NEW YORK (AdAge.com) -- Among the most interesting new technologies that promise to dramatically alter the outdoor video-advertising business is real-time facial recognition systems. With a scanning device installed on every video screen, they send a constant stream of data back to a central computer. Each unit can "read" passing faces to determine which are actually looking at the ads on that specific screen. They can also estimate the age, sex and level of interest of onlookers. And the systems can provide second-by-second data reports, something like outdoor advertising's version of TV's commercial ratings.