Technical Drawings and Forms -- 3D Reconstruction of Paper Based Assembly Drawings: State of the Art and Approach -- Interpretation of Low-Level CAD Data for Knowledge Extraction in Early Design Stages -- Knowledge-Based Partial Matching: An Efficient Form Classification Method -- Robust Frame Extraction and Removal for Processing Form Documents -- Validation, User Interfaces -- Issues in Ground-Truthing Graphic Documents -- Sketch-Based User Interface for Inputting Graphic Objects on Small Screen Devices -- Experimental Evaluation of a Trainable Scribble Recognizer for Calligraphic Interfaces -- User Interfaces for On-Line Diagram Recognition -- Symbol Segmentation and Recognition -- Symbol Recognition: Current Advances and Perspectives -- An Error-Correction Graph Grammar to Recognize Texture Symbols -- Perceptual Organization -- Perceptual Organization as a Foundation for Graphics Recognition -- Exploiting Perceptual Grouping for Map Analysis, Understanding and Generalization: The Case of Road and River Networks -- Extraction of Contextual Information Existing among Component Elements of Origami Books -- Map Recognition -- Text/Graphics Separation in Maps -- Semantic Analysis and Recognition of Raster-Scanned Color Cartographic Images -- Structure Based Interpretation of Unstructured Vector Maps -- Generating Logic Descriptions for the Automated Interpretation of Topographic Maps -- Graphics Recognition Technology -- Scan-to-XML: Using Software Component Algebra for Intelligent Document Generation -- Interpreting Sloppy Stick Figures by Graph Rectification and Constraint-Based Matching -- Using a Generic Document Recognition Method for Mathematical Formulae Recognition -- Interpreting Line Drawing Images: A Knowledge Level Perspective -- Vectorization and Early Processing -- Smoothing and Compression of Lines Obtained by Raster-to-Vector Conversion -- A Scale and Rotation Parameters Estimator Application to Technical Document Interpretation -- Improving the Accuracy of Skeleton-Based Vectorization -- Structural Rectification of Non-planar Document Images: Application to Graphics Recognition -- An Effective Vector Extraction Method on Architectural Imaging Using Drawing Characteristics -- Thresholding Images of Line Drawings with Hysteresis -- Math Notation, Charts, Music Notation -- A Recognition Method of Matrices by Using Variable Block Pattern Elements Generating Rectangular Area -- Music Manuscript Tracing -- Arc Segmentation Contest -- Extended Summary of the Arc Segmentation Contest -- TIF2VEC, An Algorithm for Arc Segmentation in Engineering Drawings -- RANVEC and the Arc Segmentation Contest -- Summary of Panel Discussions at GREC’2001.

This book presents refereed and revised papers presented at GREC 2001, the 4th IAPR International Workshop on Graphics Recognition, which took place in Kingston, Ontario, Canada in September 2001. Graphics recognition is a branch of document image analysis that focuses on the recognition of two-dimensional notations such as engineering drawings, maps, mathematical notation, music notation, tables, and chemical structure diagrams. Due to the growing demand for both o?-line and on-line document recognition systems, the ?eld of graphics recognition has an excitingand promisingfuture. The GREC workshops provide an opportunity for researchers at all levels of experience to share insights into graphics recognition methods. The workshops enjoy strongparticipation from researchers in both industry and academia. They are sponsored by IAPR TC-10, the Technical Committee on Graphics Recog- tion within the International Association for Pattern Recognition. Edited v- umes from the previous three workshops in this series are available as Lecture Notes in Computer Science, Vols. 1072, 1389, and 1941. After the GREC 2001 workshop, authors were invited to submit enhanced versions of their papers for review. Every paper was evaluated by three reviewers. We are grateful to both authors and reviewers for their careful work during this review process. Many of the papers that appear in this volume were thoroughly revised and improved, in response to reviewers’ suggestions.