LKTracker -- User's Guide

This is a pre-release version (a nightly built prototype) of LKTracker (LK stands for Lucas Kanade, they are the inventors of the method employed), a motion tracking solution for the FastCut video editor. You will need a registered FastCut version to run it. Notice that the final name of the program isn't definite. Other conceivable names are 'Back on Track', 'Motion Tracker' or 'mtrack'. You can send in proposals.

Here is how to use the tool:

After application launch, you are prompted to specify the source movie file's location. LKTracker can open movie files with .mov, .mp4, and .m4v file extensions. Your next step is to determine the movie segment you wish to work with. Move the playhead slider and hit the 'Set In Pt and 'Set Out Pt' buttons respectively. By holding down the shift key while pressing these buttons you can jump to the in and out point. Now, click the mouse in the movie track view and drag and drop the appearing green box to a location where you want the track path to begin. Implicitly, the playhead moves to the in point position. The center of the green box should be positioned at a point which is clearly defined, high-contrast and always in the frame the entire time (between in and out point). If you click the 'Analyse' button now, the program goes through and watches the point you defined as it moves. It creates a motion track in a few seconds consisting of a series of tracking points. Beneath the playhead slider is a gray bar that indicates the analysed area.

If you observe a wrong tracking behavior, i.e. the calculated track pursues a wrong path, then move the playhead up to that point in time where everything is all right and press the 'Set Mid Pt' button (the new mid point must be between in and out point). After that move the center of the green box in the movie track view back to a correct location. This way you can help the software to 'get back on track'. If there are analysed track points after the mid point, by setting the mid point those points are removed. Incidentally, whenever you hit the 'Set In Pt' button, you also set the mid point to that fixed point in time. If you hit 'Analyse', the mid point will be moved towards the out point.

The aim is to move an object along the tracking path which you generate with LKTracker. After the calculation, you can export the tracking path by choosing 'Export .mtr File …' from the 'File' menu. Then click on a clip in your FastCut movie project and re-import the tracking data by choosing 'Animate Using .mtr File …'. The keyframes which potentially exist before are overwritten.

If you want to learn more about the Lucas Kanade method, go to <http://www.comp.nus.edu.sg/~cs4243/lecture/motion.pdf>.

If you want to watch a screen movie tutorial about the motion tracker built in the Apple Motion software, go to <https://www.youtube.com/watch?v=Y74fczQc0Oc&t=204s>.

You can obtain more products from the developer who has written this piece of software online, please visit <http://www.timesforfun.de/>.