Earlier this week Nokia released an update to City Lens, its augmented reality app for Lumia smartphones. City Lens is built on Nokia’s LiveSight mapping API, which overlays the Lumia camera display with information about what's around you-- or in some cases, less. For example, the updated City Lens app provides a line of sight filter that cuts down on the number of results. Windows Phone Central has a pretty good summary of the improvements and there’s also a new video from Nokia that shows them in action. You can download the update from Nokia Beta Labs.
These new features could be very useful.