Digital refocusing for sparsely sampled light fields results in aliasing effect. For realistic quality, previous works performed anti-aliasing by applying time-consuming view interpolation for a heuristic number of novel views. In this paper, we study this problem by first performing a spectral analysis to give an analytical rule for the novel view number, which saves 34% of views compared to the intuitional choice.
Then we propose a fast refocusing algorithm using a view interpolation method which is about 30x faster than VSRS-1D-Fast. Experimental results show the effectiveness of our approach in terms of speed and quality. For showing realistic refocusing, a light-field wafer-level-optics array is implemented, and its refocused images are compared to pictures captured by a real camera.