空间相机的颤振成像调制传递函数及仿真实验

摘要

为实现对卫星平台力学环境的合理约束,研究了空间相机颤振与成像调制传递函数(MTF)下降的关系.通过理论分析,建立了基于统计矩的颤振传递函数的数学模型,实现了在特定函数振动和已知振动曲线情况下对MTF下降曲线的计算.针对某空间相机,利用MATLAB软件的图形用户接口(GUI)编制了颤振成像MTF计算软件,计算了在有随机噪声的正弦型振动情况下不同振动幅值和频率对应的MTF值,得出该相机对于平台颤振的要求为:在0.04 ms积分时间内其振动角幅值小于0.05″,并避免相机产生200 Hz以上的振动.通过半物理仿真实验,对非函数形式的任意振动导致的传递函数下降进行深入分析,在图像的像质退化与振动传递函数之间建立了联系.用图像分析的方法计算了传递函数,结果与数学模型计算得到的传递函数趋势一致.%The relationship between the vibration of a space camera and its Modulate Transfer Function (MTF) degeneration is investigated. A suitable limitation for a satellite platform is developped through this research. Mathematical modeling of a vibrating MTF is calculated based on a vibration moment method. The MTF curve can be deduced from the vibration functions or curves. The vibrating MTF calculations uses Graphic User Interface (GUI) to develop an software for some space cameras. MTF values under sinusoidal vibrations contain random noise and are calculated with different amplitudes and frequencies. Requirements of the satellite platform vibration is that the angle amplitude of vibration must be less than 0. 05", and the vibration frequency should not be more than 200 Hz. MTF degeneration caused by random vibration is analyzed by simulation to relate image quality degeneration with MTF vibration. Image analysis for the MTF shows good agreements with the MTF calculated by the vibration model.