IPAN Tracker IP97

The algorithm summarized here is described in full detail in section 4.
Original reference: [4].
Additional assumptions: A speed limit and a cost limit are given. The maximum duration of an occlusion is 2 frames. Events in $F_{1}$, $F_{2}$, $F_{3}$ are allowed but may lead to wrong initialization of the trajectories involved.
Initialization: $F_{1}$ and $F_{2}$ are treated separately as 3 frames are needed to form a cost function. Otherwise, the same linking strategy is used. (See below.)
Cost function: As in SJ87. (See (1).)
Linking strategy: Non-iterative, competitive linking algorithm in forward direction. Based on repetitive hypothesis testing procedure which switches between 3 consecutive frames. The already established links are used when available. The points that remain unlinked either close or open a trajectory.
Occlusion handling: A post-processing step exploits the directional continuity of broken trajectories. Occluded points are generated so as to minimize the cost function. A trajectory remains broken if the speed exceeds the limit or if the occlusion extends to 3 or more frames.