
Chapter 9 Motion Tracking
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Target Update Criteria
menu
Determines how often the motion of the target is estimated.
The choices include:
Always Update. Estimates the motion between two
adjacent frames in time.
No Update. Estimates between the frame at the keyframe
and the current frame. If your target object does not change
through the course of the video, use the No Update or Auto
Update option.
Auto Update. Estimates once with the target from the
previous keyframe. If the estimation fails, the estimation is
re-calculated with an updated target. If the tracker fails
again, the tracker projects the previous estimate or assumes
no motion, depending on the Failure Mode and Failure
Threshold.
Threshold Is only visible in Auto Update Mode and determines the
quality at which the tracker reverts to another update
method. The quality is determined by measuring the
similarity between the target image and the best match in
the search region.
• If the quality using No Update falls below 50 percent,
the tracker tries again using the Update mode.
• If Threshold is set to 100, the filter always uses the No
Update mode.
Failure Mode menu After trying both No Update and Update modes, the quality
is still below the Threshold value, the tracker uses the
parameter settings. The options include:
Continue. Projects the data from the previous frame. This
preserves the object's inertia.
Wait. Assumes no motion, forcing you to set a new
keyframe to continue the analysis. Use for an object that
moves off screen and returns. The tracker waits until the
object returns and detects the object.
Ignore. Does not use the Failure Threshold setting, so the
tracking data is returned regardless of quality.
Parameter Description
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