Realistic rendering of bokeh effect based on optical aberrations

Abstract

Bokeh effect is an important characteristic for realistic image synthesis. However, existing bokeh rendering methods are incapable of simulating realistic bokeh effects due to not taking into account optical characteristics of real lenses, especially optical aberrations. In this paper, a novel realistic bokeh rendering method, based on an accurate camera lens model and distributed ray tracing, is presented. An optical analysis of the relationship between bokeh and optical aberrations, including spherical aberration, coma, astigmatism and field curvature, is firstly introduced. Based on this analysis, a physically-based camera lens model, which takes detailed lens prescription as input, is then introduced for accurately modeling the aberrations. The position and diameter of the entrance and exit pupils are calculated by tracing rays inside the lens for achieving efficient ray sampling, and a general sequential ray tracing algorithm is proposed to better combine with bidirectional ray tracing. Furthermore, correct integration between the lens model and bidirectional ray tracing is also analyzed. The rendering results demonstrate a variety of realistic bokeh effects caused by the aberrations.