The Computation of Surface Lightness in Simple and Complex Scenes

...................................................................................................................................... i Acknowledgements .................................................................................................................... ii List of Publications .................................................................................................................... iii List of Figures ............................................................................................................................ vi List of Tables ........................................................................................................................... viii Chapter 1. Determining how the Visual System computes Surface Lightness in Complex Scenes .............................................................................................................................. 1 Classes of Lightness Theories ................................................................................................. 4 Brightness Models ........................................................................................................................... 5 Framework models ....................................................................................................................... 10 Decomposition models ................................................................................................................. 11 Relating Existing Lightness Theories to Real-World Scenes ................................................. 17 Potential Information about Lightness Available in Real-World Scenes ............................. 19 Shading, cast shadows and specular highlights ............................................................................ 19 Texture caused by complex mesostructure .................................................................................. 24 Unanswered Questions ........................................................................................................ 26 Chapter 2. Do Surface Reflectance Properties and 3D Mesostructure influence the Perception of Lightness? ................................................................................................. 29 Experiment 1A and 1B: Varying Surface Relief and Gloss Level of the Surround ................ 30 Methods ........................................................................................................................................ 30 Results and discussion .................................................................................................................. 41 Experiment 2A and 2B: Variegated Surrounds .................................................................... 50 Methods ........................................................................................................................................ 51 Results and discussion .................................................................................................................. 54 Experiment 3: Flat, Matte Adjustable Surface ..................................................................... 57 Methods ........................................................................................................................................ 57 Experiment 4: Phase-Scrambled Surrounds ......................................................................... 62 Methods ........................................................................................................................................ 62 Results and discussion .................................................................................................................. 64 Concluding Thoughts ............................................................................................................ 66 Chapter 3. The Role of Interreflections on Lightness Perception under Changing Illumination Level ........................................................................................................... 69