AR-Based Positioning for Mobile Devices

Augmented Reality (AR) that can be considered as a form of location-based services is a technique utilizing position and orientation information and a location database of POIs to enrich video or photographs by adding on graphics or text objects. The AR technique can be used to develop Pedestrian Navigation Systems (PNSs), but high-precision positioning is needed for displaying AR objects at proper places. However, the required level of accuracy is far beyond current commercial positioning solutions, e.g., outdoor GPS and indoor RF systems. In this paper, we propose an AR-based positioning technique for AR users to position their locations. First, by utilizing a coarse positioning system, AR objects can be roughly displayed on the touch screen of a AR device. Then, AR objects can be matched with their images on the display via drag-and-drop operations by users. Thus, both the coordinates of the AR objects in the image and in the real world can be known. Based on the coordinates along with the knowledge of the camera focal length, the location at which the photograph was taken can be known. The location of the camera can be treated as the location of the user. The proposed positioning technique is very helpful in developing high-precision PNSs.