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They're technically not holograms but Pepper's ghost.

https://en.wikipedia.org/wiki/Pepper%27s_ghost

Calling them a hologram is like calling a lenticular a gif.




I mean, it depends. They're not always peppers ghost. It's quite common to just use transparent projector screens, as peppers ghost doesn't handle viewing angles all that well.


A hologram is a light field captured onto a film.

These live displays are usually just some sort of optical illusion.

A real hologram shows you the actual light from the captured event as it’s the entire light field from the event. So your eyes are receiving essentially stored light.


Right there with you friend, but unfortunately that's not how language works and there's no hard line as to what is and isn't a "hologram". Yes, you can coherently capture a real light wave field directly onto photo-material - you can also generate one synthetically, quantize your light field into spatial "hogels", eliminate an axis of parallax, constrict the FOV etc, and finally replace your interference-based "hogels" with lenses and you have an integral image or lenticular, which is different physics but exactly the same imaging principles. Every one of those stages is a "hologram" to some set of people - hardcore holographers might draw the line at analog techniques, researchers will accept anything interference-based, and laypeople will slap the label on just about anything that looks cool.

Believe me - this isn't a battle worth fighting. At the end of the day, everything is an illusion. Vision is not reality.

Source: many a long year making digital holograms and trying to explain to people what it is I do.




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