I thought of this years ago. My original purpose was to provide variable camoflage for military vehicles. My idea was actually inspired by the movie "Predator." I wanted to cover the vehicle with LCD screens and have cameras that would point at the existing background. So for example, the screen on the left side of the vehicle would get its image from a camera on the right side of the vehicle. So a person looking at the left side would see an image of the background behind the vehicle. Of course, the proportions wouldn't match unless the viewer was standing at exactly the right distance from the vehicle, and the image wouldn't line up unless he was viewing from the perfect angle. Still, it should be a better camoflage than what they use now.

It occurred to me that a civilian could use it in other ways. You could have video footage of whatever you want showing on your car. The dishonest could use it to fool the police. The police are chasing a red car. The car turns a corner. When the cops turn the corner, they will probably ignore the green car that just pulled off to the side.

If you only want to change color, there may be easier and cheaper ways to do it. Limited color change could be accomplished by using a product that is currently available that darkens windows on demand. I don't know what its called. It's a coating that is normally clear, but when an electic charge is applied to it, it turns black. I don't remember how it works, but it probably uses polarization. I don't know if it could make different colors, but at least it could lighten or darken the color of the car. I have another idea for producing color changing surfaces that actually works in a fashion similar to the way octopus and cuttlefish change color, but it's a bit hard to explain, so I should probably do it in its own page.

The technology would be liquid crystals, very similar to that on an LCD panel.