Illumination and Color in Computer Generated Imagery

ISBN-13: 9781461281412 / Angielski / Miękka / 2011 / 282 str.

Roy Hall

Opis

In a very broad sense the historical development of computer graphics can be considered in three phases, each a giant step down the road towards "realistic" computer generated images. The first, during the late 1960's and early 1970's, can perhaps be characterized as the "wire frame" era. Basically pictures were composed of lines. Considerable em phasis was placed on "real time" interactive manipulation of the model. As models became more complex and as raster technology developed, eliminating the hidden lines or hidden surfaces from the image became critical for visual understanding. This requirement resulted in the second phase of computer graphics, the "hidden surface" era, that developed during the 1970's and early 1980's. The names associated with hidden surface algorithms read like a who's who of computer graphics. The cul mination of the hidden surface era and the beginning of the current and third era in computer graphics, the "rendering" era, was Turner Whitted's incorporation of a global illumination model into the ray trac ing algorithm. Now the goal was not just to generate an image, but to generate a realistic appearing image."

Spis treści

1.0 Introduction.- 1.1 Intent and Overview.- 1.2 The Process of Creating Images.- 1.3 Representation or Simulation of Reality.- 2.0 The Illumination Process.- 2.1 Light and Materials.- 2.2 Background Optics and Physics.- 2.2.1 Vector Notation.- 2.2.2 The Wave Nature of Light.- 2.2.3 Illuminating Hemisphere and Solid Angle.- 2.2.4 Intensity and Energy.- 2.2.5 Reflection and Refraction.- 2.2.6 Geometry of a Surface.- 2.2.7 Geometric Attenuation.- 2.3 Surface Illumination.- 2.3.1 Coherent Illumination.- 2.3.2 Incoherent Illumination.- 2.3.2.1 Incoherent Mechanism.- 2.3.2.2 Microfacet Distribution.- 2.3.2.3 Computing Incoherent Illumination.- 2.3.2.4 Ideal Diffuse Illumination.- 2.3.3 Emissive Illumination.- 2.3.4 A Generalized Illumination Expression.- 3.0 Perceptual Response.- 3.1 Describing Color.- 3.2 Colorimetry.- 3.3 Colorimetry and the RGB Monitor.- 3.4 Alternate Color Representations.- 3.5 Color Spaces for Color Computation.- 3.5.1 Computation in RGB.- 3.5.2 Spectral Sampling Approaches.- 3.5.3 Sources of Confusion.- 4.0 Illumination Models.- 4.1 Shading and Illumination Basics.- 4.1.1 Starting from the Eye.- 4.1.2 Starting from the Light.- 4.1.3 Combined Techniques.- 4.2 Incremental Shading, Empirical Models.- 4.2.1 Diffuse Illumination.- 4.2.2 Atmospheric Attenuation.- 4.2.3 Specular Highlights.- 4.2.4 Geometric Smoothing.- 4.3 Ray Tracing, Transitional Models.- 4.3.1 Improved Specular Reflection.- 4.3.2 Macroscopic Surface Properties.- 4.3.3 Recursive Reflection and Refraction.- 4.3.4 Distributed Ray Tracing.- 4.4 Radiosity, Analytical Models.- 4.4.1 An Energy Equilibrium Illumination Model.- 4.4.2 Radiosity for Diffuse Environments.- 4.4.3 Radiosity for Specular Environments.- 4.5 Hybrid Techniques.- 4.5.1 View Independent Illumination.- 4.5.2 View Dependent Illumination.- 4.6 Visual Comparison.- 4.7 Summary.- 5.0 Image Display.- 5.1 Image File Considerations.- 5.1.1 Color Correction for Display.- 5.1.2 Gamma Correction for Display.- 5.1.3 Color Clipping and Compressing for Display.- 5.1.4 Image Dither and Patterning.- 5.2 NTSC and RGB Video.- 5.3 Video Setup for Image Display.- 5.4 Monitor Alignment and Calibration.- 5.5 NTSC Limitations.- 5.6 Black and White Display.- Appendix I Terminology.- Appendix II Controlling Appearance.- II.1 Surface Character.- II.1.1 Dielectric Materials.- II.1.2 Conductive Materials.- II.1.3 Composite Materials.- II.1.4 Using Published Spectral Data.- II.2 Surface Finish.- Appendix III Example Code.- III.1 Geometric Utilities.- III.1.1 Code Summary.- III.1.2 Code Source.- III.2 Hemispherical Integrator.- III.2.1 Code Summary.- III.2.2 Code Source.- III.3 Geometric Attenuation.- III.3.1 Code Summary.- III.3.2 Code Source.- III.4 Microfacet Distributions.- III.4.1 Code Summary.- III.4.2 Code Source.- III.5 Fresnel Approximation.- III.5.1 Approximation Methodology.- III.5.2 Code Summary.- III.5.3 Code Source.- III.6 Illumination Models.- III.6.1 Illuminated Surface Description.- III.6.2 Code Summary.- III.6.3 Code Source.- III.7 Color Transformation.- III.7.1 Material Data.- III.7.2 Code Summary.- III.7.3 Code Source.- III.8 Spectral Sampling.- III.8.1 Code Summary.- III.8.2 Code Source.- III.9 RGB Color Cupping.- III.9.1 Code Summary.- III.9.2 Code Source.- Appendix IV Radiosity Algorithms.- IV.1 Pseudocode Definition.- IV.2 Hemi-cube Form Factors.- IV.3 Specular Radiosity.- IV.4 Hybrid Form Factors.- Appendix V Equipment Sources.- References.