About the Book

Rendering High Dynamic Range (HDR) scenes on media with limited dynamic range began in the Renaissance whereby painters, then photographers, learned to use low-range spatial techniques to synthesize appearances, rather than to reproduce accurately the light from scenes. The Art and Science of HDR Imaging presents a unique scientific HDR approach derived from artists’ understanding of painting, emphasizing spatial information in electronic imaging.

Human visual appearance and reproduction rendition of the HDR world requires spatial-image processing to overcome the veiling glare limits of optical imaging, in eyes and in cameras. Illustrated in full colour throughout, including examples of fine-art paintings, HDR photography, and multiple exposure scenes; this book uses techniques to study the HDR properties of entire scenes, and measures the range of light of scenes and the range that cameras capture. It describes how electronic image processing has been used to render HDR scenes since 1967, and examines the great variety of HDR algorithms used today. Showing how spatial processes can mimic vision, and render scenes as artists do, the book also:

• Gives the history of HDR from artists' spatial techniques to scientific image processing
• Measures and describes the limits of HDR scenes, HDR camera images, and the range of HDR appearances
• Offers a unique review of the entire family of Retinex image processing algorithms
• Describes the considerable overlap of HDR and Color Constancy: two sides of the same coin
• Explains the advantages of algorithms that replicate human vision in the processing of HDR scenes
• Provides extensive data to test algorithms and models of vision on an accompanying website.
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• Contents:

