Image 1: Separating specular and diffuse reflected light
(a) Normal image in dot lighting
(b) Image of the diffuse reflection which is caught by placing a vertical polarizer in front of the light source and a horizontal in the front the camera
(c) Image of the highlight specular reflection which is caught by placing both polarizers vertically
(d) Subtraction of c from b, which yields the specular component
Images are scaled to seem to be the same luminosity.
Original image by Debevec et al. – Copyright ACM 2000 –
http://dl.acm.org/citation.cfm?doid=311779.344855 – Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page.