CISMM

Data Set and Source

Download data set

This data comes from David Hill at Richard Superfine’s laboratory at the University of North Carolina at Chapel Hill. It is data from 2.8-micron beads diffusing in a 2% mucus solution. This is a good test case for tracking because the beads go in and out of focus, and move past stationary objects on the cover slip. The beads do not take large steps between frames, so the follow_jumps control is not required.

Recommended Analysis Procedure

Put two symmetric (default) trackers on the two beads, setting their radius to 22 pixels. Set the small_area checkbox. Turn on optimize. The tracking window should look something like this:

Press play_video. The trackers should follow the two beads as they move in the image. This particular video was chosen because it is a good test of the capabilities of the spot tracker program. As the beads go in and out of focus, they change from bright-centered to dark-centered and also become clearer and blurrier. The symmetric tracker was developed to handle exactly this case, where the objects being tracked are circularly symmetric but otherwise vary dramatically during tracking. Also, the beads pass under non-moving small blemishes in the image caused by specks on the imager or on the lenses; the large symmetric kernels do not respond to such features unless they are correlated with the circular symmetry of the particles being tracked.