Repositioning the Search Region

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Repositioning the Search Region

Normally the search region is based on the recent tracker history using the current shot prediction mode and the search region parameters, as described in the previous section.

You can also manually key the search region (separate from the tracker itself).

The manually-positioned search region shows SynthEyes where to begin to look for the pattern (though it can finish somewhat outside). You can relocate and/or tighten up the search region by adjusting its corner handles.

Here are some situations where manually-keyed search regions are useful:

 when a shot contains an object already moving at significant speed at the main frame (you provide search guidance while the predictor gets up to speed);

 when there are repeating textures such as brick or windows, and the tracker has jumped to the wrong repetition;

 there is a small short-term occluding object knocking the tracker off course (some quick search guidance can be easier than masking);

 when there is a big bump in an otherwise-smooth shot.

Keying the search region is a very powerful and useful technique ; you should key the search region, rather than the tracker, whenever possible.

If you re-position the tracker's corner keys manually, you will typically introduce glitches in the final tracker, camera, and object path. By keying the search region, you still allow SynthEyes to find the best match, avoiding unnecessary glitches.

To set a key on the search region, you can

 drag the search rectangle,

 drag an individual corner,

 shift-drag a corner to scale the search region,

 rotate it with the virtual rotation handles (just outside the corners.

The tracker will update when you stop dragging. After you have keyed the search rectangle, its corner handles will be red on that frame, and a key will be shown in the main time bar.

Large search regions will greatly increase compute time; rotating the default search rectangle can inadvertently create very large search regions.

You can remove the manually-set keys on the search rectangle on a particular frame by shift-right-clicking the search rectangle. If the control key is down, all search rectangle keys will be deleted.

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