Based on the Lagrangian framework for fluid dynamics, a streakline
representation of flow is presented to solve computer vision
problems involving crowd and traffic flow. Streaklines are traced
in a fluid flow by injecting color material, such as smoke or dye,
which is transported with the flow and used for visualization. In
the context of computer vision, streaklines may be used in a
similar way to transport information about a scene, and they are
obtained by repeatedly initializing a fixed grid of particles at
each frame, then moving both current and past particles using
optical flow. Streaklines are the locus of points that connect
particles which originated from the same initial position. In this
paper, a streakline technique is developed to compute several
important aspects of a scene, such as flow and potential functions
using the Helmholtz decomposition theorem. This leads to a
representation of the flow that more accurately recognizes spatial
and temporal changes...
Ramin Mehran, Brian E. Moore, Mubarak Shah