为解决传统大视场高分辨相机光学系统复杂、成本高昂等问题,利用同心多尺度计算成像系统,通过图像处理方式校正简化的光学结构残留的球差和倍率色差.分析光学系统的像差特性,得到不同波长的成像数据,并根据系统参量和像差表现,用红、绿、蓝三通道分别校正方案对图像进行处理.首先采用非线性图像缩放法,统一不同色光的放大倍率,完成倍率色差的校正;然后针对光学系统的点扩散函数随空间位置变化的特性,对各通道模糊图像进行分块,用Lucy-Richardson算法对每一个图像块进行图像复原,完成单色像差校正;最后融合三通道获得校正图像.用均方误差、峰值信噪比和结构相似度等方法进行图像质量评价,结果表明本文方法能够有效校正计算成像系统中的残留像差,提升图像质量.

Monocentric multiscale computational imaging system was used to solve the problems of high complexity and cost in traditional wide-field high-resolution camera.Image processing was used to correct the plenty of aberrations caused by the simplified optical system,especially the spherical aberration and the lateral chromatic aberration.The aberration characters were analyzed to get the imaging data.The image was processed separately in red,green and blue channels using the system parameters and the aberration manifestation.Firstly,a non-linear image scaling method was used to harmonize the magnifications of different colors so that the lateral chromatic aberration is corrected.Then,the blurred image of different channels was divided to sub-frame sections because of the space-variant point spread function of the optical system.The sub-sections were restored by Lucy-Richardson algorithm so that the monochromatic aberrations is corrected.At last,the images in red,green and blue channels were fused to be the corrected image.The imaging and correction process was simulated and the image quality was assessed by mean squared error,peak signal to noise ratio and structural similarity.The results show that the aberration caused by the computational imaging system can been corrected effectively and the image quality can been improved.