About the Authors p. xv
Series Preface p. xvii
Preface p. xix
List of Abbreviations p. xxiii
About the Companion Website p. xxvii
Introduction p. 1
Image Content and Image Quality p. 2
Color p. 3 Shape p. 8 Texture p. 10 Depth p. 11 Luminance Range p. 12 Motion p. 15 Benchmarking p. 18 Book Content p. 22
Summary of this Chapter p. 24
References p. 25
Defining image Quality p. 27
What is Image Quality? p. 27
Image Quality Attributes p. 29
Subjective and Objective Image Quality Assessment p. 31
Summary of this Chapter p. 32
References p. 33
Image Quality Attributes p. 35
Global Attributes p. 35
Exposure, Tonal Reproduction, and Flare p. 35
Color p. 39
Geometrical Artifacts p. 40
Perspective Distortion p. 40
Optical Distortion p. 42
Other Geometrical Artifacts p. 42
Nonuniformities p. 43
Luminance Shading p. 45
Color Shading p. 45
Local Attributes p. 45
Sharpness and Resolution p. 45
Noise p. 49
Texture Rendition p. 50
Color Fringing p. 50
Image Defects p. 51
Aliasing and Demosaicing Artifacts p. 52
Still Image Compression Artifacts p. 53
Flicker p. 53
HDR Processing Artifacts p. 55
Lens Ghosting p. 55
Video Quality Attributes p. 56
Frame Rate p. 56
Exposure and White Balance Responsiveness and Consistency p. 58
Focus Adaption p. 58
Audio-Visual Synchronization p. 58
Video Compression Artifacts p. 59
Temporal Noise p. 60
Fixed Pattern Noise p. 60
Mosquito Noise p. 60
Summary of this Chapter p. 60
References p. 61
The Camera p. 63
The Pinhole Camera p. 63
Lens p. 64 Aberrations p. 64 Third-Order Aberrations p. 65 Chromatic Aberrations p. 66 Optical Parameters p. 67 Relative Illumination p. 69 Depth of Field p. 70 Diffraction p. 71 Stray Light p. 73
Image Quality Attributes Related to the Lens p. 74
Image Sensor p. 75
CCD Image Sensors p. 75
CMOS Image Sensors p. 77
Color Imaging p. 81
Image Sensor Performance p. 82
CCD versus CMOS p. 89
Image Quality Attributes Related to the Image Sensor p. 90
Image Signal Processor p. 91
Image Processing p. 91
Image Compression p. 98
Chroma Subsampling p. 98
Transform Coding p. 98
Coefficient Compression p. 100
Control Algorithms p. 101
Image Quality Attributes Related to the ISP p. 101
Illumination p. 102
LED Flash p. 103
Xenon Flash p. 103
Video Processing p. 103
Video Stabilization p. 103
Global Motion Models p. 104
Global Motion Estimation p. 105
Global Motion Compensation p. 106
Video Compression p. 107
Computation of Residuals p. 107
Video Compression Standards and Codecs p. 109
Some Significant Video Compression Standards p. 110
A Note On Video Stream Structure p. 111
System Considerations p. 111
Summary of this Chapter p. 112
References p. 113
Subjective Image Quality Assessment-Theory and Practice p. 117
Psychophysics p. 118 Measurement Scales p. 120 Psychophysical Methodologies p. 122 Rank Order p. 123 Category Scaling p. 123 Acceptability Scaling p. 124 Anchored Scaling p. 125 Forced-Choice Comparison p. 125 Magnitude Estimation p. 125 Methodology Comparison p. 126 Cross-Modal Psychophysics p. 126 Example Research p. 127
Image Quality-Related Demonstration p. 128
Thurstonian Scaling p. 129
Quality Ruler p. 131
Ruler Generation p. 134
Quality Ruler Insights p. 135
Lab Cross-Comparisons p. 135
SQS<sub>2</sub>, JND Validation p. 136
Quality Ruler Standard Deviation Trends p. 139
Perspective from Academia p. 142
Practical Example p. 144
Quality Ruler Applications to Image Quality Benchmarking p. 147
Subjective Video Quality p. 148
Terminology p. 149
Observer Selection p. 149
Viewing Setup p. 150
Video Display and Playback p. 151
Clip Selection p. 152
Presentation Protocols p. 154
Assessment Methods p. 156
Interpreting Results p. 158
ITU Recommendations p. 159
The Double-Stimulus Impairment Scale Method p. 160
The Double-Stimulus Continuous Quality Scale Method p. 160 The Simultaneous Double-Stimulus for Continuous Evaluation Method p. 160
The Absolute Category Rating Method p. 161
The Single Stimulus Continuous Quality Evaluation Method p. 161 The Subjective Assessment of Multimedia Video Quality Method p. 161
ITU Methodology Comparison p. 162
Other Sources p. 162
