Emergency holographic program
An emergency holographic program was a hologram designed to fill a particular function aboard a starship or space station in the event of an emergency. These programs were not meant to be used continuously and originally required a crewmember to activate them, though later programs were able to active themselves if the computer detected an emergency. (Star Trek: Voyager; Star Trek: Picard)
These holographic programs were introduced by Doctor Lewis Zimmerman.

Doctor Lewis Zimmerman, considered the father of modern holography.

USS Voyager's EMH, The Doctor.

Mister Hospitality, La Sirena's EHH.
Emergency holographic programs |
|---|