Defocus morphing in real aperture images

Abstract

We introduce a new concept called defocus morphing in real aperture images in this paper. View morphing is an existing example of shape preserving image morphing based on the motion cue. We prove that images can also be morphed based on the depth related defocus cue. This illustrates that the morphing operation is not necessarily a geometric process alone; one can also perform a photometry based morphing wherein the shape information is implicitly buried in the image intensity field. A theoretical understanding of the defocus morphing process has been presented in this paper. Mathematically we show that, given two observations of a 3D scene for different camera parameter settings, we can obtain a virtual observation for any camera parameter setting through a simple nonlinear combination of these observations.

A Layer-Based Restoration Framework for Variable-Aperture Photography

“…Initial layering and blur assignment. To obtain an initial estimate for the layers and blur diameters, we use a simple window-based depth-from-defocus method [18,9]. This method involves directly testing a set of hypotheses for blur diameter, specified in the widest aperture, by synthetically defocusing the image as if it were a fronto-parallel scene.…”

“…Although the output of these methods theoretically permits post-capture refocusing and aperture control, most of these methods assume an additive, transparent image formation model [19,14,21] which causes serious artifacts at depth discontinuities, due to the lack of occlusion modeling. Similarly, defocus-based techniques specifically designed to allow refocusing rely on inverse filtering with local windows [4,9], and do not model occlusion either. Importantly, none of these methods are designed to handle the large exposure differences found in variable-aperture photography.…”