【摘要】 在采用矩形靶标测量航天相机系统MTF时,由于采样初始时刻靶标像与CCD像元间存在配准误差,因此给准确测量系统MTF带来很大困难。为了减小配准误差对测量的影响,提出了采用粗分与细分相结合的梯形靶标,并推导出在奈奎斯特频率下动态测量调制传函时,由采样初始时刻配准误差所引起的配准误差调制传递函数MTF计算公式,并按此公式分别得到了粗分精度和靶标斜率对测量相机系统MTF精度的影响。通过分析,采用梯形靶标可以有效减小配准误差对测量系统MTF的影响,提高测量精度。更多还原

【Abstract】 When using rectangles as the target,it’s difficult to measure the Modulation Transfer Function(MTF) of the space camera accurately because of the registration error between the image of the target and the pixel of the CCD at the initial sampling.To reduce the effect of the error,trapezoidal target is used,which includes both rough division and subdivision.Then,the formula of the error MTF,which results from the initial registration error,is deduced under the Nyquist frequency.From which,the effects of the rough-division precision and the target slope on the measurement accuracy of the MTF are discussed respectively.Analytical results show that: when using the trapezoidal target,the influence of the registration error can be reduced effectively and the measurement accuracy of the MTF can be improved greatly.更多还原