The individual cells in the flame front are tracked
by segmenting individual frames of videotape and matching
corresponding cells in successive frames. We can determine
position, size and shape of the individual cells.
In the 12/3 hopping mode, the twelve cells in the outer ring remain stationary, while the inner three cells hop - appearing to play musical chairs among four slots. The motion seems periodic to the eye, but the cells actually move irregularly in space and time.
Cells
Tracked
The individual cells in the flame front are tracked
by segmenting individual frames of videotape and matching
corresponding cells in successive frames. We can determine
position, size and shape of the individual cells.
Time-Lapse of Centers
In this view
the cell center positions are represented by color-coded dots.
The dots are accumulated over each frame of videotape to form
a time-lapse representation of the motion. The time-lapse of
the cell centers shows the spatial irregularity of the hops. When
viewed closely the cell centers appear to move along the sides of a
rectangle for short periods of time. The orientation of the rectangle
changes as the hopping progresses.
Animation
This animation of the hopping motion emphasizes the
rectangles along which the hopping cells appear to move. The positions
during which two cells are stationary are represented by color-coded
disks connected by a line. The lines fade gradually as the animation
proceeds to improve visual persistence.