This correspondence presents a system for detecting dimension sets in engineering drawings that are drawn to ANSI drafting standards. A new rule-based text/graphics separation algorithm and a model-based procedure for detecting arrowheads in any orientation have been developed. Arrowhead tracking and search methods are used to extract leaders, tails, and witness lines from segmented images containing only graphics. Text blocks and feature control frames extracted from the segmented images are than associated with their corresponding leaders to obtain complete dimension sets. Experimental results are presented.>

The authors present efficient methodologies for interpreting manhole drawings of a telephone company for information extraction. They have developed a skew correction algorithm for deskewing scanned images, a new rule-based text/graphics separation algorithm for separating annotations in the drawings, and a graphics interpretation system which includes model-based arrow head detection, splice detection, and recognition of interconnections of cables and stubs. The final result from the interpretation system is a table which includes an ordered list of all cables and their interconnections which are contained in a manhole. Experimental results are used throughout to describe the algorithms.>

A system for detecting dimension sets in engineering drawings that are drawn to ANSI drafting standards is presented. A new rule-based text/graphics separation algorithm and a model-based procedure for detecting arrowheads in any orientation have been developed. Arrowhead tracking and search methods are used to extract leaders, tails, and witness lines from segmented images containing only graphics. Text blocks and feature control frames extracted from the segmented images are then associated with their corresponding leaders to obtain complete dimension sets. Object lines are then separated from centerlines and hatching lines. Experimental results are presented.>