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Shahlaei, Davoud: Single-image inverse lighting of faces with a virtual light stage. 2017
Inhalt
Abstract
Zusammenfassung
Acknowledgements
Contents
List of Tables
List of Figures
Chapter 1. Introduction
1.1 Motivation and Objectives
1.2 Input and Output of the Proposed Inverse Lighting
1.2.1 Input Image
1.2.2 Approaching the Problem and Overview of the Algorithm
1.3 Contributions
1.4 Publications
Chapter 2. Background and Related Work
2.1 Previous Work
2.1.1 Data-Driven Approaches
2.1.2 Single-Image Approaches
2.1.3 Lighting Design
2.2 The Appearance of Human Faces
2.3 Face Model Extraction with 3DMM from a 2D Image
2.3.1 The 3D Morphable Model (3DMM) of Faces
2.3.2 3DMM Fitting Algorithm and Joint Lighting Estimation
2.3.3 Model-Based Texture Extraction from 2D Image
2.4 Illumination Cone
2.4.1 Lighting Models
2.4.2 Light Sources
2.4.3 Light Stage
2.4.4 Formalizing the Superposition Principle
2.4.5 Estimation of RGB Parameters of Light Sources
2.5 Image Formation
2.5.1 Rendering
2.5.2 Phong Model
2.5.3 Torrance-Sparrow and Dipol Functions
2.5.4 Soft Cast Shadow Mapping
2.5.5 Color Correction
2.6 Cast Shadow Detection and Segmentation
2.7 Image Compression
2.7.1 Downsampling Filters
2.7.2 Compressive Sensing Matrix
2.7.3 Superpixel Segmentation
2.7.4 Texture Patches
Chapter 3. Inverse Lighting and Relighting
3.1 The Inverse Lighting Framework
3.1.1 The Use Case Diagrams for the Proposed Inverse Lighting
3.1.2 An Activity Diagram for the Inverse Lighting Algorithm
3.2 To Span a Synthetic Illumination Cone
3.2.1 Virtual Light Stage (VLS)
3.2.2 Adopting a Measurement-Based Reflectance
3.2.3 Color Correction
3.2.4 3DMM Masks
3.3 Cast Shadow Detection and Segmentation
3.4 Image Compression
3.4.1 Masked Gaussian Downscaling
3.4.2 Geometric Superpixels
3.5 Inverse Lighting Algorithm with Superpixels
3.6 Relighting
3.6.1 Intrinsic Texture Decomposition
3.6.2 Lighting Design
3.7 An Effort to Improve the Estimated Shape after Inverse Lighting
Chapter 4. Estimation by Optimization
4.1 Linear Model
4.2 Cost Function from the Generative Model
4.2.1 Least Squares
4.3 Maximum A-Posteriori (MAP)
4.4 Joint Maximum A-Posteriori (JMAP) for Hyperparameter Optimization
4.4.1 Expected Values of the Priors
4.5 Optimization with Newton-Raphson
4.5.1 Enforcing Nonnegativity and Light-Weight Sparsity
4.5.2 The Hyperparameter Optimization Mechanism
4.5.3 Handling Occlusions and Areas of Misalignment
4.5.4 The Challenge of Cast Shadows
4.6 Implementation Tricks and Magic Numbers
4.7 Alternative Methods
4.7.1 Nonlinear Model ~x = e~
4.7.2 Richardson-Lucy (RL)
4.7.3 Full Hessian Inverse
Chapter 5. Evaluation and Results
5.1 Mean Illumination SIMilarity (MISIM)
5.2 Results
5.2.1 Results of MAP
5.2.2 Ambiguity of the Estimated Lighting
5.2.3 The JMAP Results
5.2.4 Experiments with Different Number of Light Sources n
5.2.5 Experiments with Different Number of Superpixels ms
5.2.6 Cast Shadows
5.3 Relighting Results
5.3.1 Lighting Design
Chapter 6. Conclusion
6.1 Summary of Attempts and Achievements
6.2 Unanswered Questions or Future Work
Index
Bibliography