High Dynamic Range Imaging (eBook)

Front cover 1
The Morgan Kaufmann Series in Computer Graphics 4
Copyright page 6
Title page 7
About the Authors 10
Table of contents 11
Foreword 17
Preface 19
Acknowledgements 20
1 Introduction 21
2 Light and Color 39
Radiometry 39
Photometry 44
Colorimetry 48
Color Spaces 53
White Point and Illuminants 56
Color Correction 68
Color Opponent Spaces 70
Color Appearance 77
Display Gamma 89
Brightness Encoding 93
Standard RGB Color Spaces 96
3 HDR Image Encodings 105
LDR Versus HDR Encodings 105
Applications of HDR Images 107
HDR Image Formats 109
The HDR Format 111
The TIFF Float and LogLuv Formats 113
The OpenEXR Format 117
Other Encodings 118
Emerging "Lossy" HDR Formats 119
HDR Encoding Comparison 126
Conclusions 131
4 HDR Image Capture 135
Photography and Light Measurement 135
HDR Image Capture from Multiple Exposures 137
Film Scanning 138
Image Registration and Alignment 142
The Mean Threshold Bitmap Alignment Technique 143
Threshold Noise 148
Overall Algorithm 151
Efficiency Considerations 154
Results 155
Deriving the Camera Response Function 156
Debevec and Malik Technique 157
Mitsunaga and Nayar Technique 160
Choosing Image Samples for Response Recovery 162
Caveats and Calibration 163
Ghost Removal 167
Lens Flare Removal 172
The Point Spread Function 172
Estimating the PSF 175
Removing the PSF 179
Direct Capture of HDR Imagery 179
Viper FilmStream 180
SMaL 181
Pixim 182
SpheronVR 183
Point Grey Research 183
Conclusions 184
5 Display Devices 187
Hardcopy Devices 187
The Reflection Print 188
Transparent Media 190
HDR Still Image Viewer 191
Softcopy Devices 196
Cathode-ray Tubes and Liquid Crystal Displays 196
Sunnybrook Technologies’ HDR Displays 199
Other Display Technologies 202
6 The Human Visual System and HDR Tone Mapping 207
Tone-mapping Problem 207
Human Visual Adaptation 211
The Pupil 213
The Rod and Cone Systems 213
Photo-pigment Depletion and Regeneration 216
Photoreceptor Mechanisms 217
Visual Adaptation Models for HDR Tone Mapping 226
Photoreceptor Adaptation Model for Tone Mapping 227
Threshold Versus Intensity Model for Tone Mapping 230
Background Intensity in Complex Images 231
Image Average As Ib 231
Local Average As Ib 232
Multiscale Adaptation 235
Dynamics of Visual Adaptation 239
Summary 241
7 Spatial Tone Reproduction 243
Preliminaries 244
Calibration 245
Color Images 248
Homomorphic Filtering 251
Gaussian Blur 253
Validation 255
Global Operators 257
Miller Brightness-ratio-preserving Operator 257
Tumblin–Rushmeier Brightness-preserving Operator 262
Ward Contrast-based Scale Factor 266
Ferwerda Model of Visual Adaptation 267
Logarithmic and Exponential Mappings 272
Drago Logarithmic Mapping 275
Reinhard and Devlin Photoreceptor Model 278
Ward Histogram Adjustment 286
Schlick Uniform Rational Quantization 293
Local Operators 297
Chiu Spatially Variant Operator 298
Rahman Retinex 301
Fairchild iCAM 306
Pattanaik Multiscale Observer Model 312
Ashikhmin Spatially Variant Operator 321
Reinhard et al. Photographic Tone Reproduction 325
Pattanaik Adaptive Gain Control 333
Yee Segmentation-based Approach 336
Summary 343
8 Frequency Domain and Gradient Domain Tone Reproduction 345
Frequency Domain Operators 345
Oppenheim Frequency-based Operator 346
Durand Bilateral Filtering 353
Choudhury Trilateral Filtering 360
Gradient Domain Operators 365
Horn Lightness Computation 366
Fattal Gradient Domain Compression 372
Performance 377
Local and Global Operators 379
Gradient and Frequency Domain Operators 380
Discussion 382
9 Image-based Lighting 387
Introduction 387
Basic Image-based Lighting 390
Acquire and Assemble the Light Probe Image 390
Model the Geometry and Reflectance of the Scene 392
Map the Light Probe to an Emissive Surface Surrounding the Scene 393
Render the Scene as Illuminated by the IBL Environment 394
Postprocess the Renderings 396
Capturing Light Probe Images 401
Photographing a Mirrored Sphere 402
Tiled Photographs 407
Fish-eye Lenses 409
Scanning Panoramic Cameras 410
Capturing Environments with Very Bright Sources 412
Omnidirectional Image Mappings 421
Ideal Mirrored Sphere 422
Angular Map 424
Latitude-Longitude 425
Cube Map 427
How a Global Illumination Renderer Computes IBL Images 429
Sampling Other Surface Reflectance Types 434
Sampling Incident Illumination Efficiently 436
Identifying Light Sources 440
Converting a Light Probe into a Constellation of Light Sources 448
Importance Sampling 456
Simulating Shadows and Scene-Object Interreflection 459
Differential Rendering 464
Rendering into a Nondiffuse Local Scene 465
Useful IBL Approximations 466
Environment Mapping 467
Ambient Occlusion 472
Image-based Lighting for Real Objects and People 474
A Technique for Lighting Real Subjects 474
Relighting from Compressed Image Data Sets 476
Conclusions 481
Acknowledgements 481
Appendix A List of symbols 483
References 487
Index 509
About the DVD-ROM 517