About the Authors xv Series Preface xvii Preface xix List of Abbreviations xxiii About the CompanionWebsite xxvii 1 Introduction 1 1.1 Image Content and Image Quality 2 1.1.1 Color 3 1.1.2 Shape 8 1.1.3 Texture 10 1.1.4 Depth 11 1.1.5 Luminance Range 12 1.1.6 Motion 15 1.2 Benchmarking 18 1.3 Book Content 22 Summary of this Chapter 24 References 25 2 Defining Image Quality 27 2.1 What is Image Quality? 27 2.2 Image Quality Attributes 29 2.3 Subjective and Objective Image Quality Assessment 31 Summary of this Chapter 32 References 33 3 Image Quality Attributes 35 3.1 Global Attributes 35 3.1.1 Exposure, Tonal Reproduction,

and Flare 35 3.1.2 Color 39 3.1.3 Geometrical Artifacts 40 3.1.3.1 Perspective Distortion 40 3.1.3.2 Optical Distortion 42 3.1.3.3 Other Geometrical Artifacts 42 3.1.4 Nonuniformities 43 3.1.4.1 Luminance Shading 45 3.1.4.2 Color Shading 45 3.2 Local Attributes 45 3.2.1 Sharpness and Resolution 45 3.2.2 Noise 49 3.2.3 Texture Rendition 50 3.2.4 Color Fringing 50 3.2.5 Image Defects 51 3.2.6 Artifacts 51 3.2.6.1 Aliasing and Demosaicing Artifacts 52 3.2.6.2 Still Image Compression Artifacts 53 3.2.6.3 Flicker 53 3.2.6.4 HDR Processing Artifacts 55 3.2.6.5 Lens Ghosting 55 3.3 Video Quality Attributes 56 3.3.1 Frame Rate 56 3.3.2 Exposure and White Balance Responsiveness and Consistency 58 3.3.3 Focus Adaption 58 3.3.4 Audio-Visual Synchronization 58 3.3.5 Video Compression Artifacts 59 3.3.6 Temporal

Noise 60 3.3.7 Fixed Pattern Noise 60 3.3.8 Mosquito Noise 60 Summary of this Chapter 60 References 61 4 The Camera 63 4.1 The Pinhole Camera 63 4.2 Lens 64 4.2.1 Aberrations 64 4.2.1.1 Third-Order Aberrations 65 4.2.1.2 Chromatic Aberrations 66 4.2.2 Optical Parameters 67 4.2.3 Relative Illumination 69 4.2.4 Depth of Field 70 4.2.5 Diffraction 71 4.2.6 Stray Light 73 4.2.7 Image Quality Attributes Related to the Lens 74 4.3 Image Sensor 75 4.3.1 CCD Image Sensors 75 4.3.2 CMOS Image Sensors 77 4.3.3 Color Imaging 81 4.3.4 Image Sensor Performance 82 4.3.5 CCD versus CMOS 89 4.3.6 Image Quality Attributes Related to the Image Sensor 90 4.4 Image Signal Processor 91 4.4.1 Image Processing 91 4.4.2 Image Compression 98 4.4.2.1 Chroma Subsampling 98 4.4.2.2 Transform Coding 98

4.4.2.3 Coefficient Quantization 99 4.4.2.4 Coefficient Compression 100 4.4.3 Control Algorithms 101 4.4.4 Image Quality Attributes Related to the ISP 101 4.5 Illumination 102 4.5.1 LED Flash 103 4.5.2 Xenon Flash 103 4.6 Video Processing 103 4.6.1 Video Stabilization 103 4.6.1.1 Global Motion Models 104 4.6.1.2 Global Motion Estimation 105 4.6.1.3 Global Motion Compensation 106 4.6.2 Video Compression 107 4.6.2.1 Computation of Residuals 107 4.6.2.2 Video Compression Standards and Codecs 109 4.6.2.3 Some Significant Video Compression Standards 110 4.6.2.4 A Note On Video Stream Structure 111 4.7 System Considerations 111 Summary of this Chapter 112 References 113 5 Subjective Image Quality Assessment-Theory and Practice 117 5.1 Psychophysics 118 5.2 Measurement Scales 120 5.3 PsychophysicalMethodologies 122

