New Spinning Drone Hides In Plain Sight (northwestern.edu) 56
To design invisible drones, researchers have tried camouflage, transparent materials and light-bending optical systems. But engineers at Northwestern University used "motion blur," which an announcement from the school notes is the effect that makes fast-spinning fans seem to disappear.
"The drone spins up to 25 times per second, which is too fast for the human eye to see clearly. While it isn't completely invisible, it morphs into a ghostly smudge that seamlessly blends into the background... " To design the drone, the Northwestern team first used a computational model to generate roughly 20,000 drone configurations capable of stable flight. Then, they used artificial intelligence (AI) and optimization algorithms to repeatedly rearrange the drones' major components, including a motor, propeller, circuit board, counterweight and batteries. After sifting through many different configurations, the algorithms determined the ideal placement of the drone's components to minimize its visibility from virtually every viewing angle while allowing for stable flight.
After selecting promising candidates, the engineers simulated each drone spinning in flight and overlaid those images a hundred real-world backgrounds. Then, they used a perception model that approximates human vision to determine how noticeable each design appeared. Designs that blended into their surroundings received lower visibility scores. The team selected the 500 lowest-scoring designs and applied the optimization algorithm, which repeatedly adjusted the positions of components to further minimize those scores. "The design process was fully automated," [said Northwestern's associate CS professor Michael Rubenstein, who led the work]. "Then, when we were confident that a drone met all our criteria, we built it."
They've named the drone "Phantom Twist"," and plan to design future iterations with more transparent materials or quieter propulsion to make it even less noticeable.
The Northwestern team presented the work on July 16 at Robotics: Science and Systems 2026 in Sydney, Australia...
Thanks to long-time Slashdot reader fahrbot-bot for sharing the news.
"The drone spins up to 25 times per second, which is too fast for the human eye to see clearly. While it isn't completely invisible, it morphs into a ghostly smudge that seamlessly blends into the background... " To design the drone, the Northwestern team first used a computational model to generate roughly 20,000 drone configurations capable of stable flight. Then, they used artificial intelligence (AI) and optimization algorithms to repeatedly rearrange the drones' major components, including a motor, propeller, circuit board, counterweight and batteries. After sifting through many different configurations, the algorithms determined the ideal placement of the drone's components to minimize its visibility from virtually every viewing angle while allowing for stable flight.
After selecting promising candidates, the engineers simulated each drone spinning in flight and overlaid those images a hundred real-world backgrounds. Then, they used a perception model that approximates human vision to determine how noticeable each design appeared. Designs that blended into their surroundings received lower visibility scores. The team selected the 500 lowest-scoring designs and applied the optimization algorithm, which repeatedly adjusted the positions of components to further minimize those scores. "The design process was fully automated," [said Northwestern's associate CS professor Michael Rubenstein, who led the work]. "Then, when we were confident that a drone met all our criteria, we built it."
They've named the drone "Phantom Twist"," and plan to design future iterations with more transparent materials or quieter propulsion to make it even less noticeable.
The Northwestern team presented the work on July 16 at Robotics: Science and Systems 2026 in Sydney, Australia...
Thanks to long-time Slashdot reader fahrbot-bot for sharing the news.
25 x per sec (Score:5, Interesting)
how does it see out?
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O you again.
He's just not into you.
Let it go, Let it go...
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I imagine it could see 360 if equipped with cameras. I don't even think it would be a super hard problem to solve.
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Make sure your camera is capable of 25 frames per second, and look at every 25th frame. Pretty trivial, actually, and with a large memory card, you have 360 video as good as most movies.
Re: 25 x per sec (Score:4, Interesting)
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" of 25 frames per second, and look at every 25th frame."
Why? You can watch every second and STILL only see 1 direction.
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Not really. You capture the other 24 and lay them out in a curved simulated wrap-around view - with the extreme left and right being the same snapshot. You can see 360 that way - even behind you - as well as seeing "forward".
Marry that with a small explosive payload and you're in business.
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Designing a drone using this technique that could do anything useful would appear to be a considerable challenge. You would have to add the equipment to do whatever you wanted without unbalancing the drone and also make it work despite the spin. Probably not impossible, but would it be worth the effort?
If it can be made large enough to carry explosive charges it would be useful on the battlefield. You might hear it but have a hard time spottig it until it goes boom.
Re:25 x per sec (Score:4, Insightful)
The challenge is that it's small and wirey. It's that by design because going larger would make it easily visible.
