Free Iris Scene Re-Focusing Based on a Three-Dimensional Filtering of Multiple Differently Focused Images

This paper describes a method of scene re-focusing with various iris shapes by integrating a sequence of multiple differently focused images. First, we introduce a formula that combines the sequence and spatial information of a scene with a convolution of a 3-D blur. The blur expresses how the scene is defocused in the sequence. Based on the formula, in the 3-D frequency domain we can design filters merging certain frequency components of the sequence to generate images that would be acquired with various iris shapes. Some experiments of scene re-focusing using synthetic and real images indicate that we can not only arbitrarily suppress blurs of the sequence but also generate images with asymmetrical blurs like motion blurs.