Illumination estimation for augmented reality based on a global illumination model

With the rapid development of 3D technology, the illumination consistency plays an important role in realistic rendering of virtual objects which are superimposed into the real scene. In this paper we proposed a new approach to estimate illumination, given the images of a scene. Our algorithm is designed from principles in optics, which is based on a global illumination model. First, we get the images of a scene and perform scene reconstruction using images. Then, a photon emission hemispherical model is built for emitting photons into the scene. The photons are traced, meanwhile the result is stored in multiple photon maps. Finally, the estimated illumination is obtained by estimating the photon radiance value in the photon emission hemispherical model. Experiments on our newly collected real scene databases and virtual scene databases show the accuracy of our method subjectively and objectively. By comparing with related work, it is found that more accurate results can be obtained using the global illumination inversely.