This Incredible Camera Ignores Perspective and Sees Behind Walls

Engineer, builder, and YouTube creator Shane Wighton, known for the YouTube channel Stuff Made Here, has tackled a lot of fascinating engineering questions over the years. The latest is one of the craziest yet. Can a camera see around objects?

“If cameras are so good at seeing stuff, why can’t they see around stuff?” Wighton asks. “You might think it’s impossible for the camera to see me back here,” Wighton says while hiding behind a cardboard wall, “but it’s not.”

“With the right kind of camera, in theory, you should be able to see behind walls,” he continues, setting the stage for an incredible photographic journey.

Wighton built this so-called “impossible” camera, and it is among the strangest cameras ever. It sees one pixel at a time but can create full images. It can also behave “like any lens,” including those that would be “almost impossible” to make using real glass.

Wighton’s wacky camera follows the same general principles as a pinhole camera. While these are often seen as some box with a small hole that lets light through, the idea can be applied to various shapes and objects. For example, Wighton talks about a tube. If photosensitive material was on one end of the tube, like an image sensor or film, and the tube was moved around in space, it could capture a scene like it was seen through different lenses. The more space that is covered, the wider the lens.

The bar shown here spins around a central axis. On one side is the camera, and on the other is a perfectly balanced counterweight to keep it stable while spinning at high speeds. The camera moves side to side along the bar and can also tilt.

As mentioned earlier, this new camera sees just one pixel at a time, creating a larger image by capturing many different views of a scene. To achieve this, the camera must move in three-dimensional space. Wighton created a spinning gantry, and the camera can move along the arm. Also, by precisely controlling the angle of a mirror that bounces light onto the image sensor, he can control where the camera is pointed.

Another essential piece, among many, is an encoder. This records the precise rotational movement and position of the photodetector at all times, ensuring Wighton can reconstruct a final image from all the individual pixels.

The entire video offers many more details and a lot of incredible information about how digital cameras work in general, but to the cut to the chase, creating this specialized camera was exceptionally challenging. After weeks of work and nearly 150 attempts, the spinning one-pixel camera did it — it created an image that looked right.

“Yes! Finally!” Wighton celebrates. “We took an actual picture of the wall! Who needs drugs when you have engineering? I had no idea you could be this excited about a picture of the wall. That is so good!”

The camera works!

With the camera operating as expected, it’s time for pictures that “are a little more interesting.”

Wighton says he had fun taking somewhat traditional pictures, but he built this camera to take “unusual pictures,” like photos that eliminate perspective. With a typical lens, and for that matter, the human eye, vision works in a cone. A camera doesn’t need to operate that way, though.

Since Wighton’s camera not only moves along a spinning axis but can tilt, it can show an orthographic projection. It shows three-dimensional objects within a two-dimensional space relying upon parallel projection. At a fundamental level, this enables the camera to show objects at their actual size regardless of their relative position to the camera. In Wighton’s first example, two mannequin heads at different distances appear the same size in the image. It’s quite mind-bending to see.

A typical camera shows these two mannequin heads, which are about the same size, as different sizes depending on their relative position to the camera. However, Wighton’s camera can work without showing perspective at all.

There’s another perspective trip up the camera’s sleeve: reverse perspective. PetaPixel has seen this type of lens before. Last year, photographer Christopher Getschmann built a hypercentric camera that relies upon reverse perspective to hilarious results.

“I don’t know why it’s so satisfying, but you have this weird theoretical thing, and seeing it actually come out in an image is just the best thing ever,” Wighton says.

After all these fun experiments, it’s time for Wighton’s camera to achieve its primary purpose, seeing around an object.

More amazing videos like this are available on the Stuff Made Here YouTube channel.

Image credits: Screenshots from Stuff Made Here’s video, “What if we made a camera that sees in reverse?”