When I was a kid, there was a periscope you could make out of a cardboard tube and two small hand mirrors to see around corners. Now there’s a video camera system that can do the same.
Camera Can See Around Corners and Femtosecond Camera Sees Around Corners articles tell that Scientists at the Massachusetts Institute of Technology in Cambridge have created a camera that is able to record images of objects hidden behind walls. The video system, called Cornar, was created by researchers at the Massachusetts Institute of Technology’s Media Lab. It can look beyond the line of sight, as well as peer around corners.
Conar is based on a ultra-fast camera sensor and a femtosecond laser. Conar works by firing a pulse of laser light at a wall on the far side of the hidden scene, and record the time at which the scattered light reaches a camera. Bursts of light generated by the laser reflect off of multiple surfaces and reconstruct a 3D image. The camera captures this time-of-flight information and uses it to reconstruct an image of the hidden object (abstract). Photons bounce off the wall onto the hidden object and back to the wall, scattering each time, before a small fraction eventually reaches the camera, each at a slightly different time.
How to see around corners article points to this nice video of Conar operation.
It seems that scattering is not the only way to bend light around corner. Light normally travels in straight lines, but physicists have known for several years that superimposing a pattern on a laser beam can make it bend. Self-bending light boomerangs could help surgeons article tells that self-beaming light beams are capable of turning a corner like a boomerang. They are darting around an optics laboratory in France. The team have bent beams just a few micrometres across by up to 60 degrees, using a device known as a spatial light modulator. The beam pattern is designed so that the individual light rays that make up the beam interfere with each other in a way that makes the beam curve. Dudley’s team has already used these bendy lasers to carve glass into curved shapes.
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Hunter Aponta says:
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Tomi Engdahl says:
Hyper-sensitive laser camera sees around corners in real time
http://www.extremetech.com/extreme/219282-hyper-sensitive-camera-can-see-around-corners-in-real-time
You never know what’s around the corner — unless you happen to have a super-advanced camera designed by researchers at Heriot-Watt University in Edinburgh, Scotland. This device has been designed to take extremely sensitive photographs that can detect the minute reflected lights from objects not in its field of vision. The result is a camera that sees around corners, and it works in real time.
The single-photon avalanche diode (SPAD) camera relies upon a type of echo mapping. You can think of it a little like radar, but with light. This part isn’t anything new — other projects have managed to do similar things. However, this camera is so sensitive that it can capture a photo every second. Therefore, you can watch an object move with the SPAD camera even when it’s technically out of sight.
Tomi Engdahl says:
Seeing Around Corners with Frickin’ Lasers
http://hackaday.com/2015/12/14/seeing-around-corners-with-frickin-lasers/
Researchers at the University of Edinburgh and Heriot-Watt University have created a sensor that can see around corners using lasers, high speed cameras, and some intense data processing. They can essentially turn a laser light source into a virtual mirror to look through.
Here’s how this amazing new camera can see around corners
Spy game is strong.
http://www.sciencealert.com/here-s-how-this-amazing-new-camera-can-see-around-corners
Tomi Engdahl says:
Smartphone Cameras Peek Around Corners by Analyzing Patterns of Light
https://spectrum.ieee.org/tech-talk/consumer-electronics/audiovideo/mit-shows-how-smartphones-could-peek-around-corners
Magically seeing around corners to spot moving people or objects may not rank first in most people’s superhero daydreams. But MIT researchers have shown how they could someday bestow that superpower upon anyone with a smartphone.
Their secret to peeking around corners is detecting slight differences in light patterns reflected from moving objects or people. Those reflected light patterns form subtle variations in the shadowy area near the base of each corner. MIT’s Computer Science and Artificial Intelligence Lab (CSAIL) created simple software that can detect fuzzy pattern variations in the pixels of a 2-D video—taken by a basic consumer camera or even a smartphone camera—and reconstruct the speed and trajectory of moving objects by stitching together multiple, distinct 1-D images.
