04/08/2003
15-462 Graphics I
8
Power at Point in a Direction
•Radiant intensity I
–Power
radiated per unit solid angle by point source
–Dimension:
power / solid angle
•Radiant intensity in direction w
– I(w)
= dP/dw
•Radiance L(x, w)
–Flux
density at point x in direction w
–Dimension:
power / (area £ solid angle)