Comment on Wind-Tolerant, Autonomous Drones Could Cut Bridge Inspection Costs by 30%
JimmyMcGill@lemmy.world 9 months agoWhen you do bridge inspection you have to be real close to the structure. And basically stationary as well. You are looking for minuscule gaps and other damages.
You can easily do a 3D map from afar but that won’t have anywhere near the resolution required.
linearchaos@lemmy.world 9 months ago
close for a camera is just resolution. drone is there to provide an angle. This is a technical problem , not a time one.
JimmyMcGill@lemmy.world 9 months ago
It’s not just resolution
Its also stability/focus and speed
Get the camera with highest zoom you can and plop it in a drone and you will get shitty photos. Drones have a ton of vibrations.
linearchaos@lemmy.world 9 months ago
“Its also stability/focus and speed” “Drones have a ton of vibrations.”
I think you’re conflating ‘drone’ with a $1000 consumer grade DJI. You can put whatever light, sensor or camera you want any one of a dozen stabilized platforms that are good up to 50 lbs. They’re still not any harder to fly, it’s still a one person job, you could make it two people and have the second person aiming and shooting you can do the work twice as fast.
“highest zoom you can” I didn’t say that, because it would be an intensely stupid statement to make.
If you want sub millimeter resolution of the entire structure, that’s doable. You want infrared? FLIR? all doable.
If you used a stabilized 50MP mirrorless with a fixed lens to take pictures from 10ft away, you could get 2.62 pixels per mm. If you reeled that in to 5ft at a time, you’d get 5.25 pixels per mm.
On a gimbal, with a stabilized lens, vibration would be a non issue. But if you want to beat that horse, you have 6 blades at 10krpm. The maximum frequency of the vibrations would be around 1000hz. (6*10000rpm/60) which means if you’re shooting faster than 1/1000 there’s no time for vibration even if it was completely un-stabilized. That’s easily doable with a light source. That said shooting at 800 would be more than adequate.
And there are cameras with higher resolution and faster sensors available. I’m just taking an upper end off the shelf Nikon at the moment to make the point.
laurelraven@lemmy.blahaj.zone 9 months ago
5.25 pixels per millimeter does not sound like very good resolution, especially for close inspection… Did you leave out a modifier or am I misreading something here?
JimmyMcGill@lemmy.world 9 months ago
First of all the other guy that replied to you wasn’t me. With all that rant you didn’t even notice that.
Second of all I actually work as en engineer in the Drone industry. I’ve written flight control software so I know a thing or two.
Third I actually know people working with drones in that specific industry in two different companies actually. In both cases these drones aim to get as close as possible to their target in order to do the inspection because that’s required. If a bridge has a crack that hasn’t been spotted and is already visible from a far, that bridge is already in a bad state. You are looking at basically micro gaps in your preventative maintenance. And no these aren’t 1k consumer grade djis (though DJI has fucking amazing hardware). I’m talking 5 to 6 figures and sometimes that just a lease.
Lastly that’s all very fancy math for vibrations. You should go work in state estimation if you can cancel it that easily. In the real world you have vibrations across the entire spectrum. Yes there are certain peaks and one of them is related to the motor rpm but it’s an extremely complex problem. Gimbals aim to stabilize the feed from a attitude pov with some damping but they aren’t foolproof.