A group of researchers at Keio University in Japan have developed a prototype of an invisibility cloak (of sorts) for your car. However, instead of making your car invisible to others (which is probably a really, really bad idea), it makes your car invisible to you (on the inside).

You probably have seen rear-view displays mounted in-car dashboards, which enable the driver to see what is behind the car. However, the driver must stare forwards at the rear-view camera instead of backwards, where they are driving. And there isn’t an equivalent for the sides of the car.

To solve this conundrum, the team of researchers decided to use projection mapping to make the inside of the car invisible. They have a projector mounted to the center console of the car which can illuminate the backseat or sides of the car. The projector simply displays the video feed from a camera mounted on the exterior of the car.

As we projection mappists are aware, projection in bright daylight is a tricky thing and requires expensive, bulky projectors. To solve this issue, the team covered the inside of the car in a retro-reflective material. Retro-reflective materials are special because they reflect incoming light in the exact direction that it comes in. This means that you can use a projector to create a display even in bright sunlight. (Similar to the Kickstarter CastAR).

Another issue with projection mapping is to get the correct perspective (anamorphosis) requires a complex 3d model of the display surface and some tricky math. So the team used a half silvered mirror to effectively position the projector at the viewer’s location.

Check out the full post on IEEE Spectrum.

Work done by Susumu Tachi, Masahiko Inami & Yuji Uema