论文部分内容阅读
卡塞格林光学遥感系统相当于一个望远系统和环形光阑的组合,无穷远物的夫琅禾费衍射谱是圆孔衍射和圆屏衍射共同作用的结果。由于系统次镜中心遮拦的影响,损失了一部分衍射谱,造成了系统调制传递函数(MTF)在中频段的下降,影响了成像质量。设计了一个2 m焦距的改进型卡塞格林光学系统。为了弥补系统成像质量的损失,运用调制传递函数补偿(MTFC)技术,通过倾斜刃边法提取卡塞格林系统所拍摄图像的点扩展函数(PSF),对退化图像进行复原,并利用多种客观图像质量评价函数对复原效果进行了评价。实验结果表明,该方法对于卡塞格林系统成像质量的提高具有良好效果。
The Cassegrain optical remote sensing system is equivalent to a combination of a telephoto system and a circular aperture. The Fraunhofer diffraction spectrum of infinity is the result of a combination of circular aperture diffraction and circular diffraction. Due to the influence of the secondary lens center of the system, a part of the diffraction spectrum is lost, resulting in a decrease of the system modulation transfer function (MTF) in the middle frequency band, which affects the imaging quality. An improved Cassegrain optical system with a focal length of 2 m was designed. In order to compensate for the loss of the quality of the imaging system, MTF (Point Transfer Function) is used to extract the point spread function (PSF) of the images taken by the Cassegrain system by tilted edge method to recover the degraded images. The image quality evaluation function evaluated the recovery effect. Experimental results show that this method has good effect on the imaging quality of Cassegrain system.