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Prediction Modes and Hand-Held Shots
SynthEyes predicts where the feature will appear in each new frame, in order to minimize the required area that must be searched. That not only saves time, but more importantly minimizes the chances that a nearby similar-looking but incorrect feature is selected instead.
SynthEyes has different prediction modes for different types of shots. By default, in the Steady camera mode, it assumes that the shot is smooth, from a steadi-cam, dolly, or crane, and uses the previous history over a number of frames to predict its next position.
If your shot and the individual trackers are very rough, especially as you are tracking the first few trackers, you may find that the trackers aren’t too predictable, and you can set the mode to Hand-Held: Sticky, in which case SynthEyes simply looks for the feature at its previous location (requiring a comparatively large search region).
Once you've already tracked several trackers on a hand-held shot, select Hand- Held: Use others on the Track menu. In this mode, SynthEyes uses other, already- tracked, trackers to predict the location of new ones. You can greatly reduce the search size and will need to set new keys only occasionally as the pattern changes.
Using the predict mode, you’ll sometimes find that a tracker is suddenly way out of position, that it isn’t looking in the right place. If you check your other trackers, you’ll find that one of your previously-tracked trackers is off course on either this or the previous frame. You should unlock that tracker, repair it, relock it, and you’ll see that the tracker you were originally working on is now in the correct place (you may need to back up a frame and then track onto this frame again).
For some special situations, the Re-track at existing mode uses the previously- tracked location, and looks again nearby (perhaps after a change in some tracker settings). The search size can be kept small, and the tracker will not make any large jumps to an incorrect location, if the track is basically correct to begin with. SynthEyes uses this mode during fine-tuning. Note: on any frames that were not previously tracked, Hand-Held: Sticky mode will be used.
Once a shot is solved, and a tracker has been assigned a 3-D location (either by the solve or because it is a zero-weighted tracker), an additional option becomes possible: looking for the tracker at the location predicted from its solved 3-D location.
This feature is controlled by the Search from solved option on the Track menu, and is on by default. It is useful for adding or extending trackers, or for stereo shots, but not for offset trackers. For more information see the section on Post-Solve Tracking.
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