4 ms·

Can we make a camera see behind walls? [video]

30 points by ACAVJW4H 2y ago

Havoc 2y ago
Vaguely related. Recently discovered that the 24ghz radar units I’ve got go through walls. Not solid brick walls though
geerlingguy 2y ago
Sadly this post will probably get buried because it's a video link, but it really deserves some front page coverage. This project involves a bunch of different disciplines, and I'm always amazed by what Shane can do in his (very expensive) mad science lab.
- huttyoop 2y ago
  I really wish HN would have a ‘video’ tag link at the top next to ‘new’, ‘show’, and ‘ask’. Over the years I’ve written various scripts and tools to only grab yt links or posts with [video] in the title from the HN api. Be nice if I could just click the link at the top rather than rebuilding each time I lose the old ones. :)
romanhn 2y ago
Amazing engineering here, but isn't this equivalent to raising your camera above the wall and then snapping a pic? This wasn't really seeing behind walls in the sense I expected.
- geerlingguy 2y ago
  The idea of a camera that can design its own lens by shifting the sensor in a large area is interesting on its own, but the 'hook' is it can "see behind things" by being so large. The title appeals to a broader audience, and technically it's true, if comparing to any typical camera or working human eyeball arrangement.
- bitshiftfaced 2y ago
  It's a bit different than that since the image perspective is as if the camera is directly in front of the wall. Normally if you take a picture from above the wall, the perspective is from the angle of the camera pointing over the shoulder of the wall.
BatFastard 2y ago
Very misleading.
FloNeu 2y ago
It’s called a window
ACAVJW4H 2y ago
This reminds me of MIT’s work on femto-photography to see around corners. They used ultrafast laser pulses to bounce light off walls, capturing the reflections from hidden objects. By analyzing the time-of-flight data, they could reconstruct 3D shapes of objects not in direct view. <https://web.media.mit.edu/~raskar/cornar/ https://web.media.mit.edu/~raskar/cornar/>
- juancn 2y ago
  Using a projector and computing the light field (i.e. single pixel, controlled light source) it is also possible to look around corners. It's probably easier to achieve than time of flight of photons.
  - xnx 2y ago
    That's exactly what I was expecting given he [original] video title.
onetokeoverthe 2y ago
tempest. 20+ years ago. can 'see' computer screens thru walls at a distance. https://yandex.com/search/?text=tempest+program+see+computer+screens https://yandex.com/search/?text=tempest+program+see+computer...
kobalsky 2y ago
The title from the video was changed to "What if we made a camera that sees in reverse?" which is more fitting since "seeing behind walls" was a bit clickbaity since the camera is mounted big arm literally peeking with a mirror. The guy made a home made camera with orthographic projection, that should been enough for the title...
pants2 2y ago
The orthographic image is the coolest thing I've seen in a while! This is some remarkable engineering. I expected the images to be much lower quality but they look great.

30 points by ACAVJW4H 2y ago

Vaguely related. Recently discovered that the 24ghz radar units I’ve got go through walls. Not solid brick walls though

Sadly this post will probably get buried because it's a video link, but it really deserves some front page coverage. This project involves a bunch of different disciplines, and I'm always amazed by what Shane can do in his (very expensive) mad science lab.

huttyoop 2y ago
I really wish HN would have a ‘video’ tag link at the top next to ‘new’, ‘show’, and ‘ask’. Over the years I’ve written various scripts and tools to only grab yt links or posts with [video] in the title from the HN api. Be nice if I could just click the link at the top rather than rebuilding each time I lose the old ones. :)

romanhn 2y ago

Amazing engineering here, but isn't this equivalent to raising your camera above the wall and then snapping a pic? This wasn't really seeing behind walls in the sense I expected.

geerlingguy 2y ago
The idea of a camera that can design its own lens by shifting the sensor in a large area is interesting on its own, but the 'hook' is it can "see behind things" by being so large. The title appeals to a broader audience, and technically it's true, if comparing to any typical camera or working human eyeball arrangement.
bitshiftfaced 2y ago
It's a bit different than that since the image perspective is as if the camera is directly in front of the wall. Normally if you take a picture from above the wall, the perspective is from the angle of the camera pointing over the shoulder of the wall.

BatFastard 2y ago

Very misleading.

FloNeu 2y ago

It’s called a window

ACAVJW4H 2y ago

This reminds me of MIT’s work on femto-photography to see around corners. They used ultrafast laser pulses to bounce light off walls, capturing the reflections from hidden objects. By analyzing the time-of-flight data, they could reconstruct 3D shapes of objects not in direct view. <https://web.media.mit.edu/~raskar/cornar/ https://web.media.mit.edu/~raskar/cornar/>

juancn 2y ago
Using a projector and computing the light field (i.e. single pixel, controlled light source) it is also possible to look around corners. It's probably easier to achieve than time of flight of photons.
- xnx 2y ago
  That's exactly what I was expecting given he [original] video title.

onetokeoverthe 2y ago

tempest. 20+ years ago. can 'see' computer screens thru walls at a distance. https://yandex.com/search/?text=tempest+program+see+computer+screens https://yandex.com/search/?text=tempest+program+see+computer...

kobalsky 2y ago

The title from the video was changed to "What if we made a camera that sees in reverse?" which is more fitting since "seeing behind walls" was a bit clickbaity since the camera is mounted big arm literally peeking with a mirror. The guy made a home made camera with orthographic projection, that should been enough for the title...

pants2 2y ago

The orthographic image is the coolest thing I've seen in a while! This is some remarkable engineering. I expected the images to be much lower quality but they look great.