摘要
消除综合孔径望远镜子孔径之间的相对光程差是实现高分辨率干涉成像的前提条件,条纹检测法是一种检测相对光程差的有效办法。因子孔径的空间位置排布使干涉条纹具有一定的方向性,若不能精确获知干涉条纹的角度,则无法沿条纹的法线方向行采样,进而无法根据对比度变化曲线的最大值获得子孔径之间的最小光程差位置。提出了一种基于傅里叶变换和图像二值化阈值遍历的获得干涉条纹角度的方法,首先介绍了算法的基本原理,其次通过对条纹角度为43°的仿真数据进行算法验证得到的角度为43.007 8°,与理论值的误差为0.018%,证实了方法的可行性。最后对比了未旋转相机和旋转相机两种情况下的条纹对比度变化曲线,可知通过旋转相机使条纹转至相机靶面纵轴方向再进行采样的办法,更有利于精确得到相对光程差的最小位置。
Eliminating the relative Optical Path Difference （OPD） between two sub-apertures in synthetic aperture telescope is a precondition for high resolution image. The fringe detection method is effective to decrease the relative OPD. The fringe angle depends on the position distribution of sub-aperture. The precise angle of fringe is an essential prerequisite for taking line sample along the normal direction. And then, on the basis of the maximum contrast value, the position corresponding to the minimum OPD between two sub- aperture can be obtained. Here, a method for calculating the angle of interference fringes based on Fourier transform and threshold traversal of image binaryzation is proposed. Firstly, the basic principle of the algorithm is introduced. Secondly, with the data for fringe angle of 43 degrees as the simulation data to test this algorithm, the result of 43.007 8 degree is obtained. The value of error is 0. 018% compared with theoretical simulation value. In the end, contrast curves from two cases of rotating camera and non-rotating camera are compared. It is more benefit to get the accurate minimum OPD by the method of rotating camera to make the fringe along the longitudinal axis of camera according to the angle of fringe.
作者
王超燕
陈欣扬
郑立新
李可新
蔡建清
丁媛媛
Wang Chaoyan Chen Xinyang Zheng Lixin Li Kexin Cai Jianqing Ding Yuanyuan(Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, Chin)
出处
《天文研究与技术》
CSCD
2017年第3期369-375,共7页
Astronomical Research & Technology
关键词
傅里叶变换
阈值
干涉条纹
条纹角度
光程差
Fourier Transform
Threshold
Interference fringe
Fringe angle
Optical path difference
