The U.S. Navy is installing a 360 degree video camera in the periscopes
of its subs. Currently, the navy uses a 12 megapixel day camera, and a lower
rez (640x480 pixel) night vision camera. Both of these display the images on
various flat panel displays inside the ship, including a very large one in the
CIC (Combat Information Center). The 360 degree camera will record all that it
sees, so that the crew can later review what was there. This will enable the
sub to keep its periscope above water for a minimal amount of time when in
hostile territory, or provide a record of what was happening in case there's an
accident as the sub is surfacing. The technology (from RemoteReality) is
already used in commercial products.
Over the last decade, the navy has been replacing traditional optical
periscopes with electronic ones, using digital cameras.