• Section A HISTORY OF HDR IMAGING 1

  1 HDR Imaging 3

  1.1 Topics 3

  1.2 Introduction 3

  1.3 Replicas and Reproductions 4

  1.4 A Choice of Metaphors for HDR Reproduction 5

  1.5 Reproduction of Scene Dynamic Range 7

  1.6 HDR Disciplines 8

  1.7 Outline of the Text 10

  1.8 Summary 11

  1.9 References 12

  2 HDR Tools and Defi nitions 13

  2.1 Topics 13

  2.2 Introduction 13

  2.3 Pixels 14

  2.4 Dynamic Ranges 14

  2.5 Measuring Light 17

  2.6 Measuring Color Spaces 18

  2.7 Image Reproduction 21

  2.8 Contrast 24

  2.9 Digital Imaging 25

  2.10 Summary 25

  2.11 References 26

  3 HDR in Natural Scenes 27

  3.1 Topics 27

  3.2 Appearance in HDR and Color Constancy 27

  3.3 Summary 30

  3.4 References 31

  4 HDR in Painting 33

  4.1 Topics 33

  4.2 Introduction 33

  4.3 Ancient Painting 33

  4.4 Perspective 35

  4.5 Chiaroscuro 37

  4.6 Gerritt van Honthorst (Gherardo delle Notti) 37

  4.7 Rembrandt van Vijn 40

  4.8 John Constable 40

  4.9 John Martin 40

  4.10 Impressionism 41

  4.11 Photorealism 43

  4.12 Summary 43

  4.13 References 44

  5 HDR in Film Photography 45

  5.1 Topics 45

  5.2 Introduction 45

  5.3 Multiple Exposures in the 1850s 46

  5.4 HP Robinson 47

  5.5 Hurter and Driffi eld-Scientifi c Calibration of AgX Film Sensitivity 48

  5.6 Sheppard and Mees 50

  5.7 19th Century – Professional Amateur Photography 50

  5.8 20th Century – Corporate Photography 50

  5.9 20th Century Control of Dynamic Range 51

  5.10 Other Silver-Halide Stories 56

  5.11 Summary 56

  5.12 References 57

  6 The Ansel Adams Zone System 59

  6.1 Topics 59

  6.2 Introduction 59

  6.3 Compressing the HDR World into the LDR Print 59

  6.4 Visualization 60

  6.5 Scene Capture 61

  6.6 “Performing the Score” 65

  6.7 Moonrise, Hernandez 66

  6.8 Apparent vs. Physical Contrast 66

  6.9 Summary 66

  6.10 References 68

  7 Electronic HDR Image Processing: Analog and Digital 69

  7.1 Topics 69

  7.2 Introduction 69

  7.3 Human Spatial Vision 69

  7.4 Electronic HDR Image Processing 70

  7.5 Summary 74

  7.6 References 75

  8 HDR and the World of Computer Graphics 77

  8.1 Topics 77

  8.2 Introduction 77

  8.3 Early Years: the 60s 78

  8.4 Early Digital Image Synthesis: the 70s 78

  8.5 The Turning Point: the 80s 79

  8.6 Computational Photorealism: from the 90s 80

  8.7 Summary 80

  8.8 References 81

  9 Review of HDR History 83

  9.1 Topics 83

  9.2 Summary of Disciplines 83

  9.3 Review 84

  9.4 Summary 87

  9.5 References 87

  Section B MEASURED DYNAMIC RANGES 89

  10 Actual Dynamic Ranges 91

  10.1 Topics 91

  10.2 Introduction 91

  10.3 Dynamic Range of Light Sensors 92

  10.4 Bits per Pixel 93

  10.5 Dynamic Range of Display Devices 94

  10.6 Interactions of Pixels in Images 95

  10.7 Summary 96

  10.8 References 96

  11 Limits of HDR Scene Capture 99

  11.1 Topics 99

  11.2 Introduction 99

  11.3 HDR Test Targets 99

  11.4 Camera Veiling Glare Limits 101

  11.5 Glare in Film Cameras 107

  11.6 Review 111

  11.7 Summary 111

  11.8 References 112

  12 Limits of HDR in Humans 113

  12.1 Topics 113

  12.2 Introduction 113

  12.3 Visual Appearance of HDR Displays 113

  12.4 von Honthorst’s Painting and the 4scaleBlack HDR Target 116

  12.5 HDR Displays and Black and White Mondrian 116

  12.6 HDR and Tone Scale Maps 117

  12.7 HDR Displays and Contrast 117

  12.8 Summary 117

  12.9 References 118

  13 Why Does HDR Improve Images? 119

  13.1 Topics 119

  13.2 Introduction 119

  13.3 Why are HDR Images Better? 120

  13.4 Are Multiple Exposures Necessary? 120

  13.5 Summary 121

  13.6 References 121

  Section C SEPARATING GLARE AND CONTRAST 123

  14 Two Counteracting Mechanisms: Glare and Contrast 125

  14.1 Topics 125

  14.2 Introduction 125

  14.3 Two Spatial Mechanisms 126

  14.4 Calculated Retinal Image 126

  14.5 Measuring the Range of HDR Appearances 131

  14.6 Calculating the Retinal Image 131

  14.7 Visualizing the Retinal Image 131

  14.8 HDR and Uniform Color Space 132

  14.9 Summary 132

  14.10 References 132

  15 Measuring the Range of HDR Appearances 135

  15.1 Topics 135

  15.2 Introduction 135

  15.3 Design of Appearance Scale Target 136

  15.4 Magnitude Estimation Experiments 138

  15.5 Scene Dependent Tone Scale 141

  15.6 Glare and Contrast 142

  15.7 Summary 143

  15.8 References 143

  16 Calculating the Retinal Image 145

  16.1 Topics 145

  16.2 Introduction 145

  16.3 Converting Scene Luminance to Retinal Contrast 146

  16.4 Calculating Retinal Radiance 146

  16.5 Changes in the Retinal Image from Glare 149

  16.6 Appearance and Retinal Image 149

  16.7 Scene Content and Psychometric Functions 151

  16.8 Summary 151

  16.9 References 152

  17 Visualizing HDR Images 153

  17.1 Topics 153

  17.2 Introduction 153

  17.3 Calculated Retinal Image Contrast 154

  17.4 Retinal Image Contrast 155

  17.5 Summary 159

  17.6 References 159

  18 HDR and Uniform Color Spaces 161

  18.1 Topics 161

  18.2 Introduction 161

  18.3 Uniform Color Spaces – Psychophysics 161

  18.4 Color Vision – Physiology 164

  18.5 Accurate Transformations from CMF to UCS 165

  18.6 Summary 167

  18.7 References 168

  19 Glare: A Major Part of Vision Theory 169

  19.1 Topics 169

  19.2 Introduction 169

  19.3 Glare: Distorts Lightness below Middle Gray, More or Less 169

  19.4 Pixel-based HDR Image Processing 170

  19.5 Summary 171

  19.6 References 171

  Section D SCENE CONTENT CONTROLS APPEARANCE 173

