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Adjusting the Search Region Parameters
Here we see a 3-D planar tracker as it tracks through a shot.
The outer rectangle is the search region, which is only displayed on non-key frames. In addition to the presence of the search rectangle, the blue color of the corner handles of the tracker and the search rectangle indicates that neither is keyed on the frame; they are red when keyed.
This is an automatically generated search rectangle; it is determined based on the shot's prediction mode and the search region parameters at the bottom of the Planar Control Panel.
The search parameters are initially based on the prediction mode; it is up to you to adjust them based on what you see over the course of tracking. If the shot proves to be too bouncy or move too rapidly, so that tracking is lost or shifts to an incorrect configuration, you should increase the appropriate search size parameter.
The search region controls for planar trackers includes rotation and scaling settings as well as the horizontal and vertical settings of conventional trackers. A large rotation setting may be needed for hand-held shots that suddenly dutch left and right or any shot that pinwheels around the camera axis. A larger scale setting may be needed to track objects that are rapidly approaching or receding from the camera.
The values do not have to be set to some exact values; they are approximate.
The search only starts in the search rectangle; it can finish outside it if the situation warrants. You can watch the search rectangle versus the tracker rectangle as the shot tracks; if the tracker rectangle is frequently close to or outside the search rectangle, you should increase the search parameters accordingly. Or, decrease them if the shot is very stable.
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