An expert vision system for autonomous land vehicle road following

A production-system model of problem solving is applied to the design of a vision system by which an autonomous land vehicle (ALV) navigates roads. The ALV vision task consists of hypothesizing objects in a scene model and verifying these hypotheses using the vehicles sensors. Object hypothesis generation is based on the local navigation task, and a priori road map, and the contents of the scene model. Verification of an object hypothesis involves directing the sensors toward the expected location of the object, collecting evidence in support of the object, and reasoning about the evidence. Constructing the scene model consists of building a semantic network of object frames exhibiting component, spatial, and inheritance relationships. The control structure is provided by a set of communicating production systems implementing a structured blackboard; each production system contains the rules for defining the attributes of a particular class of object frame