Framework
The hierarchy of perception and control levels that forms the framework
for the driving program is presented in the figure below. While the picture
is definitely not exhaustive, all the relevant components are represented.
At the top a scheduler selects from a set of task-specific behaviors
the one that should be activated at any given moment. The behaviors use
visual routines to gather the information they need and act accordingly.
Finally, the visual routines are composed from an alphabet of basic
operations (similar to the proposal in [Ullman84]).
The implemented modules are described below, starting from the highest
level in the hierarchy.
