Heng Liu, Tao Mei, Jiebo Luo, Houqiang Li, Shipeng Li, Tao Mei, and Shipeng Li
While on the go, more and more people are using their phones to enjoy ubiquitous location-based services (LBS). One of the fundamental problems of LBS is localization. Researchers are now investigating ways to use a phone-captured image for localization as it contains more scene context information than the embedded sensors. In this paper, we present a novel approach to mobile visual localization that accurately senses geographic scene context according to the current image (typically associated with a rough GPS position). Unlike most existing visual localization methods, the proposed approach is capable of providing a complete set of more accurate parameters about the scene geo---including the actual locations of both the mobile user and perhaps more importantly the captured scene along with the viewing direction. Our approach takes advantage of advanced techniques for large-scale image retrieval and 3D model reconstruction from photos. Specifically, we first perform joint geo-visual clustering in the cloud to generate scene clusters, with each scene represented by a 3D model. The 3D scene models are then indexed using a visual vocabulary tree structure. The phone-captured image is used to retrieve the relevant scene models, then aligned with the models, and further registered to the real-world map. Our approach achieves an estimation accuracy of user location within 14 meters, viewing direction within 9 degrees, and scene location within 21 meters. Such a complete set of accurate geo-parameters can lead to various LBS applications for routing that cannot be achieved with most existing methods. In particular, we showcase three novel applications: 1) accurate self-localization, 2) collaborative localization for rendezvous routing, and 3) routing for photographing. The evaluations through user studies indicate these applications are effective for facilitating the perfect rendezvous for mobile users.
In ACM Multimedia
Publisher ACM Multimedia