Focal Stack Representation and Focus Manipulation

Parikshit Sakurikar, P. J. Narayanan

Abstract: Focus, depth-of-field, and defocus are important elements that portray the aesthetic emphasis in a good photograph. The ability to manipulate the focus after capture provides useful creative control to photographers. Capturing focal stacks - multiple images with small change in focus setting - of static scenes is relatively easy with modern cameras. We propose a compact representation for focal stacks using an all-in-focus image, a focal-slice index map and pair-wise defocus blur parameters. Using our representation, we show reconstruction of images with different focus effects including extended focus, multiple focus, and scene synthesis with natural focus effects. A user study shows high acceptability of the synthesized images compared to real ones. The compact and powerful representation of focal stacks makes them suitable for handling by image editing tools in order to provide flexible focus manipulation.