Image-based relighting from a sparse set of outdoor images

We propose a novel method for relighting the image of outdoor scenes viewed from a fixed camera based on a sparse set of images of the same scene under different illumination. Unlike previous methods which require capturing images under pre-designed lighting or employing the 3D model of the target objects, our method adopts the technique of basis image which encapsulates material and geometry information of the scene into one image. We present a new method to calculate the basis images of an outdoor scene based on the sampling images captured in different time of a day, the relighting images corresponding to new sunlight incidence directions with arbitrary intensity can then be generated with these basis images. Besides, the subordinate shadow effect adhering to the sun's movement is also simulated, producing a visually plausible relighting result. Experiments demonstrate the efficiency and validity of our approach. (C) 2013 Elsevier Ltd. All rights reserved.