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The Theory of the Moiré Phenomenon
by
Isaac Amidror



Table of Contents of Vol. II:


Preface xiii

1. Introduction 1

           1.1 The moiré effect between aperiodic structures 1
           1.2 A brief historical background and main applications 4
           1.3 The scope of the present book 5
           1.4 Overview of the following chapters 7
           1.5 About the exercises and the moiré demonstration samples 9

2. Background and basic notions 11

           2.1 Introduction 11
           2.2 Periodic, repetitive and aperiodic layers 15
           2.3 Superposition of aperiodic layers 19
                      2.3.1 Glass patterns and correlation 19
                      2.3.2 Stable vs. singular moiré-free superpositions 24
                      2.3.3 Macrostructures and microstructures in the superposition 26
           2.4 The element distribution in the original layers and its influence 28
           2.5 Multilayer superpositions 30
           Problems 32

3. Glass patterns and fixed loci 47

           3.1 Introduction 47
           3.2 The fixed point theorem 48
           3.3 Behaviour of Glass patterns and periodic moirés under affine mappings 51
                      3.3.1 Behaviour under layer rotations 51
                      3.3.2 Behaviour under layer scalings 53
                      3.3.3 Behaviour under layer shifts 54
                      3.3.4 Behaviour under a general affine transformation 59
           3.4 Behaviour of Glass patterns under general layer transformations 63
                      3.4.1 Examples with non-linear layer mappings 65
           3.5 Mappings in both layers; mutual fixed loci 72
           3.6 Synthesis of fixed loci in the superposition 83
           3.7 Almost fixed points 87
           Problems 96

4. Microstructures: dot trajectories and their morphology 105

           4.1 Introduction 105
           4.2 Morphology of the microstructures; dot trajectories 106
           4.3 Dot trajectories as solution curves of a system of differential equations 107
           4.4 Dot trajectories as a vector field 109
                      4.4.1 The curve equations of the dot trajectories 114
           4.5 The dot trajectories when both layers undergo transformations 124
           4.6 Synthesis of dot trajectories 134
           4.7 Dot trajectories in periodic and in repetitive cases 137
           4.8 The microstructures under different superposition rules 139
           4.9 The visual interpretation of microstructures 140
           Problems 148

5. Moiré phenomena between periodic or aperiodic screens 157

           5.1 Introduction 157
           5.2 Brief review: moiré patterns, Glass patterns and dot trajectories 158
           5.3 A few detailed examples to illustrate the formal results 161
           5.4 Invariance properties of moiré patterns, Glass patterns and dot trajectories 175
           Problems 181

6. Glass patterns in the superposition of aperiodic line gratings 187

           6.1 Introduction 187
           6.2 Glass patterns in the superposition of straight line gratings 188
                      6.2.1 Superposition of 1D vs. 2D aperiodic layers 189
                      6.2.2 Superposition of periodic vs. aperiodic line gratings 192
           6.3 Mathematical derivations: generalization of the indicial equations method 193
           6.4 Examples of Glass patterns in the superposition of curved line gratings 196
           6.5 The effect of adding constraints to the original layers 208
           6.6 A first step towards the intensity profiles of Glass and moiré patterns 214
           Problems 221

7. Quantitative analysis and synthesis of Glass patterns 225

           7.1 Introduction 225
           7.2 Brief review of the Fourier approach in the periodic case 226
                      7.2.1 Spectra of periodic and aperiodic layers 228
                      7.2.2 Moiré effects in the superposition of periodic gratings 230
                      7.2.3 Moiré effects in the superposition of periodic dot screens 233
                      7.2.4 Shape of the intensity profile of the moiré pattern 236
                      7.2.5 Orientation and size of the moiré cells 238
           7.3 Intensity profile of Glass patterns in the superposition of aperiodic gratings 238
                      7.3.1 Superposition of correlated gratings 240
                      7.3.2 Superposition of uncorrelated gratings 246
           7.4 Intensity profile of Glass patterns in the superposition of aperiofic screens 248
                      7.4.1 Superposition of correlated screens 249
                      7.4.2 Shape of the intensity profile of the Glass pattern 252
                      7.4.3 Orientation and size of the Glass pattern 253
                      7.4.4 Cases with several fixed points or with continuous fixed lines 254
                      7.4.5 Superposition of uncorrelated screens 258
                      7.4.6 Discussion 258
           7.5 Higher order moirés 259
           7.6 Intermediate, partly periodic cases 260
           7.7 Intermediate, partly correlated cases 262
           7.8 Glass patterns and cross correlation 264
           Problems 270


