Pipeline Detailed Inspection - What's the best methodology


#1

Hi guys, I’m having some troubles creating a good quality 3D scan of a pipeline using my P34K and I’m hoping someone can assist with some troubleshooting for me please.

I understand that I could just fly a nadir mission and it would probably give some ok results, but for this I’m really wanting a detailed model showing the sides and underside supporting structure etc.

I flew a 200m length of a water pipeline, first run was scanning it at a low oblique angle (as I wanted to capture the footings and as much of the underside as I could), then I scanned back to my original start point but this time nadir from above, then lastly I did the side (oblique) scan of the other side. My thinking was that this should give me the best results as I was close (around 10m from the pipeline) and I was getting coverage of all angles.

Initially I ran the images through the ‘structure’ template on DD and the results were poor and patchy. Then I ran the same images through the ‘terrain’ template and it was less patchy but the accuracy of the form was terrible.

I’m wondering if my methodology was sound, but it was just that I did not have sufficient overlap on my imagery for the resulting model to be good. Or is there a another way that I should conduct my mission in order to get better results. Does anyone have any ideas they can share please?

I’ve uploaded some pics below, the first two are using the ‘structure’ template, the second two are using the ‘terrain’ template. My flight ID is: eb8bea2b26_THEAEROSCOOPENPIPELINE

Thanks in advance.

Jas


#2

Your overlaps are probably not sufficient to allow good stitching.
I would fly over it with a autonomous grid pattern getting three to four rows of images using DD.
Then I would fly along each side sideways using the DJI app looking down about 45 - 60 degrees (no sky in the images) to get better 3D features of the sides and underneath. You might want to do the side shots at two altitudes.
It needs the overhead shots to have reference features to align and stitch the side shots with so don’t fly extremely close.


#3

Hey @TheAeroScout, if it helps, once you get your 3D model to look slightly better, you can try doing the actual inspection in Scopito (find it in the app market in DD). We are here to help :slight_smile:


#4

Thanks for your suggestion Dani-Scopito. I’ll have to get a quick tutorial from you on how I get my DD model over to Scopito and then how I use it for an inspection report please.


#5

Guys, I’m still having real troubles with mapping/scanning this pipeline.

I went back yesterday and this time scanned it three times in nadir (one each side of the pipe and one directly over) … I also then went and scanned each side at around 45 degrees oblique, finally I walked along its length taking direct side pics by holding the P3 (props off) and facing it at the pipeline.

I’ve set it to process under a ‘terrain’ template and I excluded the side images and it’s produced nothing, as in there’s no 2D and the 3D is not a model at all.

Have I uploaded too many images? Do I have too much overlap? I used two batteries for this mission and took off in two locations, the overall elevation difference between the two start locations was about 5m, would this make a difference? I would have thought that the stitching would over-ride any differences in GPS EXIF data.

Any help would be appreciated. Flight ID: 3b0212efae_93FF871A05OPENPIPELINE

Thanks in advance.

Jas


#6

Linear flight app with 1 row that will create a path up one side of the pipe and down the other. I you are trying to accurately get to the bottom of the pipe you are going to have to get as low as you can without seeing the horizon with the obliques, but there is no flight pattern for 45deg looking perpendicular to the pipe so I use Litchi with a defined heading on each side. I also post-process the images to remove the shadow under the pipe to get more tie-points.


#7

@TheAeroScout Unfortunately this map will not come out too well You are too close to the pipe to adequately allow our map to create tiles and stitch. I would recommend flying about 100 feet, map overlap setting to 90 percent. I would also would recommend our linear mapping app which can be found here https://www.dronedeploy.com/app-market/flight/rsuhocmefpmvjimlqedb.html

Thanks and good luck!

Yusuf


#8

Hi Yusuf, thank you very much for your advice.

Can you explain to me a little more (so I know for next time) how the tiles and stitch are created and why being too close affects them?

Cheers,

Jas


#9

The closer you get the less tie-points you have.