针对火箭起飞过程中零时信号难以准确测量问题，提出了激光主动成像与距离选通技术相结合的测量方式，并通过求取光流的变化进而求取位移移动量获得火箭起飞的零时信号。对现有的零时信号测量方式进行了分析，确定了基于距离选通的ICCD成像方式，结合目标垂直上升的特性，提出目标轮廓与HS光流结合的抗光照干扰算法。实验结果表明：在模拟目标匀速上升过程中，在光照变化不大情况下，单独的边缘检测及单独的HS光流检测算法均能检测出目标的上升趋势；在光照变化剧烈情况下，边缘检测及HS光流检测算法均出现严重的误差，目标轮廓与HS光流结合算法排除了目标内部的干扰，得到的目标像素点位移量与真实的上升量基本一致，误差在亚像素量级，若图像帧频为25 fps，则时间精度为80 ms，完全符合零时信号提取的要求。

To accurately measure the zero signal of rockets during takeoff, a measurement method was put forward herein combining laser active imaging and range-gated technology, under which the zero signal was obtained by calculating the change in optical flow and then the amount of displacement. Existing zero signal measurement methods were analyzed to determine the range-gated ICCD imaging method, and combined with the feature of the target rising vertically, an anti-light interference algorithm was proposed combining the target contour and HS optical flow. Results show that as the simulated target is rising in uniform velocity, when the light changes little, either edge detection or HS optical flow detection algorithm could detect the upward trend of the target independently; when the light changes drastically, both edge detection and HS optical flow detection algorithm show serious errors, while edge detection combined with HS optical flow algorithm eliminates the interference inside the target, and the target pixel displacement amount obtained is basically consistent with the real ascending amount with the error in sub-pixel. If the image frame frequency is 25 fps, the time accuracy is 80 ms, which is in full compliance with the requirements of zero signal extraction.