遥感图像恢复与遥感器MTF 在轨检测技术

遥感成像过程受到大气和成像系统中的光学、探测器和电子学子系统等的影响, 引起成像退化作用, 造成图像模糊, 降低了图像中信息的提取能力。图像恢复技术可以改善图像的质量, 提高图像信息提取能力。依据图像恢复技术的要求, 高精度成像系统调制传递函数(MTF) 是高质量图像恢复的基本条件。针对不同遥感器之间、同一遥感器不同时期存在的成像性能变化, 所引起成像系统MTF 变化的实际情况, 介绍了成像过程中系统MTF 在轨运检测方法。着重于介绍刃边法, 对刃边法的原理、刃边法检测对地物景观的要求等进行了详细分析, 对这一方法中有关图像景物的行扫描采样、扫描行的配准以及对所获得的边扩散函数的拟合等关键技术进行了详细介绍, 这些技术是保证较高精度获取遥感图像MTF 的基础。文章在介绍基于成像系统MTF 图像恢复技术后, 通过实验检验了方法的可行性, 结果表明以MTF 在轨检测为基础的图像恢复技术, 可以明显地提高遥感图像质量。

A Technique of RS Image Restoration and In-flight Measurement of Remote Sensor MTF

Due to effects of atmosphere and optical subsystem,detector and electronic subsystem in imaging system,there is degradation in imaging process.The degradation of imaging system induces imagery blur.The ability to acquire information from blurred image is debased The technique of image restoration can improve imagery quality,so it can enhance the ability to acquire information from restored image.According to the requirement of image restoration technique,high precision modulate transfer function(MTF) of imaging system is the base of high-quality imagery restored.Since there are differences of MTF between different remote sensors and at different period of same remote sensor,it is important to acquire MTF of imaging system in-flight.The paper presents systematically a in-flight measurement technique of remote sensor MTF,which is called knife edge technique.In the technique,we first analyze its principle and its requirement on targets in images,then introduce in detail several key techniques including sampling method line by line in image,registering line pixels with shifted knife method and fitting method to acquired knife edge.After introducing the technique of image restoration based on imaging system' MTF,the paper shows the improved image on the bases of experiment.The result appears imagery quality is improved obviously.