Boundary trace slope feature detection system

摘要

A character feature detection system is provided for reliably reading alphanumeric characters. An information field is scanned by sensor array and the sensor responses are digitized to form a binary character image. The image is traced from boundary point to boundary point. A transition from one boundary point to another is defined by one of eight equally divergent vectors which are indicative of the local slope of a boundary between connected points. The sequence of vectors in their xy locations recorded in the boundary slopes are indicated by averaging vectors representative of the cell to cell transition. Character features are detected from the sequence of boundary slopes to form a feature set. The feature decision logic analyzes the primary features to form a set of secondary features based upon the occurrence and order of the features. The set of secondary features are then analyzed in a sequential logic decision tree to identify the character.