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Darpa Seeks Tools to Capture Underground Worlds in 3D

darpa.mil

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Re: Darpa Seeks Tools to Capture Underground Worlds in 3D

#11

Post by krisoft »

jeffchuber wrote: post #6
zeristor wrote: post #3

How far are built in phone gyroscopes from providing inertial tracking for underground, it would be handy to walk around Tube stations and see how there're all connected, but the accuracy seems to be someway off. Although this looks to be a lead: https://aaltovision.github.io/handheld-INS/assets/presentati...

too much drift, they are very noisy. double integration is hard.

Just to expand on what my parent poster said: double integration is hard, not in the "hard to get the implementation right" sense, but in the "even with perfect implementation the small errors add up fast, and the uncertainty grows out of all practical bounds". I'm just saying this because even very smart people can fail into the trap of "we just need a better kalman filter".

Re: Darpa Seeks Tools to Capture Underground Worlds in 3D

#12

Post by mparr4 »

zeristor wrote: post #3

How far are built in phone gyroscopes from providing inertial tracking for underground, it would be handy to walk around Tube stations and see how there're all connected, but the accuracy seems to be someway off. Although this looks to be a lead: https://aaltovision.github.io/handheld-INS/assets/presentati...

Pure inertial navigation gets worse over time, even a $20,000 gyroscope wouldn't get the job done.

This is because gyroscopes measure rotational velocity, velocity is the first derivative of position, so you need to integrate velocity in order to get rotational position. The integral of velocity is (velocity x time), so your error gets bigger over time.

I'd imagine an inertial solution plus optical flow could result in some pretty good results.

Re: Darpa Seeks Tools to Capture Underground Worlds in 3D

#13

Post by aaron695 »

I wonder what the real mission here is?

Unlike the entertaining but comical scene in Sicario, tunnels IRL are just very simple one way affairs.

Here's an ISIS tunnel - https://edition.cnn.com/videos/world/2016/10/19/iraq-mosul-i...

Not really different than lets say fighters in a bunch or trees our buildings really? Concussion explosions are more dangerous, but you can't be flanked. It's a little different sure, but no more worthy of flying mapping drones.

Maybe DARPA is just seeing what comes out of it as per their mission. A lot of respect for the way they work. But a little sus there's more to it.

I always suspected their sewing robots project was less about cheap uniforms and more about destabilizing economies of other countries. But I'm a cynic.

Re: Darpa Seeks Tools to Capture Underground Worlds in 3D

#14

Post by Frost1x »

blh wrote: post #4
zeristor wrote: post #3

How far are built in phone gyroscopes from providing inertial tracking for underground, it would be handy to walk around Tube stations and see how there're all connected, but the accuracy seems to be someway off. Although this looks to be a lead: https://aaltovision.github.io/handheld-INS/assets/presentati...

For larger environments you tend to need a full-blown SLAM system that can close loops to avoid drift that accumulates inevitably.

They also want to create dynamic meshes on the fly for use in OTS game engines which is quite a challenge.

I'm not sure why everyone in that domain is obsessed with meshes and won't work with a voxel rendering system which seems more flexible for most types of current geometry capture techniques. I get that they want to reuse existing simulators using existing gaming technologies but sometimes its fitting a square car through a round garden hose.

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