Summary of this Chapter p. 162
References p. 163
Objective Image Quality Assessment-Theory and Practice p. 167
Exposure and Tone p. 168
Exposure Index and ISO Sensitivity p. 168
Opto-Electronic Conversion Function p. 169
Practical Considerations p. 170 Dynamic Range p. 170 Color p. 171 Light Sources p. 171 Scene p. 174 Observer p. 176
Basic Color Metrics p. 178
RGB Color Spaces p. 180 Practical Considerations p. 181 Shading p. 181 Practical Considerations p. 182 Geometric Distortion p. 182 Practical Considerations p. 184 Stray Light p. 184
Practical Considerations p. 185
Sharpness and Resolution p. 185
The Modulation Transfer Function p. 186
The Contrast Transfer Function p. 191
Geometry in Optical Systems and the MTF p. 193
Sampling and Aliasing p. 194
System MTF p. 195
Measuring the MTF p. 198
Edge SFR p. 198
Sine Modulated Siemens Star SFR p. 201
Comparing Edge SFR and Sine Modulated Siemens SFR p. 203
Practical Considerations p. 204 Texture Blur p. 204 Chart Construction p. 206 Practical Considerations p. 206 Alternative Methods p. 207 Noise p. 207
Noise and Color p. 207
Spatial Frequency Dependence p. 209
Signal to Noise Measurements in Nonlinear Systems and Noise Component Analysis p. 211
Practical Considerations p. 212
Color Fringing p. 213
Image Defects p. 214
Video Quality Metrics p. 214
Frame Rate and Frame Rate Consistency p. 215
Frame Exposure Time and Consistency p. 215
Auto White Balance Consistency p. 216
Autofocusing Time and Stability p. 216
Video Stabilization Performance p. 217
Audio-Video Synchronization p. 218
Related International Standards p. 218
Summary of this Chapter p. 221
References p. 221
Perceptually Correlated Image Quality Metrics p. 227
Aspects of Human Vision p. 227
Physiological Processes p. 227
HVS Modeling p. 232
Viewing Conditions p. 232
Spatial Image Quality Metrics p. 234
Sharpness p. 235
Mapping Acutance to JND Values p. 237
Other Perceptual Sharpness Metrics p. 239
Texture Blur p. 239
Visual Noise p. 240
Color p. 244
Chromatic Adaptation Transformations p. 244
Color Appearance Models p. 245
Color and Spatial Content-Image Appearance Models p. 247
Image Quality Benchmarking and Color p. 249
Other Metrics p. 251
Combination of Metrics p. 252
Full-Reference Digital Video Quality Metrics p. 252
PSNR p. 253
Structural Similarity (SSIM) p. 256
VQM p. 260
VDP p. 262
Further Considerations p. 263
Discussion p. 265
Summary of this Chapter p. 267
References p. 267
Measurement Protocols-Building Up a Lab p. 273
Still Objective Measurements p. 273
Lab Needs p. 274
Lab Space p. 274
Lighting p. 275
Light Booths p. 278
Transmissive Light Sources p. 279
Additional Lighting Options p. 280
Light Measurement Devices p. 281
Charts p. 282
Printing Technologies for Reflective Charts p. 282
Technologies for Transmissive Charts p. 286
Inhouse Printing p. 286
Chart Alignment and Framing p. 287
Camera Settings p. 289
Supplemental Equipment p. 289
Real World Objects p. 290
Video Objective Measurements p. 293
Visual Timer p. 293
Motion p. 294
Lab Needs p. 297
Stimuli p. 298
Stimuli Generation p. 298
Stimuli Presentation p. 301
Observer Needs p. 302
Observer Selection and Screening p. 302
Experimental Design and Duration p. 303
Video Subjective Measurements p. 304
Summary of this Chapter p. 305
References p. 305
The Camera Benchmarking Process p. 309
Objective Metrics for Benchmarking p. 309
Subjective Methods for Benchmarking p. 311
Photospace p. 312
Use Cases p. 313
Observer Impact p. 314
Methods of Combining Metrics p. 315
Weighted Combinations p. 316 Minkowski Summation p. 316 Benchmarking Systems p. 317 GSM Arena p. 317 FNAC p. 318 VCX p. 318
Skype Video Capture Specification p. 319
VIQET p. 320
DxOMark p. 321
IEEE P185S p. 323
Example Benchmark Results p. 324
VIQET p. 324
IEEE CPIQ p. 325
CPIQ Objective Metrics p. 327
CPIQ Quality Loss Predictions from Objective Metrics p. 337
DxOMark Mobile p. 338
Real-World Images p. 339
High-End DSLR Objective Metrics p. 339
Benchmarking Validation p. 345
Summary of this Chapter p. 348
References p. 349
Summary and Conclusions p. 353
References p. 357