结合长期从事光电跟踪仪器研制的实践，针对低飞小目标远距离跟踪测量的特点，从跟踪信号的大小及其对比度两个方面分析了它们对电视作用距离的影响.深入探讨了目标穿越电视机场产生的动态对比度及其对作用距离的影响.并提出采用电子快门和光谱匹配技术提高目标信号对比度，提高电视跟踪作用距离的方法.

The influence on the TV tracking effective ranging in regard to both the signal and the forget-to-background contrast is analysed on the features of long-distance tracking and measuring of the target travelling at low altitude, based on the experience in development of opto-electronic tracking and measuring instrument. The discussion is emphasized on the dynamic contrast formed as the target passing across the TV field of view and its influence to the effective ranging. A method is proposed to improve the dynamic target-to-background contrast and to expand the TV tracking effective ranging by adopting electronic shutter and spectral matching techniques.