Pyrometer #2

An instrument adapted to be disposed remotely from a diffusely reflecting target heated to radiance and comprising:

• first means responsive to that portion of target radiance which reaches the instrument to produce a first electrical signal monatonically related thereto;
• second means to generate a laser beam and to direct said beam upon the target, a portion of the energy delivered to the target by the beam being reflected back to said instrument;
• third means responsive to said reflected energy portion to produce a second electrical signal monatonically related thereto;
• fourth means for measuring the separation between target and instrument to produce a third electrical signal monatonically related thereto;
• fifth means responsive to said beam to produce a fourth electrical signal monatonically related to the power level of the generated laser beam;
• and
• sixth means for
• responding to said second and third signals to compute therefrom a fifth signal monatonically related to said second signal as corrected for separation in accordance with the third signal;
• responding to said fifth signal and said fourth signal to compute the ratio of said fifth signal to said fourth signal;
• computing from said ratio the target emissivity;
• responding to said first signal and said emissivity to compute the surface temperature of said target.