A (brief) Intro to Optics

Optics is the study of light and its interactions with matter, forming the foundation of many techniques in 3D computer graphics. Understanding optics is relevant for achieving realistic rendering, accurate lighting, and authentic visual effects.

The Nature of Light

Light exhibits both wave-like and particle-like properties, known as wave-particle duality. It travels as electromagnetic waves, with visible light being a narrow band within the electromagnetic spectrum, which also includes infrared and ultraviolet radiation.

Reflection and Refraction

Reflection occurs when light bounces off a surface. Specular reflection is mirror-like, while diffuse reflection scatters light in various directions. Refraction is the bending of light as it enters different mediums, such as water or glass. Total internal reflection occurs when light cannot escape a medium, a principle used in fiber optics.

Absorption and Transmission

Materials absorb certain wavelengths and transmit or reflect others. This interaction determines color perception. Transparency refers to the ability of light to pass through a material, while opacity is its resistance to light. Translucency is partial transparency.

Optical Phenomena

Shadows are cast when light is blocked. Diffuse lighting scatters light in all directions. Ambient occlusion adds depth by darkening recessed areas. Depth of field blurs distant or near objects relative to focus. Bokeh refers to the aesthetic blur quality. The inverse square law describes how light intensity decreases with distance.

Color Theory

Primary colors (red, green, blue) combine additively to produce secondary colors. The color wheel illustrates hues and their mixing. Color spaces like RGB (additive) and CMYK (subtractive) are essential for displays and printing.

Relevance to Computer Graphics

Physically-Based Rendering (PBR) simulates real-world material properties. Ray tracing follows light paths to produce accurate images, while rasterization renders 3D scenes by projecting 2D pixels. These techniques rely on optical principles for realism.

Cameras and Lenses

Focal length and aperture control image framing and depth of field. Optical distortions like chromatic aberration and lens flares enhance realism or create effects in virtual environments.

Lighting Models

Lambertian models diffuse reflection, Blinn-Phong adds specular highlights, and Cook-Torrance incorporates microfacet theory for realistic materials. Global illumination simulates indirect lighting for immersive environments.

Optics in Photogrammetry and 3D Scanning

Cameras capture images for 3D reconstruction, requiring understanding of lens distortions. Structured light techniques project patterns to capture shape and texture.