  20 Scene Dependent Appearance of Quanta Catch 175

  20.1 Topics 175

  20.2 Introduction 175

  20.3 Models of Vision – A Choice of Paradigms 175

  20.4 Illumination, Constancy and Surround 176

  20.5 Maximum’s Enclosure and Distance 176

  20.6 Size of Maxima 177

  20.7 Assimilation 177

  20.8 Maxima and Contrast with Maxima 177

  21 Illumination, Constancy and Surround 179

  21.1 Topics 179

  21.2 Introduction 179

  21.3 Hipparchus of Nicea 180

  21.4 Flat-2-D Transparent Displays 182

  21.5 A Simple Two-Step Physical Description 183

  21.6 Complex 3-D Scenes 185

  21.7 Local Maxima 189

  21.8 Review 190

  21.9 Summary 190

  21.10 References 191

  22 Maximum’s Enclosure and Separation 193

  22.1 Topics 193

  22.2 Introduction 193

  22.3 Experimental Design 194

  22.4 Lightness Matches – Light Gray on Black 194

  22.5 Lightness Matches – Dark Gray on Black 195

  22.6 Dark Gray on Black: Varying White’s Position 197

  22.7 Review 198

  22.8 Summary 199

  22.9 References 200

  23 Maxima Size and Distribution 201

  23.1 Topics 201

  23.2 Introduction 201

  23.3 Experimental Procedure 202

  23.4 Controls 202

  23.5 Dispersion of White (“Snow”) 202

  23.6 Sides and Corners 203

  23.7 Lines 204

  23.8 Equivalent Backgrounds 205

  23.9 Equivalent Backgrounds and Models of Vision 207

  23.10 Summary 207

  23.11 References 208

  24 From Contrast to Assimilation 209

  24.1 Topics 209

  24.2 Introduction 209

  24.3 Segmented Surrounds 210

  24.4 Checkerboard Variants 215

  24.5 Summary 216

  24.6 References 216

  25 Maxima and Contrast with Maxima 217

  25.1 Topics 217

  25.2 Merger of Aperture and Object Modes 217

  25.3 Infl uence of the Maxima 218

  25.4 Summary 219

  Section E COLOR HDR 221

  26 HDR, Constancy and Spatial Content 223

  26.1 Topics 223

  26.2 Introduction 223

  26.3 Red and White Projections 224

  26.4 Color Mondrians 225

  26.5 Constancy’s On/Off Switch 225

  26.6 Color of 3-D Mondrians – LDR/HDR Illumination 226

  26.7 Color Constancy is HDR 226

  26.8 References 226

  27 Color Mondrians 227

  27.1 Topics 227

  27.2 Introduction 227

  27.3 Color Mondrians 229

  27.4 The Signature of Color Constancy 237

  27.5 Search for Evidence of Adaptation – Averages 240

  27.6 Transparency in Mondrians 243

  27.7 Color Assimilation 243

  27.8 Summary 244

  27.9 References 245

  28 Constancy’s On/Off Switch 247

  28.1 Topics 247

  28.2 Introduction 247

  28.3 Maximov’s Shoe Boxes 247

  28.4 New Maxima Restores Constancy 250

  28.5 Independent L, M, S Spatial Processing 251

  28.6 Model Predictions 253

  28.7 Center-Surround Target – Results 253

  28.8 Summary 255

  28.9 References 256

  29 HDR and 3-D Mondrians 257

  29.1 Topics 257

  29.2 Color Constancy and Appearance 257

  29.3 Color Constancy Models 258

  29.4 Measuring Changes in Appearance from Changes in Illumination 259

  29.5 Magnitude Estimation Appearance Measurements 262

  29.6 Watercolor Rendition Measurements of Appearance 263

  29.7 Review of 3-D Mondrian Psychophysical Measurements 266

  29.8 Color Constancy Models 268

  29.9 Conclusions 270

  29.10 References 271

  30 Color Constancy is HDR 273

  30.1 Topics 273

  30.2 Introduction 273

  30.3 Rod Receptors and HDR 274

  30.4 Assembling Appearance: Color Constancy, Rod Vision and HDR 279

  30.5 Summary 280

  30.6 References 280

  Section F HDR IMAGE PROCESSING 283

  31 HDR Pixel and Spatial Algorithms 285

  31.1 Topics 285

  31.2 Introduction – HDR Image Processing Algorithms 285

  31.3 One Pixel – Tone Scale Curves 286

  31.4 Some of the Pixels – Local Processing 288

  31.5 All of the Pixels 289

  31.6 All Pixels and Scene Dependent – The Retinex Extended Family 289

  31.7 Retinex Algorithms 290

  31.8 ACE Algorithms 290

  31.9 Analytical, Computational and Variational Algorithms 290

  31.10 Techniques for Analyzing HDR Algorithms 290

  31.11 The HDR Story 291

  31.12 References 291

  32 Retinex Algorithms 293

  32.1 Topics 293

  32.2 Introduction 293

  32.3 How to Calculate Lightness Using Ratio-Products 297

  32.4 A Variety of Processing Networks 301

  32.5 Image Content 302

  32.6 Real Images – 1975 307

  32.7 The Extended Family of Retinex Models 319

  32.8 Algorithm’s Goal 334

  32.9 References 337

  33 ACE Algorithms 341

  33.1 Topics 341

  33.2 Introduction 341

  33.3 ACE Algorithm 341

  33.4 Retinex and ACE 344

  33.5 ACE Characteristics 345

  33.6 RACE 349

  33.7 Other Vision-based Models 350

  33.8 Summary 350

  33.9 References 351

  34 Analytical, Computational and Variational Algorithms 353

  34.1 Topics 353

  34.2 Introduction 353

  34.3 Math in the Framework of the Human Visual System 354

  34.4 Analytical Retinex Formulas 354

  34.5 Computational Retinex in Wavelets 354

  34.6 Retinex and the Variational Techniques 355

  34.7 Summary 356

  34.8 References 357

  35 Evaluation of HDR Algorithms 359

  35.1 Topics 359

  35.2 Introduction 359

  35.3 Quantitative Approaches to Algorithm Evaluation 360

  35.4 Lightness Test Targets 361

  35.5 Ratio Metric 362

  35.6 Quantitative Evaluation of 3-D Mondrians 367

  35.7 Locality Test Targets 369

  35.8 Summary 370

  35.9 Lessons From Quantitative Studies of HDR in Cameras 371

  35.10 References 371

  36 The HDR Story 373

  36.1 Topic 373

  36.2 Straightforward Technology Stories 373

  36.3 The HDR Story is Defi ned by Limits 373

  36.4 HDR Works Well 374

  36.5 References 375