摘要
相位误差的存在严重降低了光学合成孔径系统的成像质量。针对活塞误差和倾斜误差的不同特性,设计对应的量化指标,并以维纳滤波进行复原,利用相关系数进行评价。统计结果表明,只有活塞误差均值小于0.06λ,倾斜误差均值小于16μrad时,才能保证相关系数大于0.98,近似实现无损复原。在此基础上,通过旋转阵列获取频谱不同的多帧图像共同参与复原,以减小或消除相位误差的影响。比较不同旋转角度和次数情况下的复原结果,最终确定最优方案。实验结果表明,该方法与直接成像相比,可以显著提高含相差系统的图像复原质量,而且将两种相位误差容限分别提高到0.12λ和35μrad,降低了对光学设计和相差校正的精度要求。
The existence of phase errors severely decreases the imaging quality of optical synthetic aperture system. The quantified scales are designed for the various characteristics of piston error and tip/tilt error. Moreover, Wiener filter and correlation coefficient are opted as restoration and assessment method. Statistic results demonstrate the value of correlation coefficient can be guaranteed beyond 0.98 on condition that average piston error is less than 0.06λ and average tip/tilt error is less than 16 μrad. Furthermore, the method of rotating the array and acquiring multiple images with various spectra is utilized to reduce or eliminate the effects of phase errors. An optimized scheme is brought out by comparing the restoration results of various rotation angles and times. The experimental result shows that the proposed method can dramatically increase the restoration quality of imaging system with phase errors. The phase error tolerances can be improved to 0.12λ and 35 μrad, respectively, which means the precision demand of optical design and phase error correction is decreased.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第4期98-104,共7页
Acta Optica Sinica
基金
国家863计划
关键词
成像系统
光学合成孔径
相位误差
旋转阵列
相关系数
误差容限
imaging systems
optical synthetic aperture
phase error
rotated array
correlation coefficient
errortolerance
