it is obscured.
Using Help | Contents
Using Property and Tracking Controls (PB only)
| Index
| Index
Back 308
Back 308