Feature tracking algorithms are then used to correlate all of the features over time. The objects of interest can further be isolated and quantified. In the following figure and the animation, the objects with positive vorticity are colored with reddish color, and those with negative vorticity are colored with bluish color. Color is also used to encode the history of object evolution.
Objects have the same color throughout their lifetime.
When objects merge, the object with larger area establishes the color. The object of interest is marked with a cross at its centroid.