Figure 1: Foreground and shadow occlusions are handled correctly with our proposed solution. The two images on the left shows the original frame in campus sequences and its corresponding augmented result. The two ones on the right shows the original frame in Asuka sequences and its corresponding result. ABSTRACTOcclusion handling in augmented reality (AR) applications is challenging in synthesizing virtual objects correctly into the real scene with respect to existing foregrounds and shadows. Furthermore, outdoor environment makes the task more difficult due to the unpredictable illumination changes. This paper proposes novel outdoor illumination constraints for resolving the foreground occlusion problem in outdoor environment. The constraints can be also integrated into a probabilistic model of multiple cues for a better segmentation of the foreground. In addition, we introduce an effective method to resolve the shadow occlusion problem by using shadow detection and recasting with a spherical vision camera. We have applied the system in our digital cultural heritage project named Virtual Asuka (VA) and verified the effectiveness of the system.

We have been developing an outdoor gallery system in Asukakyo. Asukakyo is one of the ancient capitals, which is well-known to has lots of temples, palaces and buildings. Nevertheless, most of the assets have been deteriorated after more than fourteen centuries. The outdoor gallery system introduces the virtual appearance of ancient Asukakyo to visitors at the original site with the help of Mixed Reality (MR). To reconstruct the virtual Asukakyo in the outdoor gallery system, it is necessary to handle occlusion problem in synthesizing virtual objects correctly into the real scene with respect to existing foregrounds and shadows. Furthermore, outdoor environment makes the task more difficult due to the unpredictable illumination changes. This paper proposes novel outdoor illumination constraints for resolving the foreground occlusion problem in outdoor environment for the outdoor gallery system. The constraints can be also integrated into a probabilistic model of multiple cues for a better segmentation of the foreground. In addition, we introduce an effective method to resolve the shadow occlusion problem by using shadow detection and recasting with a spherical vision camera. We have applied the method in our outdoor gallery system in Asukakyo and verified the effectiveness of the method.