I am motion tracking a video in which the camera turns away from one scene and then shortly returns to it. However, the segments that went off-screen lose their track and do not continue tracking once the camera returns. I am wondering if there is a manual way to tell a segment where and when to continue looking for it's tracking target. Is this possible to do?
When an object disappears momentarily form the scene (either it goes out of frame and comes back later, or is occluded by other objects) you can track up to the point where it becomes untrackable or it disappears from the frame.
When it re-appears track it with new tracker.
Then select both trackers (using Shift select)
and Join them using Join Track (or press CtrlJ)
That way blender will know that is dealing with the same element and not a new one.
Doing this will allow you to have a more accurate camera/object solve or better motion stabilization, depending on what your goals are for tracking.