Camera Ignores Perspective and Sees Behind Walls

https://petapixel.com/2024/12/09/this-incredible-camera-ignores-perspective-and-sees-behind-walls/

by PaulHoule • 2 years ago

14 12 2 years ago

dataflow2• 2 years ago

Did I misunderstand what is going on, or is this basically just saying "move the camera around to see behind the object"?

Edit: s/camera/sensor/ if that clarifies

4gotunameagain• 2 years ago

It is, with extra projection steps.

I believe it is called the "clickbait projection" in mathematics.

But yea, it is an interesting video and topic.

maury91• 2 years ago

You can visualize it easily if you think about your own vision.

If you put an hand in from of your face ( without covering your eyes ) you will be able to see behind it even if both eyes see only a part of what is behind your hand.

Now regarding the video imagine that each pixel is an eye, and they are spreaded evenly along a circle.

There are a lot of differences between this example and what he actually did, but it should be very easy to visualize ( main difference I can think of is how much amplification he needed to do so each eye is almost blind )

ozim• 2 years ago

Not exactly as he emulates different lenses.

Notice his device is always facing forward and it doesn’t turn to side to get pixel data so you would expect to get an image from what is exactly in front of the sensor. But it is not in case where he sets it when making picture “behind”.

lilyball• 2 years ago

Isn't that what the mirror is for, to change the angle of light captured?

shawa_a_a• 2 years ago

This isn’t exactly the case. The camera has an actuating mirror on the end of the rotating arm that allows it to point at arbitrary angles.

https://youtu.be/aXfTgCCsRSg (T=4:30)

The emulating different lenses part is that with this setup you can parametrically collect specific rays bouncing off the object (presumably the angle of the mirror with respect to radius), and the resulting image will be the same as you’d get from a lens with those parameters.

furyofantares• 2 years ago

Same reaction here but with a little more thought I give it more credit. The resulting image looks like you're looking at the subject head-on from a point behind the wall. It doesn't look like you're peeking over the wall at some angle.

The actual video doesn't have this headline, the clickbait comes from this article that doesn't really add anything over the video. It's clearly referencing the part of the video where says "sees around walls", but actually that is more accurate anyway compared to "sees behind walls" because it does see all around the wall. The ring lens characterization in the video is even better at not setting a weird expectation.

The video itself is wonderful regardless. I thought the ignored and reversed perspective shots were amazing.

dataflow2• 2 years ago

Thanks, I didn't have a chance to watch the video, I just read the article. I'll have to take a look at it later.

system2• 2 years ago

The title is clickbait. This has nothing to do with this project.

syvanen• 2 years ago

Yeah, would be better if this just links the video and not a website that has now original content but just describes the video.

jumperabg• 2 years ago

Totally clickbait the idea of testing out different lenses is great but in order to see behind the wall he just puts the camera higher around the wall and then makes the picture.

I was personally expecting a breakthrough or a mechanism that is smaller and doesn't go above the object in order to make a picture from the simulated lenses.

DougBTX• 2 years ago

The article doesn’t explain why this is interesting. Here’s a different way of putting it:

A classic pinhole camera is a box with a hole in it. The hole is small, so not much light gets in. We replace it with a lens that acts in effectively the same way, but lets in more light. The pinhole is inside the camera, and there is an obstacle in front of the subject, so the camera can’t see it. The fun thing here, is that this camera has a pinhole _outside_ the camera, so the pinhole can be positioned on the other side of the obstacle, and therefore take a picture of the subject.

Camera Ignores Perspective and Sees Behind Walls

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