Table 3.

Some implementation strategies in the far-field model.

Major Modules	Implementation Strategy
Top-view mapping	Pre-configured mapping table.
On-line prototype updating	On-line prototype update is triggered only at some key frames.
Appearance Prototype matching	Approximate nearest neighbor search based on the randomized k-d forest or k-means tree.
Spatial context propagation	Apply spatial propagation with 5 × 5 pixel group as a unit.