Apple Shake 4 - Manual (Page 727)

Chapter 25 Image Tracking, Stabilization, and SmoothCam 727
update if below reference tolerance This updates the reference sample
from the previous frame if the
correlation is below the
referenceTolerance. This basically says,
“If I can’t get a good match, then
resample.” This is excellent for gradual
perspective and scale shifts in the
tracking area.
failureTolerance If the correlation of a track falls below this value, it initiates the failureBehavior.
failureBehavior What occurs when the correlation drops below the failureTolerance:
stop The tracker stops if the correlation is
less than the failureTolerance. You can
also press Esc to manually stop
tracking.
predict location and create key If a failure is detected, then the
tracker predicts the location of the
keyframe based on a vector of the last
two keyframes, and continues
tracking in the new area.
predict location and don’t create key Same as above, but it merely predicts
the new search area and does not
create new keyframes until a high
correlation is obtained. This is
excellent for tracked objects that pass
behind foreground objects.
don’t predict location In this case, the tracker merely sits in
the same spot looking for new
samples. New keyframes are not
created.
use existing key to predict location This allows you to manually create
keyframes along your track path. You
then return to the start frame and
start tracking. The search pattern
starts looking where the preexisting
motion path is.
limitProcessing Creates a Domain of Definition (DOD) around the bounding boxes of all active
trackers. Only that portion of the image is loaded from disk when tracking, so
the track is faster. This has no effect on the final output image.
preProcess Toggles on the preprocessing for the tracking area. This applies a slight blur to
reduce fluctuations due to grain. To control the blur amount, open the
preProcess subtree.
blurAmount The amount of blur applied when preprocessing.
trackNName The name of the track. To change the name, click in the text field and enter the
new name.
trackNX/Y The actual track point in X and Y. Use this to link a parameter to a track point.
Parameter Description