Tomi Engdahl says:
Stanford researchers develop technique to see objects hidden around corners
https://news.stanford.edu/2018/03/05/technique-can-see-objects-hidden-around-corners/
Someday your self-driving car could react to hazards before you even see them, thanks to a laser-based imaging technology being developed by Stanford researchers that can peek around corners.
Tomi Engdahl says:
https://hackaday.com/2019/08/25/take-pictures-around-a-corner/
Tomi Engdahl says:
https://spectrum.ieee.org/cars-that-think/sensors/automotive-sensors/seeing-around-corner-lasers-speckle
Tomi Engdahl says:
A Single Laser Fired Through a Keyhole Can Expose Everything Inside a Room
If you’re worried about privacy, it might be time to cover up your front door’s peephole.
https://gizmodo.com/a-single-laser-fired-through-a-keyhole-can-expose-every-1847638281
Tomi Engdahl says:
The Wall Tells All
This device can detect people, and what they are doing, by making subtle observations on a blank wall
https://www.hackster.io/news/the-wall-tells-all-b0ae6c4dee7b
Tomi Engdahl says:
https://www.iflscience.com/technology/new-holographic-camera-can-see-around-corners-or-inside-your-skull/
Tomi Engdahl says:
https://hackaday.com/2021/12/21/laser-sees-through-keyhole/
Those guys at Stanford must be watching a lot of James Bond movies. Their latest invention is a laser that can image an entire room through a keyhole. We imagine that will show up in a number of spy movies real soon now.
Keyhole Imaging | IEEE TCI 2021
https://www.computationalimaging.org/publications/keyhole-imaging/
Non-line-of-sight (NLOS) imaging and tracking is an emerging technology that allows the shape or position of objects around corners or behind diffusers to be recovered from transient, time-of-flight measurements. However, existing NLOS approaches require the imaging system to scan a large area on a visible surface, where the indirect light paths of hidden objects are sampled. In many applications, such as robotic vision or autonomous driving, optical access to a large scanning area may not be available, which severely limits the practicality of existing NLOS techniques. Here, we propose a new approach, dubbed keyhole imaging, that captures a sequence of transient measurements along a single optical path, for example, through a keyhole. Assuming that the hidden object of interest moves during the acquisition time, we effectively capture a series of time-resolved projections of the object’s shape from unknown viewpoints. We derive inverse methods based on expectation-maximization to recover the object’s shape and location using these measurements. Then, with the help of long exposure times and retroreflective tape, we demonstrate successful experimental results with a prototype keyhole imaging system.
Tomi Engdahl says:
LETTING ROBOCARS SEE AROUND CORNERS
Using several bands of radar at once can give cars a kind of second sight
https://spectrum.ieee.org/car-radar
Tomi Engdahl says:
Quantum Holograms Don’t Even Need to “See” Their Subject New holographic technique could be used for indirect medical imaging and more
https://spectrum.ieee.org/quantum-holography-using-undetected-light?share_id=6896972
Tomi Engdahl says:
Researchers have shown that the computational imaging technique known as ghost imaging can be combined with human vision to image an object that can’t directly be seen by the person.
Researchers perform non-line-of-sight ghost imaging with human vision
https://techxplore.com/news/2022-06-non-line-of-sight-ghost-imaging-human-vision.html
Researchers have shown that the computational imaging technique known as ghost imaging can be combined with human vision to image an object that can’t directly be seen by the person. The new work represents a step toward combining human intelligence with artificial intelligence.
“This is one of the first times that computational imaging has been performed by using the human visual system in a neurofeedback loop that adjusts the imaging process in real time,” said Faccio. “Although we could have used a standard detector in place of the human brain to detect the diffuse signals from the wall, we wanted to explore methods that might one day be used to augment human capabilities.”
The experimental setup used a projector to create light patterns on a cardboard cut-out that acted as the object being imaged. The transmitted light diffused onto a secondary white wall hidden from view by a dark wall. Thus, the observer could only see diffuse light reflected from the secondary white wall. Each light pattern was flickered at 6 Hz for two seconds, creating a signal in the observer’s visual cortex that was detected with a single-electrode electroencephalography (EEG) headset.