5.3.1 Rank Order 123 5.3.2 Category Scaling 123 5.3.3 Acceptability Scaling 124 5.3.4 Anchored Scaling 125 5.3.5 Forced-Choice Comparison 125 5.3.6 Magnitude Estimation 125 5.3.7 Methodology Comparison 126 5.4 Cross-Modal Psychophysics 126 5.4.1 Example Research 127 5.4.2 Image Quality-Related Demonstration 128 5.5 Thurstonian Scaling 129 5.6 Quality Ruler 131 5.6.1 Ruler Generation 134 5.6.2 Quality Ruler Insights 135 5.6.2.1 Lab Cross-Comparisons 135 5.6.2.2 SQS2 JND Validation 136 5.6.2.3 Quality Ruler Standard Deviation Trends 139 5.6.2.4 Observer Impact 141 5.6.3 Perspective from Academia 142 5.6.4 Practical Example 144 5.6.5 Quality Ruler Applications to Image Quality Benchmarking 147 5.7 Subjective Video Quality 148 5.7.1 Terminology 149 5.7.2 Observer Selection 149 5.7.3 Viewing Setup 150 5.7.4 Video

Display and Playback 151 5.7.5 Clip Selection 152 5.7.6 Presentation Protocols 154 5.7.7 Assessment Methods 156 5.7.8 Interpreting Results 158 5.7.9 ITU Recommendations 159 5.7.9.1 The Double-Stimulus Impairment Scale Method 160 5.7.9.2 The Double-Stimulus Continuous Quality Scale Method 160 5.7.9.3 The Simultaneous Double-Stimulus for Continuous Evaluation Method 160 5.7.9.4 The Absolute Category Rating Method 161 5.7.9.5 The Single Stimulus Continuous Quality Evaluation Method 161 5.7.9.6 The Subjective Assessment of Multimedia Video Quality Method 161 5.7.9.7 ITU Methodology Comparison 162 5.7.10 Other Sources 162 Summary of this Chapter 162 References 163 6 Objective Image Quality Assessment-Theory and Practice 167 6.1 Exposure and Tone 168 6.1.1 Exposure Index and ISO Sensitivity 168 6.1.2 Optoelectronic Conversion Function 169 6.1.3

Practical Considerations 170 6.2 Dynamic Range 170 6.3 Color 171 6.3.1 Light Sources 171 6.3.2 Scene 174 6.3.3 Observer 176 6.3.4 Basic Color Metrics 178 6.3.5 RGB Color Spaces 180 6.3.6 Practical Considerations 181 6.4 Shading 181 6.4.1 Practical Considerations 182 6.5 Geometric Distortion 182 6.5.1 Practical Considerations 184 6.6 Stray Light 184 6.6.1 Practical Considerations 185 6.7 Sharpness and Resolution 185 6.7.1 The Modulation Transfer Function 186 6.7.2 The Contrast Transfer Function 191 6.7.3 Geometry in Optical Systems and the MTF 193 6.7.4 Sampling and Aliasing 194 6.7.5 System MTF 195 6.7.6 Measuring the MTF 198 6.7.7 Edge SFR 198 6.7.8 Sine Modulated Siemens Star SFR 201 6.7.9 Comparing Edge SFR and Sine Modulated Siemens SFR 203 6.7.10 Practical Considerations 204 6.8 Texture Blur 204

6.8.1 Chart Construction 206 6.8.2 Practical Considerations 206 6.8.3 AlternativeMethods 207 6.9 Noise 207 6.9.1 Noise and Color 207 6.9.2 Spatial Frequency Dependence 209 6.9.3 Signal to Noise Measurements in Nonlinear Systems and Noise Component Analysis 211 6.9.4 Practical Considerations 212 6.10 Color Fringing 213 6.11 Image Defects 214 6.12 Video Quality Metrics 214 6.12.1 Frame Rate and Frame Rate Consistency 215 6.12.2 Frame Exposure Time and Consistency 215 6.12.3 Auto White Balance Consistency 216 6.12.4 Autofocusing Time and Stability 216 6.12.5 Video Stabilization Performance 217 6.12.6 Audio-Video Synchronization 218 6.13 Related Internat

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