Bridge Inspection – LiDAR Drone Data review with DJI M300 and ROCK R2A
Its an abandoned route, 66 bridge – i believe you used to have a road going across it – maybe railroad track. I dont really know, but i thought it was really cool. I said why dont i go out there and capture this data set, because this is going to be really cool, so this was flown in completely manual mode. So i manually flew this structure. I flew three passes on it and im going to go over my first impressions of the data set. What i could have done to fly it better and capture more detailed structure out of this system and then also just any other findings that i see whenever im. Looking the data so lets just jump right into it, so this right here is that bridge that i flew and i actually lets zoom out and kind of go over how i flew it first, it means first, it looks awesome like this. This looks really really good. I was standing right here at the end of this bridge. This is the route 66 state park in in missouri, and i stood right here and i flew all the way down to the other landing, which was all the way over here and then i flew back and down again and then i kind of went up in The air and just zoomed back to me, so i did three passes, one right down the center one off the left and one off the right and i flew it about.
I was about probably 20 to 30 feet off of the structure at any given time, and you see the detail, looks pretty amazing. Now one thing im seeing right away, see these black spots right here on the bridge, and this is step one of what i could have done better to capture the structure, even better uh. The trigger interval of the camera thats attached to the lidar was set about three seconds, and i think if i would have pushed that down to one second, it would have captured more photos on the sony camera which is attached to lidar and that would have colorized That in because what ended up happening is, i was flying so low and so fast along this structure that the one photo to the next photo. I didnt capture this piece in that photo so theres, just a missing piece in that photo and thats. Why it didnt get colorized makes sense, but you can actually see in the elevation view of the data that it is all there you know so there there is data right there and then heres something else. Thats interesting now look at this, so you can see. It looks like theres a little bit of a mismatch there. What exactly is that lets? Take a look lets go to gps time, okay, so we can see. This is actually from Music, green and blue, which is two different times. So if i zoom out, you can actually see this is my one.
Two three passes that i flew and if i look at this right, i i dont think its actually any mismatch. What i think it is is i didnt capture. It was an included side of this so yeah. When i came for the green side, it was getting a little bit more on this side of the structure. When i came from the blue side, i got a little bit more on this side of the structure. So probably what i could have done, i could have flown a down and back on the left hand, side a down and back on the middle and a down and back on the right just to make sure if there was any occlusions i was getting. That would have been covered, but in all actuality. What i would probably do today is, i would use our new new facade mount that weve been working on. That gives us the ability to take the ladder and actually move it to different angles, and then i would have flown those multiple passes just to make sure i got all those different angles, but this was meant to be just a just an example. Just i was just curious: how is it going to do you know total manual flight theres, no mission planning here its just line of sight. You know it was after a long day of work, and i saw this bridge i said hey, this looks pretty cool lets. Go and map it, so i went and mapped this uh.
What else so look at this is actually kind of interesting. Let me go back to this rgb, so you can see here in the this lattice structure inside of these uh, these beams its like hollowed out here like a little little lattices there. But then, if you notice over here its a solid, i beam construction. Now i wonder why they did that. I bet i bet if we measure, but if we measure these spans its going to be much shorter, so they were able to use the i beam. But this over the river was much larger span, so they had to use a different different construction in order to get that extra strength that needed so lets lets actually go ahead and just lets see, i dont know im going to go ahead and grab this measurement Tool im going to throw a point there and then move this point over here, so lets see lets kind of make kind of make it good lets go right in the middle, so this is about 131 feet lets just say its probably 132.. You know, probably so its like 132 feet between these two structures and then, if i come over here to where it goes back to this, i beam oh yeah, you can already see it. I mean it looks. It looks much shorter, but for the sake of it, lets go ahead and measure that so thats about 62 feet. Okay, that totally makes sense.
So this span is much larger, so they had to make this taller. They had to add extra elements, probably to save weight, because you know if we were thinking about objects under strain and you know tension and strain and compression. Actually, all the forces are actually just carried along the surface of a material. So really the the inside of a material doesnt really play much. It does place some in and your shearing and your ductile strength, but whenever youre youre bending something its all the forces are really concentrated there at the surface so having an element thats hollow, it enables you to make it lighter and then also you get this surface Area that you have of this three dimensional object, so that thats probably why they did that if i had to make an educated guess, that would be why that happened. Um. What else so lets lets? Take a look at lets come down here. You can see. I actually was, i had to like go up and down a few times, because there was some trees in the way, and so i was actually. If i looked down the barrel here, zoom out, i think there was some some trees yeah, basically right here, along the right hand, side yeah, i had to kind of go, go up and around those trees. In order to to make this happen, oh yeah, and this isnt a straight line so that measurement i was quoting earlier – was totally wrong its about 132 feet, though – and this other ones, probably about probably about 60 62 feet somewhere around there.
How wide is this lets see? It is thats not right. I think thats yeah, okay, thats way off lets grab that lets actually bring that up here. How wide are we? We are sitting right at id say about 32 feet if we make this extra precise, yeah, probably about 32 feet, uh thats, pretty cool, though i mean this data set, looks really cool im going to put it down the link below, so you guys can play with It as well feel free to do some measurements. Let me know what you think: what do you think i could have done to make this data set better? You know you always got to keep in mind. What is the laser scanner doing whenever youre scanning, so its laser beams theyre going straight in straight lines? You know theres no curves going on here, and this is a its doing – a line scan so its getting a straight line as you go forward across the top of the structure, and so with that facade scan, you can mount it sideways and then we can drop Down to the side, and we can get the side of the structure as much better, so these columns here would have been captured better. You know, i think thats going to be a really cool to see that in another video, because we have some cool data sets that we already captured using the facade scan and its its really cool uh.
I think its going to be a lot and then we also have some data sets. We captured taking the same, lighter this r2a and putting it on a vehicle mobile mounting, and then we also fly it on the drone kind of merge. Those data sets together, um yeah. Let me know what you guys think. What would you like to see in lidar data? I hope you kind of learned a few tidbits in this quick video about this uh. This trust structure bid video uh, i dont think dont quote me in all the structural analysis. This is just from some uh. You know engineering courses i took in school. I think its mostly still uh from my memory. Probably right, but you know, you know how it gets so were, were if you dont, do it every day designing these structures, then probably arent, saying it right, but one thing i do know is lasers and drones, so i do know how i can capture this site. Better and make it a make a better solid model, and i think by flying, like i said earlier down and back on, both the left, the center and the right and then also doing that facade scan and just merging all that data into one and thats thats. Going to be the best way of doing this, but for a friday afternoon and flying for 20 minutes think this was pretty good.