PPT Slide
solid angle solid angle [steradian]
a two-dimensional angle (proportional to area on a sphere)
power energy/time [watt]=[joule/sec]
photons per second; radiance integrated over incoming directions, over a finite area.
radiance (intensity) power/(area*solid angle) [watt/(m2*steradian)]
how bright is the light reflected by this point along this direction (reflected light)
irradiance (intensity) power/area [watt/m2]
how bright is the light hitting the surface (or image) at this point (incident light)
what fraction of the light is reflected by a material? typically between 0 and 1.