Joint chromatic aberration correction and color fringe removal for variable aperture optical system

Abstract

In this paper a novel way to correct chromatic aberration and remove the color fringe for variable aperture optical system considering the physical causes is proposed. From the perspective of the correlation between chromatic aberration and aperture, we explain why image fusion with different aperture parameters can effectively remove color fringing. Then we propose a specific color fringing detection and image fusion process. First, we detect the overexposed area of the large aperture image, perform grayscale grading on its neighborhood, extract the edges, and expand to obtain the candidate color fringing region. Then the two images are transformed to YCbCr color space to extract the purple fringe area by comparing the color information of the candidate color fringe area. Finally, we use the Cb and Cr channels of the small aperture image to correct the corresponding channels in the color fringing area and retain the brightness of the original image. Through image fusion, we can remove the color fringing caused by axial chromatic aberration and sensor crosstalk, and the residual lateral chromatic aberration can be corrected by simple image warp. Compared with the traditional blind restoration of color fringe regions, our method uses the hue information of small aperture image as a reference and no artifact is introduced. Experimental results show that both the subjective visual effects and objective evaluation have been significantly improved.