Modeling and Synthesis of Aperture Effects in Cameras

Abstract

In this paper we describe the capture, analysis, and synthesis of optical vignetting in conventional cameras. We analyze the spatially-varying point spread function (PSF) to accurately model the vignetting for any given focus or aperture setting. In contrast to existing "flat-field" calibration procedures, we propose a simple calibration pattern consisting of a two-dimensional array of point light sources - allowing simultaneous estimation of vignetting correction tables and spatially-varying blur kernels. We demonstrate the accuracy of our model by deblurring images with focus and aperture settings not sampled during calibration. We also introduce the Bokeh Brush: a novel, post-capture method for full-resolution control of the shape of out-of-focus points. This effect is achieved by collecting a small set of images with varying basis aperture shapes. We demonstrate the effectiveness of this approach for a variety of scenes and aperture sets.