Preprint B37/2010
Content-Based Projections for Panoramic Images and Videos
Leonardo Sacht
Keywords: Viewing sphere | panoramic images | panoramic videos.
Common cameras usually capture a very narrow field of view (FOV), around ninety degrees. The reason for this fact is that when the field of view becomes wider, the projection that these cameras use starts introducing unnatural and nontrivial distortions. This thesis studies these distortions in order to obtain panoramic images, i.e., images of wide fields of view. After modeling the FOV as a unit sphere, the problem becomes finding a projection from a subset of the unit sphere to the image plane, with desirable properties. We provide an in-depth discussion of Carroll et. al, where preservation of straight lines and object shapes are stated as the main desirable properties and an optimization solution is proposed. Next, we show panoramic images obtained by this method and conclude that it works well in a variety of scenes. This thesis also provides a novel study about panoramic videos, i.e., videos where each frame is constructed from a wide FOV. We introduce a mathematical model for this problem, discuss desirable temporal coherence properties, formulate equations that represent this properties, propose an optimization solution for a particular case and point future directions.