5.1.1

Chapter 22 Motion tracking 994
Note: In a Stabilize behavior, only tracks from other Stabilize behaviors can be chosen from the
tracking behaviors pop-up menu.
Tracking behavior controls
Analyze Motion controls
The Analyze Motion behavior is designed for use with footage (a movie or image sequence). This
behavior can be thought of as a traditional correlation tracker—you position an onscreen tracker
on a reference pattern on a clip. The movement of the clip at the specied reference point is
analyzed, and the analyzed data is saved in the behavior. The recorded data can then be applied
to other objects in the project.
The Analyze Motion behavior does not transform the input image. It is used to generate tracks
that can be referenced by the Match Move, Stabilize, Track Parameter, and Track Shape behaviors.
For information on using the Analyze Motion behavior, see Analyze Motion workow on
page 960.
Analyze Motion cannot reference other tracking behaviors. It can be applied only to footage
objects (a QuickTime movie or image sequence).
Parameters in the Inspector
•
Movement: The Movement parameter group contains the Analyze and Reverse controls:
•
Analyze: This button, when clicked, begins the motion-tracking analysis. When you click
Analyze, a status window appears and displays the tracking progress. To stop the analysis,
click the Stop button in the status window or press Esc.
The start of the track is based on the current playhead position, rather than the start of the
behavior in the Timeline.
•
Reverse: This checkbox, when selected, reverses the analysis direction, going from the
playhead position to the rst frame of the clip (or the rst frame of the tracking behavior).
Note: You must move the playhead to the frame where you want the reverse analysis
to begin.
•
Tracker: This button lets you add trackers to the Analyze Motion behavior. By default, one
tracker is available. New trackers are added at the center of the Canvas.
•
Tracker Preview: This preview area provides a magnied view of the tracking reference area
for the selected tracker. The preview updates as you adjust the position of the tracker in the
Canvas. You can drag in the preview area to adjust the position of the tracker. When dragging
in the preview area, the image moves around the red crosshair that represent the tracker,
while the tracker moves in the Canvas. You can also Option-drag left or right to decrease or
increase pattern size. (You can also adjust the Track Size slider to achieve the same result.)
•
Oset Track: This checkbox lets you select a new reference point when the original reference
point becomes temporarily hidden or goes o the screen. Motion uses the new tracking point
to continue the same tracking path as the original reference point. For more information on
oset tracking, see Track obscured or o-frame points on page 988.
•
Auto-Zoom: This pop-up menu lets you choose a magnication level when positioning the
tracker in the Canvas. You can zoom in on the Canvas when searching for an ideal tracking
reference pattern. There are four choices: None, 2x, 4x, and 8x.
•
Auto-Zoom Mode: This pop-up menu lets you set the display of the auto-zoomed tracker in the
Canvas. There are three choices:
67% resize factor