Annotating videos with high-quality point tracks is a very challenging task. We use an optical flow based point interpolation to aid the human annotators in this task. On the left below are annotations obtained without this tracker, and on the right with the tracker. The tracker results in more spatially consistent tracks, and also speeds up the annotation process by over 40%, aiding and simplifying the annotation effort substantially.
Without flow tracker assist | With flow tracker assist |
Note the high-frequency jitter for the points on the swan's back and neck that occurs without assitance from optical flow. | |
Without flow tracker assist | With flow tracker assist |
Camera shake is particularly problematic, but optical flow compensates very well. It's almost unnoticeable when the flow interpolation is used, but without it, the points jump visibly three-quarters of the way through the video. | |
Without flow tracker assist | With flow tracker assist |
The flow tracker remains consistent even with fast motions, greatly improving the precision of the points on the horse's saddle. | |
Without flow tracker assist | With flow tracker assist |
Again the flow tracker is useful in compensating for camera motion and zoom. |