In Ghost in the Shell, Scarlett Johansson’s Major owes much of her deadly skill to her incredible powers of stealth. Thanks to her iconic thermoptic suit, she can slip in and out of her environment as if she were invisible. And if she wanted to slip quietly out of her sci-fi trappings and into the real world, she’d have no problem doing it: A team of Japanese scientists, taking inspiration from such fictional suits, have been working on making the thermoptic suit a reality.
Susumu Tachi, Professor Emeritus at the University of Tokyo, pioneered the use of “retro-reflective projection” technology (RPT), which led him to design fabrics that act, essentially, like Major’s suit. Remember that thermoptic technology, as it’s described in the series, doesn’t quite give the user invisibility — that is, it doesn’t make them vanish entirely. Rather, it allows them to camouflage themselves in their surroundings. This is what RPT, a form of “active camouflage” Tachi first described in a paper in 2003, achieves through the use of special fabrics and well-angled cameras. Here’s an image of a camouflage coat prototype, taken in 2012:
It doesn’t blend seamlessly, but neither does Major’s suit. In the Ghost In The Shell series, the thermoptic suit blends in with its surroundings and is near-invisible with the naked eye, but it can’t withstand sudden physical impacts and is pretty noticeable up close. The special fabric that Tachi’s retro-reflective projection technology depends on is covered in glass beads only 50 microns wide and is, likewise, not invisible but is reflective, which is even more important for Tachi’s work. The fabric is a screen onto which digital images of the background environment can be projected. As the background images are reflected back at the source — and the viewer — the object beneath the cloak “disappears.”
In the real world, just as in science fiction, active camouflage technology like Tachi’s hasn’t escaped the notice of the military and related organizations. More recent, similar work by researchers at the University of California San Diego, for example, has produced Teflon-based “fluid mirrors” for drone camouflage. Likewise, University of California-Berkeley scientists have suggested using sheets of polarized gold nanoantennae to camouflage large objects, like bomber planes.
The ability to sneak around undetected, of course, raises a lot of concerns about privacy and ethics. In the real world, the laws surrounding the use of such technology still need to be hammered out. When real-life lawmakers are inevitably forced to confront these issues, they should take their cues from their counterparts in Ghost In The Shell: In the series, using thermoptic suits without a warrant is “heavily restricted,” reserved only for Major and her elite crew of counter-terrorists.