Light field upsampling by joint bilateral filtering on epipolar plane images

Due to the trade-off between spatial and angular resolution, the effective spatial resolution of a light field image is usually less than one percent of the number of pixels on the photo sensor. In this paper, we propose a prototype algorithm to upsample a light field image. Because the boundary edges of 3D objects would result in lines on epipolar plane images (EPIs), the main idea of our method is to preserve these line structures while upsampling so that the image enlargement can still have sharp boundary edges. The kernel of the proposed algorithm is an iterative joint-bilateral filtering process. Experiments show that the upsampled image derived by our method is still refocusable and has better visual quality than those derived by other methods. Finally, the main contribution of this method is that it decomposes a 4D light field space L(u, v, s, t) upsampling problem into a series of 1D, parameter-free upsampling subproblems that can be solved fast in u-s and v-t EPI domains.