Perception in Submarines

ICE Lab

Swedish Institute of Computer Science

Project description

The project is aimed at designing and implementing an installation that illustrates the way that a submerged submarine uses sound to gather information about its surroundings. A submarine under water is more or less blind and relies heavily on its sonars to detect other vessels. Although the periscope can be used to spot surface vessels, its range is limited (a couple of miles) and its use also increases the risk of the submarine being detected. Sonars on the other hand can pick up sounds from objects hundreds of miles away. To make this point clear to the visitors, the installation is based heavily on sound, using a soundscape consisting of authentic underwater recordings of a range of different types of vessels.

The project is a collaboration between Swedish Institue of Computer Science and Statens Maritima Museer in Sweden. The installation is part of the on-going exhibition Ubåtsvapnet 100 år which has been on display at Teknikens och Sjöfartens hus in Malmö, at Göteborgs Maritima Center (GMC) in Gothenburg, and during august 2004 in Stockholm. It is now a permanent part of the exhibitions at Marinmuseum in Karlskrona.

Implementation

The installation room is intended to represent a submarine, submerged somewhere in the Baltic sea. A nautical chart displayed on a plasma screen in the room shows the position where the submarine is located. The physical setup of the installation has been slightly altered for each of the three museums visited so far to make best use of the available space. However, the content and user experience have remained more or less the same. The basic idea has been to create a somewhat cramped space reminding visitors of the restricted space onboard a submarine. In the open hall of ”Teknikens och Sjöfartens hus”, Malmö, this meant having custom made walls and roof. In Malmö the space also allowed for two back projection screens, one on each side of the room, showing a looped recording of the forward and aft view of the control room of a Swedish submarine. In Gothenburg at GMC (a floating ship museum) the exhibition was built on the lower deck of a lighthouse boat, which added a lot to the atmosphere but also created a few problems for the setup.

    

The large-scale visual experience of the exhibition is driven by four wall mounted 40-inch Pioneer plasma displays, one on each wall. In the room are also two “hands-on” interactive stations. The first is an almost horizontal 21-inch touch screen display containing an interactive chart covering a part of the Baltic sea south of Stockholm including the north tip of Gotland.
The second interactive station is a digital periscope. The periscope presents a graphical view of the ocean surface at the position of the submarine, and can be rotated to look for ships in all directions. The periscope also provides zoom and tilt-angle controllers much like on an actual submarine. Ships that are fairly close to the submarine (within a couple of miles) will be visible as 3D objects moving slowly through the oceans waves.
Two of the plasma displays mirror what is seen in the periscope and in the nautical chart podium to allow groups of people to experience what’s on display. The remaining two plasma displays shows an underwater scene of the submarine with its sonar sensors and the sound environment it is in. Incoming sound waves are displayed as color-coded circles approaching the submarine. During a user triggered sound analysis these displays will also show frequency spectrum, sonar operator video and eventually the identified vessel

     

An important part of the installation is the computer controlled 8-channel sound system responsible for rendering the soundscape. The eight loudspeakers in the system are evenly spread out around the room making it possible to simulate sounds coming from all directions.

Intended user experience

The installation is intended to give the visitors an understanding of the importance of sound for a submarine to detect vessels in its vicinity but also far away. Via the eight channel sound system, the visitors are presented with a cacophony of sounds coming from all directions, representing a multitude of objects (vessels, animals, etc) surrounding the submarine. Via the touch sensitive nautical chart, visitors are able to select symbols representing these sound-emitting objects. When such a symbol is selected, all other sounds will fade away and the selected sound will be played in isolation. During this time the visitors are able to experience the individual characteristics of this sound, be it a seal, a small boat with an outboard motor, or a large tanker. By selecting different symbols (and thus sounds) the visitors are able to discover that different types of vessels (animals) produce quite different sounds. When a selected sound has been played for a short while, all object sounds will start again, making the previously selected sound indistinguishable. The selection of individual sounds is intended to illustrate the way that a submarine sonar operator works. By isolating and analysing the sounds one by one, indistinguishable sounds become distinguishable and thus hopefully identifiable.

 

 

Although the installation has its focus on why sounds are so important to submarines, we also wish to point out that the sounds that are mostly interesting are the ones that are caused by vessels of various kinds. To make this point clear the installation includes a digital periscope where the visitors are able to see the ships that are the sources of the sounds heard in the speaker system. By looking at a particular ship in the periscope and selecting the corresponding symbol on the nautical chart, a visitor is thus able to see the ship and at the same time hear the sound that it emits under water.

During the visit a visitor will encounter tools like BTR (Bearing Time Recorder) and LOFARgram (“waterfall” frequency spectrum diagram) which are used onboard modern day submarines.

Videos

 Perception in Submarines project video: Clip from Marinmuseum in Karlskrona 2004-01-15:
 Clip from GMC in Gothenburg (during installation setup):
 Early concept video of a view through the periscope:
Photos
Papers
Links

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