2009

used both during a manual tracking review (see Batch Track Rollout on page
3838) or during actual tracking to correct errors using the Resample On Error
control in the Motion Trackers setup rollout on page 3830.
Interface
Match Error A sum-of-differences-squared measure in RGB space of the best
match in the current frame to the feature target from the previous keyframe.
The error shown is a percentage of the maximum possible image difference.
Good matches are usually below 0.05 percent.
Variance Delta The difference in RGB color variance between the feature
target image and the current best match. This measures whether the target
and match have similar color ranges and can compensate for mistakes made
by the sum-of-differences measure.
Jump Delta The tracker computes a moving average for the preceding five
frames and measures the difference between that average and the jump in the
current frame. If this difference exceeds the current Jump delta threshold, a
potential error is flagged. If the threshold is set to five, any jump in the current
frame that’s five pixels more than the average jump in the last five frames is
flagged. This picks up sudden accelerations rather than just large jumps.
You can adjust the thresholds as needed and enable or disabled individual
measures in the detector using the check boxes to the left of each measure.
Camera Tracker: Batch Track Rollout
Utilities panel > Utilities rollout > More button > Utilities dialog > Camera
Tracker > Batch Track rollout
The Camera Tracker utility's Batch Track rollout performs feature hands-off
tracking once the trackers have been set up. You can set up a set of trackers,
start a batch tracking of them all, and then use the other tools in this panel
to check for and review detected tracking errors. This panel also checks for
tracking completion.
3838 | Chapter 15 Animation