Analysis of emissivity effects on target detection through smokes/obscurants

W. Michael Farmer

doi:10.1117/12.55984

1 November 1991 Analysis of emissivity effects on target detection through smokes/obscurants

W. Michael Farmer

Author Affiliations +

Optical Engineering, Vol. 30, Issue 11, (November 1991). https://doi.org/10.1117/12.55984

Abstract

The magnitude of target thermal contrast is used as a key parameter in determining whether observers using thermal-imaging systems can detect military targets. The effects of differences in target and background emissivities on thermal contrast estimates are evaluated, and the effects these differences have on the estimate of the transmittance attenuation thresholds required to obscure a target viewed with a thermal imager are examined. Target-background radiometric difference in the thermal infrared bands is first computed in terms of target-background emissivities and thermodynamic temperatures; the result is then used to compute a difference function for brightness temperature relative to thermodynamic temperature as a function of the target-background emissivity ratio. The effect of emissivity differences between targets and backgrounds on smoke/obscurant attenuation required to obscure a target viewed with a thermal imager is then examined using an expression derived from the Center for Night Vision and Electro-Optics Static Performance model. Results of the analysis show that smoke screen requirements for obscuring targets from thermal imager detection can change by factors of 10 as the ratio of target-to-background emissivity changes by less than 25%.

Citation Download Citation

W. Michael Farmer "Analysis of emissivity effects on target detection through smokes/obscurants," Optical Engineering 30(11), (1 November 1991). https://doi.org/10.1117/12.55984

Published: 1 November 1991

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available