The investigation of chromatic aberration correction for digital eye fundus images

Abstract

This paper focuses on the lateral chromatic aberration correction in images captured with Optomed SmartScope M5 camera. This portable non-mydriatic eye fundus orbital camera does not have chromatic lenses. When photo camera system is designed without chromatic lenses, it is necessary to apply image processing algorithms for lateral chromatic aberration effect correction. These algorithms try to scale the fringed colour channels so that all channels spatially overlap each other correctly in the final image. We seek to realign different colour channels. This is achieved by: finding a focus centre using Quasi-Newton method with Gaussian Blur filter to separate channels and using correction model with Levenberg-Marquardt minimization. Three different correction models were tested to eliminate the chromatic aberrations: simple (shift and scale), affine and projective.