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Trish
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No

Projectors

Let's start with a hypothetical situation: There is a cylinder. It has cameras on all sides to project the image it takes up to the other side. So if you watch at the item face on, it blends into the surroundings.

Now, make a step to the side. The projection to that face does not line up with the image behind it and is immediately obvious because it can only project to its surface the light that would fall through its center axis - but you'd need the light that does not pass through that axis.

Lenses

Using lenses, you can't achieve total success either: to be invisible by light being refracted around you, the lens can at best cover half the body - any more and it will show the lenses on the backside. Then those lenses also only work when looked orthogonally onto them - again, if you look at the thing from the wrong angle, you see it. Then, it very much distorts the background, and any natural background makes that very visible. And last but not least: your object needs to be a certain distance from the lens. Which is quite large: to hide a 10 cm car model, you need about 10 cm from the car to the lens screen. To hide a 50 cm wide human, the shield needs to be about as far from the body.

This makes Lenses not an option for an invisibility cloak, and as a screen, they are totally obvious about their presence. They might hide what is there, but not that something is there - a huge fail.

Extra: different wavelengths are refracted differently. These lenses don't obscure the object to an infrared or UV camera in the same way.

No

Let's start with a hypothetical situation: There is a cylinder. It has cameras on all sides to project the image it takes up to the other side. So if you watch at the item face on, it blends into the surroundings.

Now, make a step to the side. The projection to that face does not line up with the image behind it and is immediately obvious because it can only project to its surface the light that would fall through its center axis - but you'd need the light that does not pass through that axis.

No

Projectors

Let's start with a hypothetical situation: There is a cylinder. It has cameras on all sides to project the image it takes up to the other side. So if you watch at the item face on, it blends into the surroundings.

Now, make a step to the side. The projection to that face does not line up with the image behind it and is immediately obvious because it can only project to its surface the light that would fall through its center axis - but you'd need the light that does not pass through that axis.

Lenses

Using lenses, you can't achieve total success either: to be invisible by light being refracted around you, the lens can at best cover half the body - any more and it will show the lenses on the backside. Then those lenses also only work when looked orthogonally onto them - again, if you look at the thing from the wrong angle, you see it. Then, it very much distorts the background, and any natural background makes that very visible. And last but not least: your object needs to be a certain distance from the lens. Which is quite large: to hide a 10 cm car model, you need about 10 cm from the car to the lens screen. To hide a 50 cm wide human, the shield needs to be about as far from the body.

This makes Lenses not an option for an invisibility cloak, and as a screen, they are totally obvious about their presence. They might hide what is there, but not that something is there - a huge fail.

Extra: different wavelengths are refracted differently. These lenses don't obscure the object to an infrared or UV camera in the same way.

Source Link
Trish
  • 17.2k
  • 1
  • 43
  • 74

No

Let's start with a hypothetical situation: There is a cylinder. It has cameras on all sides to project the image it takes up to the other side. So if you watch at the item face on, it blends into the surroundings.

Now, make a step to the side. The projection to that face does not line up with the image behind it and is immediately obvious because it can only project to its surface the light that would fall through its center axis - but you'd need the light that does not pass through that axis.