光学学报, 2019, 39 (7): 0728006, 网络出版: 2019-07-16
基于地面周期靶标的光学遥感相机在轨调制传递函数测量方法 下载: 891次
On-Orbit Measurement of Modulation Transfer Function for Optical Remote Sensing Cameras Based on Periodic Ground Targets
遥感 采样成像系统 调制传递函数 周期靶标 拟合 remote sensing sampled-imaging system modulation transfer function periodic targets fitting
摘要
为了克服传统的基于周期靶标的在轨调制传递函数测量方法中测量精度过分依赖靶标组数的问题,通过对传统方法的原理进行深入剖析,提出了一种新的测量方法。在获得多组具有一定相位差异的地面周期靶标图像数据后,充分利用所有采样数据及相应相位关系,进行参数拟合,得到地面靶标经成像系统后的调制度,对比输入调制度计算调制传递函数。仿真及实际光学遥感相机的实验结果表明:仅利用两组靶标,理论上所提方法的测量精度可优于0.5%;测试图像噪声、靶标周期匹配偏差、测量角度匹配偏差等因素对测量误差的影响均在4%以内,该测量方法的适应性较高。所提方法的计算结果与倾斜刃边法具有良好的一致性,可以应用于高分辨率光学遥感相机的在轨调制传递函数测量。
Abstract
In traditional on-orbit modulation transfer function (MTF) measurements based on periodic targets, there is a known overdependence of the achieved accuracy on the number of target groups. The method introduced in this study aims to overcome such reliance, through a thorough analysis of the principle of the traditional method. We first collect the imaging data of multiple groups of ground periodic targets with certain phase differences and then calculate the output modulation of the imaging system by parametric fitting using all the sampling data as well as the relative phase relations. Subsequently, we compare the input and output modulations to obtain the MTF. We also perform a simulation and a series of experiments of real remote sensing cameras to assess the effectiveness of our method. The results theoretically reveal a small measurement error of less than 0.5% using only two groups of targets, whereas the errors caused by image noise and target-periodic- and measuring-angle matching deviations are less than 4%. This method has good adaptability, and is consistent with the slanted-edge method; therefore, it can be easily applied to on-orbit MTF measurements of high-resolution optical remote sensing cameras.
吴泽鹏, 曲耀斌, 赵庆广, 扈宗鑫. 基于地面周期靶标的光学遥感相机在轨调制传递函数测量方法[J]. 光学学报, 2019, 39(7): 0728006. Zepeng Wu, Yaobin Qu, Qingguang Zhao, Zongxin Hu. On-Orbit Measurement of Modulation Transfer Function for Optical Remote Sensing Cameras Based on Periodic Ground Targets[J]. Acta Optica Sinica, 2019, 39(7): 0728006.