Style Characterization of Machine Printed Texts Andrew D. Bagdanov
This book is typeset by the author using L A TEX2 ε. The main body of the text is set using the Computer Modern family of fonts. The images and figures are included in the text in encapsulated Postscript format TM Adobe Systems Incorporated. Printing: Febodruk BV, Enschede, The Netherlands. Copyright c 2004 by Andrew D. Bagdanov. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without written permission from the author. ISBN 90-5776-122-X
Style Characterization of Machine Printed Texts ACADEMISCH PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Universiteit van Amsterdam, op gezag van de Rector Magnificus prof. mr. P.F. van der Heijden ten overstaan van een door het College voor Promoties ingestelde commissie, in het openbaar te verdedigen in de Aula der Universiteit op woensdag 26 mei 2004 te 10.00 uur door Andrew David Bagdanov geboren te Burbank, Californië, Verenigde Staten van Amerika
Promotiecommissie: Promotor: Co-promotor: Prof. dr. ir. A.W.M. Smeulders dr. M. Worring Overige leden: Prof. dr. P. van Emde Boas Prof. dr. ir. F.C.A. Groen Prof. dr. G. Nagy Prof. dr. ir. R.J.H. Scha dr. T. Gevers dr. R. Hamberg dr. ir. H.J.A.M. Heijmans Faculteit: Faculteit der Natuurwetenschappen, Wiskunde & Informatica Kruislaan 403 1098 SJ Amsterdam Nederland The work described in this thesis was supported by the ICES-KIS MIA-project and Océ Nederland. Advanced School for Computing and Imaging The work described in this thesis has been carried out within graduate school ASCI, at the Intelligent Sensory Information Systems group of the University of Amsterdam. ASCI dissertation series number 102.
This dissertation is dedicated to my mother and the memory of my father.
Contents 0 Prelude 1 1 Introduction 3 1.1 Elementsofstyle... 3 1.2 Contextandscope... 4 1.2.1 Context... 4 1.2.2 Scope... 7 1.3 Organization of this thesis...... 11 2 Characterizing layout style using first order Gaussian graphs 13 2.1 Definitions and basic concepts.... 14 2.1.1 First order Gaussian graphs... 14 2.1.2 Technicalities... 17 2.1.3 Reflections... 20 2.2 Clustering and classification..... 21 2.2.1 Hierarchical clustering of FOGGs... 21 2.2.2 Classification using first order Gaussian graphs... 23 2.3 Experiments... 25 2.3.1 Test data... 25 2.3.2 Classifiers... 26 2.3.3 Experimental results...... 27 2.3.4 Computational efficiency.... 28 2.3.5 Analysis... 29 2.4 Discussion... 31 3 Multi-scale visual style characterization with rectangular granulometries 35 3.1 Documentgenre... 37 3.2 Granulometries... 39 3.3 Document representation... 41 3.3.1 Rectangular size distributions... 42 3.3.2 Efficiency... 43 3.3.3 Feature space reduction and interpretation... 44 3.4 Experimentalresults... 46 3.4.1 Genre classification... 47 3.4.2 Document image retrieval... 47 i
ii CONTENTS 3.5 Discussion... 49 4 Probing textual style with local vertical granulometries 51 4.1 Another look at granulometries.... 52 4.1.1 The key observation...... 52 4.1.2 Introducing localization.... 54 4.2 An efficient word spotter... 56 4.3 AGenerative model... 59 4.3.1 Glyph distributions...... 59 4.3.2 Agenerative word model... 61 4.4 Experiments and illustration..... 62 4.4.1 Typeface classification..... 63 4.4.2 Word spotting... 65 4.5 Discussion... 69 5Autocorrelation-driven restoration of scanned color halftones 71 5.1 Halftone process color... 72 5.1.1 Halftone color reproduction... 72 5.1.2 Scanned color halftones... 73 5.2 Diffusion of scanned color halftones... 76 5.2.1 Linear diffusion filtering... 77 5.2.2 Nonlinear diffusion filtering... 77 5.3 Measuring local autocorrelation... 79 5.4 Experiments... 82 5.5 Discussion... 85 6 A functional approach to software design in image processing research environments 89 6.1 Introduction... 89 6.2 Acritique of pure reason... 90 6.2.1 Analysis... 92 6.3 Design considerations... 94 6.3.1 Goals... 94 6.3.2 Choice of language... 94 6.3.3 Previous work... 96 6.4 Architecture... 97 6.5 Primitive types and operations.... 97 6.5.1 Types and typing... 98 6.5.2 Primitive image operations...102 6.6 Backend substitution...107 6.7 Casestudies...112 6.7.1 Linear scalespace...113 6.7.2 Complete lattice morphology...117 6.7.3 An algebraic expression compiler...122 6.8 Discussion...128
CONTENTS iii 7 Summary and concluding remarks 131 7.1 Summary...131 7.2 Concludingremarks...133 Bibliography 135 Samenvatting 143 Acknowledgements 145