The Holographic Comparison Grid  is one of the Ghostbusters' research equipment and helps with comparing with visual aids.
Stored in Egon's lab, it was once used when the team was investigating Janine Melnitz and her mysterious changes over the years. Much like a holographic projector, the comparison grid projects multiple images. After examining images of her face, height, bone structure, and cellular structure, Egon concluded there was concrete evidence of ectoplasmic energy as the source of these changes.
- ↑ Egon Spengler (2009). The Real Ghostbusters - "Janine, You've Changed" (1990) (DVD ts. 08:07-08:09). Time Life Entertainment. Egon says: "Activating Holographic Comparison Grid, now."