Sub-space emission scan 247
A sub-space emission scan was a report made by computers aboard a starship, where subspace field subatomic particle levels are read out on a viewscreen, based on information from the starship's sensors.
One such emission scan displayed continuously on several bridge monitors aboard USS Voyager and other starships like it. (Star Trek: Voyager video playback set artwork)
A sub-space emission scan was used by the USS Voyager to detect a micro-wormhole in 2371. (VOY: "Eye of the Needle")
The "sub-space emission scan 247" screen was a computer graphic artwork played continuously on some monitors on the set of Star Trek: Voyager, aboard Voyager and probably many other starships of the same era. The screen is reproduced legibly in Stephen Edward Poe's A Vision of the Future - Star Trek: Voyager companion book.