红外成象器可从背景中检测出红外辐射,并将其转变为此背景的活动图象。为了使其灵敏度足以能分辨微小的温度差异,探测器必须致冷,使其所观察的每个目标都是一个热源。传统的做法是使高压纯净空气通过探测器附近的一个直径极其细微的小孔进 The infrared imager detects infrared radiation from the background and transforms it into a moving image of this background. In order to be sensitive enough to distinguish small temperature differences, the detector must be allowed to cool so that each target it observes is a heat source. The traditional approach is to make high-pressure pure air through the detector near a very small diameter hole