Estimating the camera direction of a geotagged image using reference images

Millions of smart phones and GPS-equipped digital cameras sold each year, as well as photo-sharing websites such as Picasa and Panoramio have enabled personal photos to be associated with geographic information. It has been shown by recent research results that the additional global positioning system (GPS) information helps visual recognition for geotagged photos by providing valuable location context. However, the current GPS data only identifies the camera location, leaving the camera viewing direction uncertain within the possible scope of 360°. To produce more precise photo location information, i.e. the viewing direction for geotagged photos, we utilize both Google Street View and Google Earth satellite images. Our proposed system is two-pronged: (1) visual matching between a user photo and any available street views in the vicinity can determine the viewing direction, and (2) near-orthogonal view matching between a user photo taken on the ground and the overhead satellite view at the user geo-location can compute the viewing direction when only the satellite view is available. Experimental results have shown the effectiveness of the proposed framework.