Appendices

A. Fixed point theorems for first- and second-order polynomial mappings 281

           A.1 Introduction 281
           A.2 The fixed point theorem for linear or affine mappings 281
           A.3 The fixed point theorem for second-order polynomial mappings 284
           A.4 Mutual fixed points between two mappings; application to the moiré theory 288

B. The various interpretations of a 2D transformation 289

           B.1 Introduction 289
           B.2 Interpretation as two surfaces over the plane or as two sets of level lines 289
           B.3 Interpretation as a mapping from the plane into itself 290
           B.4 Interpretation as a domain transformation r(g(x,y)) 294
           B.5 Interpretation as a coordinate change 295
           B.6 Interpretation as a 2D vector field 298
           B.7 Relationship between the different representations of g(x,y) 301
           B.8 Remark on the local reflection of a 2D transformation 306

C. The Jacobian of a 2D transformation and its significance 309

           C.1 Introduction 309
           C.2 Geometric interpretation of the Jacobian 309
           C.3 Properties of the transformation g(x,y) that can be deduced from its Jacobian 311
           C.4 The local orientation properties of a transformation g(x,y) 319
           C.5 Other properties of g(x,y) that can be deduced from its Jacobian matrix 322

D. Direct and inverse spatial transformations 327

           D.1 Introduction 327
           D.2 Background and basic notions 327
           D.3 A deeper look into the domain and range planes of the mapping (u,v) = g(x,y) 332
           D.4 2D transformations and their inverse 336
                      D.4.1 The image of the standard Cartesian grid under the
                                         transformations g and g-1
337
                      D.4.2 The image of a general curve under the transformations g and g-1 340
           D.5 The active and passive interpretations of a transformation 343
           D.6 Domain and range transformations of a function 347
                      D.6.1 The 1D case 349
                      D.6.2 The 2D case 351
                      D.6.3 The effect of transformation g on objects and on their
                                         characteristic functions
355
           D.7 The relative point of view: object deformations vs. coordinate deformations 356
           D.8 Examples 357
           D.9 Other possible sources of confusion 386
                      D.9.1 Forward and backward mapping algorithms in digital imaging 386
                      D.9.2 Pre-multiplication and post-multiplication based notations 389
           D.10 Implications to the moiré theory: issues related to the figures 390
           D.11 Fixed points of a superposition in terms of direct or inverse transformations 399
                      D.11.1 Fixed points when only one layer is transformed 399
                      D.11.2 Fixed points when both layers undergo transformations 401
           D.12 Useful approximations 405

E. Convolution and cross correlation 411

           E.1 Introduction 411
           E.2 Convolution 411
           E.3 Cross correlation 413
           E.4 Extension to more general cases 415
           E.5 The Fourier transform of convolution and cross correlation 416
           E.6 Methods for quantifying the correlation; similarity measures 418

F. The Fourier treatment of random images and of their superpositions 421

           F.1 Introduction 421
           F.2 Stochastic processes and their power spectra 421
           F.3 Possible stochastic modelizations of random screens and gratings 425
                      F.3.1 Point processes 425
                      F.3.2 Shot noise 426
                      F.3.3 Random fields 429
           F.4 Stochastic modelization of layer superpositions 430
           F.5 Evaluation of the stochastic vs. deterministic approaches for our application 430

G. Integral transforms 433

           G.1 Introduction 433
           G.2 Fourier decomposition of periodic and aperiodic structures 433
           G.3 Generalized Fourier decomposition of geometrically transformed structures 434
           G.4 Integral transforms and their kernels 435
           G.5 The use of generalized Fourier transforms in the moiré theory 439

H. Miscellaneous issues and derivations 443

           H.1 Classification of the dot trajectories 443
                      H.1.1 Classification of the dot trajectories in the linear case 444
                      H.1.2 Classification of the dot trajectories in the non-linear case 447
           H.2 The connection between the vector fields h1(x,y) and h2(x,y) in Sec. 4.5 451
           H.3 Hybrid (1,-1)-moiré effects whose moiré bands have 2D intensity profiles 452

I. Glossary of the main terms 457

           I.1 About the glossary 457
           I.2 Terms in the image domain 457
           I.3 Terms in the spectral domain 461
           I.4 Terms related to moiré 463
           I.5 Terms related to light and colour 466
           I.6 Miscellaneous terms 467

List of notations and symbols 473

List of abbreviations 475

References 477

Index 485



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Last modified: 2008/10/23