中波红外与长波红外推扫成像性能分析

基于长线阵中波红外和长波红外探测器的推扫成像技术,是实现高空间分辨率和高温度分辨率卫星对地观测的技术途径之一。随着长线阵红外探测器的发展,该技术受到高度关注,并已在一些领域得到应用。介绍了中波红外和长波红外谱段成像特点以及基于长线阵中波红外和长波红外探测器的卫星推扫成像技术发展现状。重点根据中波红外和长波红外谱段的波长、温度为300 K 目标的辐射强度以及光学系统和探测器参数,分析了它们的成像性能,包括调制传递函数(MTF)、地面像元分辨率(GSD)和噪声等效温差(NETD)。对于常温目标,在积分时间足够长的情况下,保持相同的MTF,中波红外比长波红外推扫成像可实现更高的空间分辨率和温度分辨率。结合分析结果,对充分发挥这两个谱段的成像性能提出了建议。

Performance analysis on MWIR and LWIR pushbroom imaging

Pushbroom imaging technology based on long linear array MWIR and LWIR detectors is one of the major technical solutions to achieve high spatial resolution and high temperature resolution satellite earth observation. With the development of long linear array infrared detectors, great attention has been given to this technology and it has been applied in some areas. The characteristics of MWIR and LWIR imaging were introduced. The current status of satellite pushbroom imaging based on long linear array MWIR and LWIR detectors was presented. Emphasis was put on the analysis of MWIR and LWIR imaging performances, including modulation transfer function (MTF), ground sampled distance (GSD), and noise equivalent temperature difference (NETD), according to their wavelength, radiation intensity of object with a temperature of 300 K, and parameters of optics and detectors. For objects with ambient temperature, if integration time was long enough, the MWIR pushbroom imaging can achieve higher spatial resolution and temperature resolution than LWIR under the same MTF. Some suggestions for improving MWIR and LWIR imaging performances were given according to the analysis result.