Paper
4 August 2009 The experimentation research of IR imaging system capability affected by sapphire window's pneumatic calefaction
Yang-peng Liu, Guo-qing Pan, Yun-qiang Zhang
Author Affiliations +
Abstract
In the inclement pneumatic calefaction condition, the window of IR imaging system will be calefied and emit infrared radiation, so that the Signal-to-Noise and quality of target IR image are felled off that are from the imaging system. At this rate the physical characteristic of IR window direct affect capability of imaging system controlled and guided homing by IR tracker and measure precision of target IR characteristics. The properties of sapphire make it an ideal choice for the high speed missile applications compared to other existing or emerging materials. But the research has not been reported about the infrared radiation characteristic of sapphire as the IR window. In this paper, based on an IR imaging system using the sapphire window, the experimentation and conclusions of IR thermal image measurement affected by IR window's pneumatic calefaction have been accomplished. Firstly, the temperatures of sapphire window at supersonic flight extended over 1 km and 15 km from the ground have been estimated by calculating the flow and state variables and the aerodynamic heating into the window. On the base of the results calculated the window static state calefaction experimentation and electric arc wind tunnel experimentation had been designed and completed to validate the effect degree of pneumatic calefaction to the imaging system. With the temperatures of the sapphire window rising, in the image coming from the imaging system, the peak luminance of target image detected is increased, the background average luminance of the image is also increased, and the margin of above two varies in a little range. The data obtained from the different temperature experimentation have demonstrated that the IR flux due to the sapphire window becomes heated by friction with the air and heat transfer to the dome can obscure the target image created by the onboard IR sensor, depress Signal-to-Noise and resolving power of the imaging system, but can not overload the detector.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yang-peng Liu, Guo-qing Pan, and Yun-qiang Zhang "The experimentation research of IR imaging system capability affected by sapphire window's pneumatic calefaction", Proc. SPIE 7383, International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, 73831E (4 August 2009); https://doi.org/10.1117/12.835584
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KEYWORDS
Infrared imaging

Imaging systems

Sapphire

Domes

Missiles

Thermography

Infrared radiation

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