Patent ID: 7767927

Claim:
A system for remotely measuring a temperature of a specular surface of an object having a Brewster angle and an emissivity ξ, comprising: a collection optical system having a photodetector and arranged to receive and detect P-polarized radiation emitted directly from a first side of a portion of the surface at or near the Brewster angle with said photodetector to form therefrom a first signal SA; a P-polarization-preserving retro optical system with a round-trip transmission time of t 2 arranged to receive P-polarized radiation emitted from a second side of said portion of the surface at or near the Brewster angle and retro-reflect the second side received P-polarized radiation to said portion of the surface t 2 later with said collection optical system receiving a combination of said retro-reflected and emitted directly radiations to cause the photodetector to form a second signal SB; and a controller coupled to the photodetector, the controller adapted to receive and process signals SA and SB and calculate the surface emissivity ξ=1−(SB/SA−1)/t 2 .