Shading Flashcards
Shading is
Variation in brightness due to changes in surface orientation
Shape from shading is
Recover the shape of a surface based on intensity variation
Photo metric stereo
Single viewpoint, multiple images under different lighting effects
Radiometry
How bright will surface be?
Thinking about how light will arrive at a surface
Foreshortening
The projection looks smaller as it’s rotated out of plane
Solid angle
Area of unit sphere intersected by the cone
If I’m a point solid angle tells me how much I can view
Radiance, L
Power emitted from surface patch
Radiance is constant along a straight line
Irradiance, E
Power falling on a surface patch
Function of incoming angle
Reflectance
The way light interacts with a surface
Is a whole Corel’s go study on its own
What can happen when a light ray hits an object?
Absorbed
Transmitted through
Reflected
Bidirectional reflectance distribution function BRDF
Ratio of radiance in the outgoing direction to the incident irradiance
Tells how bright a surface appears when viewed from one direction while light falls on it
From another
Surface reflectance
Diffuse reflection
Matte appearance
Specular reflection
Mirror like
Albedo of surface (reflection coefficient)
Diffuse surface reflection
Lambertian surfaces, reflect uniformly
Specular surface reflection
Phony’s model of specular reflection