Besides, regular drones are hard enough to see, and even harder to hit, at the speeds they travel with explosives.
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the prototype seems balanced with a simple makeshift ballast https://news.northwestern.edu/... [northwestern.edu] i guess to distribute the mass in a way to preserve the visual effect of spin. clever! i guess suspending a static part from a gyro in the center of spin shouldn't be too difficult ... e.g. a ccd sensor could be very small, still hard to detect. the thing is quite noisy, though ...
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Sure. Not seeing something is very useful.
I imagine that this would have two use cases. Firstly the one where it is observing, and this could use all sorts of tricks with timing the observations to match the speed of rotation. Second, there is just having it get to where it needs to be with minimum observation - then, execute when discovery is no longer a problem. (Potentially, slowing down from 25 Hz to zero might give a discoverability window)
Conventional radar should probably pick this up as well, no? As
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The application for this seems to be things like sports broadcasting. The drone, with a built in camera, is your equipment.
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Fans don't like big camera drones flying around in front of the action they paid ridiculous prices to sort of see. Stadiums are also both big and loud.
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The summary says it looks something like a spinning fan, which makes sense. How visible it is would depend on the fraction of the view that is occluded: wider or more "fan blades" would be more visible.
How visible it is to cameras would absolutely depend on the shutter speed they're using. You'd have to avoid shutter speeds that sync too closely with the drones' rotation, or you could further enhance the effect in a camera with a fast shutter speed and an algorithm that paints in occluded areas with informa
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how does it see out?
Perhaps it's a bit like the Star Trek cloaking device (which while in use prevents the use of shields or weapons). If the drone wants to see, it needs to drop its cloaking device.
Re: 25 x per sec (Score:5, Insightful)
Re: 25 x per sec (Score:4, Informative)
Frame rate is the wrong metric. The question is what *shutter angle* is used. A typical cinema camera a 25 fps has a shutter angle of 180degrees. What this means in practice is that 25 times a second the shutter will be open and exposing for 1/50th of a second. That's enough for the drone to do half a rotation very much turning into a blurry mess on every frame. The shutter angle determines the motion blur.
It's that frame exposure time that determines motion blur, not the frame rate alone. If you want to in a video feed see the drone you don't need to synchronise the frame rate (though doing so would effectively make it not appear to rotate, though still appear to blue depending on the individual frame exposure time determined by the shutter angle), you need to dramatically reduce the shutter angle.
If you ever wonder why war movies look crips and jerky even though they are at the same 24fps as say a martial arts fight scene in a different movie, while the fight scene is a blurry mess, it's because that jerky motion is created by dropping the shutter angle to 45degrees creating a movie that is a series of individual sharp frames, while a typical fight movie has a shutter angle of 360degrees so each frame fully and smoothly captures the entire motion without any gap.
Here's a youtube short of a fan (perfect example given what we're talking about) demonstrating it: https://www.youtube.com/shorts... [youtube.com]
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i was thinking something similar, then I realized that with a 25fps camera, it's made an entire rotation in the time the aperture was open. I was thinking more about taking pictures OF the drone. But if I was designing some automated machine to attack this thing, like another drone, putting a 120fps camera on it would give a decent picture of it. that's only about 1/5th of a rotation. Tracking software doesn't need to get a perfectly clear picture to track something.
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how does it see out?
At that frequency? Like a bat.
Now I wonder about harmonic dampening. Not sure it's really all that "invisible" if it sounds like a billion-strong army of mosquitos on meth at 200 yards and causes frogs to randomly explode..
Re:25 x per sec (Score:5, Insightful)
If it's spinning at that rate couldn't you have the camera synchronized to the spins so it's capturing a frame when it's turned to the same position? Kinda like the mechanism that allowed fighter planes to have machine guns mounted in front of the pilot and shooting between the propeller blades. Motion picture cameras are 24 fps.
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If it's spinning at that rate couldn't you have the camera synchronized to the spins so it's capturing a frame when it's turned to the same position? Kinda like the mechanism that allowed fighter planes to have machine guns mounted in front of the pilot and shooting between the propeller blades. Motion picture cameras are 24 fps.
An axially mounted camera would not ned to spin. Not invisible, but a much smaller thing to spot.
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but that's going to have to run on a motor spinning 25fps in the other direction. It could work if frictionless was possible though. I wonder if gyroscopes, low friction and a counter prop like a helicopter would make that feasible.
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but that's going to have to run on a motor spinning 25fps in the other direction. It could work if frictionless was possible though. I wonder if gyroscopes, low friction and a counter prop like a helicopter would make that feasible.
