Apple Shake 4 - Manual (Page 736)

736 Chapter 25 Image Tracking, Stabilization, and SmoothCam
To smooth a track curve:
1 Right-click the track you want to smooth, then choose Smooth Tracks from the shortcut
menu.
The Smooth Track window appears.
2 Enter a value (or use the slider) in the smoothValue field.
The default is 5, which means that 5 track points centered on the currently evaluated
point are used to compute the current point’s new, smoothed value. This is a standard
Gaussian (bell-curve type) filter. In other words, if you leave it at 5, when the value of
frame 12 is computed, frames 10, 11, 12, 13, and 14 are considered. If set to 3, it uses
frames 11, 12, and 13.
The larger the smoothValue, the more points are considered (and thus more
calculations done) for every point in the curve. Even values for smoothValue use the
next largest odd number of frames, but the end ones do not contribute as much.
As an example, the following is a noisy track curve (before smoothing):