Handling occluders in transitions from panoramic images: A perceptual study

Panoramic images are very effective at conveying a visual sense of presence at very low cost and great ease of authoring. They are, however, limited in the navigation options they offer, unlike 3D representations. It is therefore desirable to provide pleasing transitions from one panorama to another, or from a panorama to a 3D model. We focus on motions where the viewers move toward an area of interest, and on the problem of dealing with occluders in their path. We discuss existing transition approaches, with emphasis on the additional information they require and on the constraints they place on the authoring process. We propose a compromise approach based on faking the parallax effect with occluder mattes. We conduct a user study to determine whether additional information does in fact increase the visual appeal of transitions. We observe that the creation of occluder mattes alone is only justified if the fake parallax effect can be synchronized with the camera motion (but not necessarily consistent with it), and if viewpoint discrepancies at occlusion boundaries are small. The faster the transition, the less perceptual value there is in creating mattes. Information on view alignment is always useful, as a dissolve effect is always preferred to fading to black and back.