Table of Contents

The Line Drawing Interpretation Problem: Motivation.- Manual Input vs Document Scanning.- Raster-Based vs Symbolic Representations Engineering Drawings and Maps.- Line Drawing Interpretation, Image Understanding and Pattern Recognition.- Current Line Drawing Interpretation Systems.- The Line Drawing Interpretation Literature.- Components of a Line Drawing Interpretation System: Design Criteria for Drawing Interpretation Systems.- Five Stages of Line Drawing Interpretation.- Intermediate and Target Representations.- Systems Architectures and the Role of A Priori Knowledge.- Document Image Acquisition: Scanning Devices.- Image Coding.- Image File Formats.- Binarisation: A Taxonomy of Thresholding Techniques.- Document Image Statistics.- Binarising Line Drawings.- Binary Image Processing and the Raster to Vector Transformation: Raster to Vector Conversion.- Some Definitions.- The Distance Transform.- Mathematical Morphology.- Reducing Noise in Binary Images.- Reducing Noise in Binary Images of Line Drawings.- Analysis of Connected Components: Nomenclature.- Contouring.- Skeletonisation.- Grey-Level Skeletonisation.- Vectorisation: Approaches to Vectorisation.- Global Vectorisation Methods.- Local Vectorisation Methods.- The Hough Transform.- Direct Vectorisation.- A Vector Database.- Removing Noise from the Vector Model.- Alternative Raster-to-Vector Technologies.- Interpreting Images of Maps: Introduction.- Systems Overview.- Map Interpretation Principles.- A Classification of Map Entities.- Interactive Map Interpretation.- Output Formats.- Quality Issues.- Recognising Cartographic Objects: Recognising Isolines.- Recognising Roads.- Recognising Texture and Area Objects.- Recognising Symbols.- Recovering Engineering Drawing Entities from Vector Data: Design Principles and System Architecture.- Vectorisation and Entity Recognition Processes.- Extracting Arcs and Straight Lines.- Recognising Crosshatched Areas.- Recognising Dimensions.- Detecting Blocks.- Knowledge-Directed Interpretation of Engineering Drawings: An Image Understanding Approach.- Drawing Entities as Schemata.- Image Analysis Facilities.- The ANON Architecture.- Control Issues.- Entity Extraction: Chained Lines.- Top-Down and Bottom-Up Control.- Performance.- Scene Formation.- ANON in Context.- Discussion.- Output and Conclusions: Draughting Digitised Information.- Other Applications of Line Drawing Interpretation.- Topics for Further Development.- References.- Index.