IR radiation imaging test, process and evaluation of jet aeroengine

The infrared(IR) signature is the important basis for IR stealth design and anti-stealth detection of jet aero-engine. There were three major contributions in this paper. Firstly, the jet aero-engine had a wide temperature span to be measured, which was far too large for an IR camera to cover in one snapshot. This was accomplished by using multi-integral time combined measure method, each integral time was optimized to a definite range of temperature and to make sure that the combination of all integral times seamlessly covered the entire temperature range of target. Secondly, the measured temperature range of each integral time was defined by multi-frame image time-averaging method, then a per-pixel radiance replacement and images synthesization method was proposed to form an integrated IR image. Compared with IR image of single integral time, the integrated image shows abundant target details and signature information. Finally, the distribution of IR radiant intensity was calculated, compared with IR spectroradiometer measurement at the same test-point, and error was less than 10%. The result shows that proposed methods based on IR camera are all reasonable and efficient.