Discussion on the Operation Range Equation of the Infrared Imaging System for Point Target Based on NETD and △T

摘要

Analysis on the conception and mathematical deducing of Noise Equivalent Temperature Difference (NETD), as well as the tenable conditions of the operating range equation considering the temperature difference between the target and the background (△T) and NETD is given. It turns out that the mathematical expression of NETD, the experimentally measured value of NETD, and the operation range equation are under the condition that the temperature difference between the target and background is small. But in fact, the small temperature difference condition are not always fit for the target detected as a point. Therefore it is not suitable to calculate the operation range of the infrared imaging system by applying the conception of NETD. Lastly, a method based on NETD and the respective temperature of target and background to calculate the operating range for spot target is introduced.