直视合成孔径激光成像雷达内发射场波前像差对成像的影响  

Influence of Inner Wave-front Aberration on Down-Looking Synthetic Aperture Imaging Ladar Imaging

作　　者：卢智勇[1] 孙建锋[1] 职亚楠[1] 周煜[1] 栾竹[1] 张宁[1] 刘立人[1] 

机构地区：[1]中国科学院上海光学精密机械研究所中国科学院空间激光信息传输与探测技术重点实验室,上海201800

出　　处：《光学学报》2014年第7期243-252,共10页Acta Optica Sinica

基　　金：国家自然科学基金(61275110;61377004;61108069)

摘　　要：直视合成孔径激光成像雷达采用内发射场直接波面变换平动扫描发射,通过自差接收实现高分辨率成像。由于远场目标位置的光场分布取决于内发射光场,因此内发射场的波前像差会对激光雷达图像质量产生影响。采用Zernike多项式描述波前像差,对初级像差造成直视合成孔径激光成像雷达的成像影响进行了研究,理论分析和仿真结果表明:离焦、象散、彗差和球差对成像的影响最为严重,像差越大,其对成像分辨率的影响也越大。当像差的均方根值小于0.05λ时,对成像分辨率的影响很小,当像差的均方根值为0.25λ时,其象散和彗差引起成像分辨率近似增大到原来的3倍。彗差和球差还造成不同目标位置的成像分辨率不同,离中心位置越远,成像分辨率增加越快。Down-looking synthetic aperture imaging ladar （SAIL）, with a transmitter of direct wave-front transformation in inner optical fields by parallel scanning, makes use of self-heterodyne detection to improve the resolution of images. Wave-front aberration in inner optical fields has effects on the imaging quality of the down- looking SAIL because the optical fields on the target plane depend on the inner optical fields at the focal plane of main lens. Zernike polynomials are proposed to represent wave-front aberrations. The influence of primary aberrations on down-looking SAIL imaging is investigated. The results show that focus, astigmatism, coma and spherical aberrations have significant influence on imaging, and the deeper the aberrations are, the more significant the influence on the resolution of images is. When the root mean square （RMS） value of primary aberrations is less than 0.05λ, the influence on resolution of images is very small. When the RMS value is up to 0.25λ, the resolution of images is up to 3 times in the condition of astigmatism and coma aberrations. Meanwhile, the target pointing at different positions has different resolutions with coma and spherical aberrations. The further the imaging targets from the center position are, the more significant the influence on the resolution of images is.

关 键 词：遥感 直视合成孔径激光成像雷达 波前像差 内发射场 ZERNIKE多项式 

分 类 号：TN958[电子电信—信号与信息处理]