A focus measure for light field rendering

Light field rendering is a fundamental method for synthesizing free-viewpoint images from a set of multiviewpoint images. In the simplest case, the scene structure is approximated by a simple plane: a focal plane. This approximation leads to focus-like effects on synthetic images where the focused depth is determined by the focal plane. A serious problem is that the range of the focused depth is too small in most practical cases. In this paper, we propose a focus measure that is specialized for synthetic images by light field rendering. When a set of differently-focused images is generated at a given viewpoint, the proposed focus measure enables us to obtain a depth map and an all in-focus image. Our approach has some remarkable differences from other related techniques, such as depth-from-stereo and depth-from-focus methods. Experimental results show that the proposed method effectively enhances PSNR of the final synthetic images.