Yea, or maybe some sort of induction motor to create a counter rotation?
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Or let the camera spin and stabilize it in software. As long as you have an orientation reference it should be straightforward.
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You put cameras on every surface. You end up with a spinning 360 degree view that you can unspin programmatically.
I'm not really seeing an issue TBH especially with how small and thin cameras are these days and, indeed, that moving them continually combining them with other views from cameras in the same sphere means you can almost certainly build up a higher quality image than you would with a single camera.
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How to image (Score:1)
Perhaps the same way the rotating Pioneer 10 scanned Jupiter's image: one line at a time while slowly shifting the angle, then digitally gluing the long spiral together to form something familiar to non-dizzy humans.
And the world keeps getting scarier (Score:4, Insightful)
n/a
Cool (Score:2)
Vaguely less visible man! (Score:3)
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Actually, the "invisibility" is quite effective. You can see a demonstration by trying to spot the fan blades of an ordinary oscillating fan. If it weren't for the stand and protective grill, there would be very little to see. These drones eliminate the center axis, so there's not even a visible center spot.
Make a silent drone I'll be more impressed (Score:5, Insightful)
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Most security screens do not have audio.
Re: Make a silent drone I'll be more impressed (Score:2)
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Companies stick with what they invested in decades ago and don't upgrade?
I'm going to lock in that answer.
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I don't think that's really needed in this case, however, because:
1) We do have radar now and human visual tricks don't really matter to it, and
2) Purely optical detection is still trivial for non-humans, this hits exactly one intended blind-spot tuned just for us.
This is a one-trick pony, albeit that trick is very cool if you happen to be a deaf human without access to a variable frame rate camera (e.g. any cheap modern
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And yet one example doesn't disprove the wider industry.
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If the situation requires radar, we use radar. If the situation requires strong passwords and MFA, we use strong passwords and MFA. And if the situation calls for giant concrete acoustic mirrors - Yes Virginia, that's why the UK coast is dotted with exactly those.
Old news. (Score:2)
Make a silent drone I'll be more impressed.
Those are old news, friend. https://s.abcnews.com/images/P... [abcnews.com]
Not too worryng (Score:2)
The range and payload penalties will be enormous.
If only we couldn't hear. (Score:2)
I mean on the camera they used, yeah it is harder to instantly see. But that only really helps if you're not looking for it, or it goes by pretty quickly.
Or if it had VERY good sensors that could work from a long distance... I guess that might offer something.
I mean unique solution to the problem, sure.
Now try this (Score:2)
Re: Now try this (Score:2)
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Might be even better if like a chameleon it had some lcd panels that could give off the average color of whatever it's trying to blend with. In the video, it looks extremely invisible against a gray background, because the drone is grayish. But it's not that great against a green background. If it could change to green, or to white, or to black, depending on the background, it would be excellent.
Also, we already a form of invisibility. It's called cover of darkness, and operating at night. Most stealth
Flying Saucers (Score:2)
People keep saying it's hard to get a non-blurry picture of them.
Some have suspected somebody has gravity bubble tech which would bend the light.
This thing just spins but isn't itself a disc, though on average it's s disc while in motion.
Post WWII-Germany/Paperclip there were more visible saucers seen over Washington and such but the Germans were developing solid discs. The blurry ones are more over the past few decades as drone tech has become common.
Curious.
Ukraine (Score:2)
Send the plans to Ukraine. They're good at this stuff, they'll figure out how to make it bigger.
Nothing new (Score:2)
An SEP is something we can't see, or don't see, or our brain doesn't let us see, because we think that it's somebody else's problem. Thatâ(TM)s what SEP means. Somebody Elseâ(TM)s Problem. The brain just edits it out, it's like a blind spot.
The Somebody Else's Problem field... relies on people's natural predisposition not to see anything they don't want to, weren't expecting, or can't explain. If Effrafax had painted the mountain pink and erected a cheap and simple
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Thatâ(TM)s what SEP means. Somebody Elseâ(TM)s Problem.
The thing is, you're iPhone is pretty much your problem. It makes you look stupid, not Slashdot.
Was an OS Trek episode where they (Score:1)
thought insects got aboard. They heard buzzing but nobody could actually see any insects. It turned out to be a race of beings who function at high speed, moving so quickly that humans couldn't see them.
They should remake a spy-drone version of that episode. The drones predict if somebody is about to swat at them and quickly shift out of the way.
One word: Manhacks. (Score:1)