When you’re wandering through a maze of airport hallways and afraid you’ll miss your flight, your GPS can’t help you. But NAVVIS, an indoor positioning system that operates through a cellphone app, could be just the ticket. The new navigation system, based on visual information and realistic 3-D images, is designed to help visitors orient themselves in vast and complex buildings such as malls, airports, hospitals and university structures. NAVVIS could be suitable for use in all places beyond the reach of satellite navigation because wireless networks can also be used for approximate positioning, say its developers at Technical University Munich. They developed the location recognition system by taking photos in a building on campus and mapping prominent “landmarks” such as staircases. The NAVVIS system for indoor navigation makes use of realistic 3-D images to guide users through vast and complex buildings where a GPS signal is unavailable. Courtesy of G. Schroth/Technical University Munich. “With multiple floors and winding corridors, the main campus is something of a maze after several decades of expansion. This makes it an ideal testing ground for NAVVIS,” said Georg Schroth, who is heading up the project at the university’s Institute for Media Technology. To map buildings, they use a trolley that carries two laser scanners, single-lens reflex cameras and a 360° camera. When the trolley passes along a corridor, the two lasers scan the dimensions horizontally and vertically and create a virtual map using 3-D point clouds. The researchers then use software to lay the photos over the pixels, which produces a realistic 3-D view. A lost visitor who has the designated smartphone app could just snap a photo of his location and let the program do the rest: compare the photo with the images stored in its database and work out the exact position (down to the nearest meter) and even the direction in which the user is facing. App arrows can then point out the way in a 3-D view. NAVVIS has the built-in capacity to stay current as buildings change through construction, renovation and expansion. “The system doesn’t just position the user, it also utilizes the user’s photos to record changes in the interior and overwrite obsolete data,” Schroth said. The technology has other possible applications. It could provide virtual tours on a computer or smartphone, and even add to the experience in a museum. “The software can also be used for augmented reality applications if you add on special programs,” said Schroth’s colleague Robert Huitl. “So, for instance, visitors to the Louvre would not only be able to locate the Mona Lisa, but also view information about the painting or find directions to other works by da Vinci.” The researchers presented the NAVVIS system at the IEEE International Conference on Image Processing (ICIP 2012) in Orlando, Fla.