Drone2Map imagery quality

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09-27-2021 07:05 AM
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BillLotz
Occasional Contributor II

Hello,

I am processing drone imagery shot with a Mavic Pro.  It was flown using drone deploy at 200' with 75/70% overlap. Two acres, 113 images, in a crosshatch flight patch. the raw imagery is great, but when processed imagery is not. after numerous tries I reset Drone2map to the default setting s and tried again, but got the same results.

 

I have attached a screenshot showing the raw imagery and the processed, any suggestions?

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TrentReeder
Occasional Contributor

You might try bumping up your overlaps too.  85/75-80%.  There's always diminishing returns when there's too much overlap, but with areas with a lot of visual variability (forested areas, varied terrain, etc...) it can help.

View solution in original post

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TrentReeder
Occasional Contributor

You might try selecting the Rolling Shutter Optimization option in the Edit Camera settings.  You can also try in the Processing Options -> Initial, select the Use Geometry Verified Matching.

TrentReeder_0-1632752369119.png

Depending on what your project goal is, if a nice orthomosaic is required, running a NADIR lawnmower pattern can be the preferred method.  If having a nice 3D product is the goal, then that is where the crosshatch flight comes in.  If you haven't already, search crosshatch overlap on the DroneDeploy forum and there are quite a few discussions about what works best in various scenarios.

Hope that helps.

 

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Brooks_SummitGeo
Regular Contributor

@BillLotz I don't profess to be a D2M expert as I use other software for photogrammetry, but the terminology is largely the same across platforms:

1. have you enabled ghost filtering in the orthomosaic creation?

2. does D2M support RGB point cloud classificaiton? If so, can you classify ground points, build a DTM from just the ground points, then re-run the orthomosaic creation using the DTM as your surface? This would resolve any strange artifacts in vertical components of the ortho, becuase it wont be trying to interpolate down the sides of vertical structures.

3. enable rolling shutter correction as @TrentReeder  suggests.

4. can you edit the seamlines in D2M like with other software and redraw around objects with poor image quality to replace the image being used?


David
..Maps with no limits..
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BillLotz
Occasional Contributor II

Thanks for the reply. I have had the rolling shutter option selected, might have gone away when I went back to the defaults, but I believe its elects it based on the camera information. I will check it and try your other suggestions.

I have used the lawnmower option (I figured that I would try the cross hatch) and am going to try another test using it later today. 

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Brooks_SummitGeo
Regular Contributor

@BillLotz you really shouldn't need a crosshatch unless you're flying obliques for 3D modelling. You just end up with additional processing time. If you're after a clean ortho, then processing ortho from a clean DTM is the way to go. use aggressive point cloud filtering


David
..Maps with no limits..
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TrentReeder
Occasional Contributor

You might try bumping up your overlaps too.  85/75-80%.  There's always diminishing returns when there's too much overlap, but with areas with a lot of visual variability (forested areas, varied terrain, etc...) it can help.

View solution in original post

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BillLotz
Occasional Contributor II

Thanks for all the suggestions. I did bump up the overlaps to 80-70%, but I will try the 85-80%, and went back to the lawnmower pattern. The rolling shutter is selected, I'll look into the suggestions, but I don't believe I can control the seam lines.

I'll se what happens and report back.

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BillLotz
Occasional Contributor II

Better results with the overlap at 80-70% and the Processing Options -> Initial, select the Use Geometry Verified Matching as Trent suggested. The building edges got a little rough between the 2 building, but a big improvement. I'll try a park tomorrow, as long as the wind dies down, with the overlap set to 85-80%.

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BillLotz
Occasional Contributor II

I flew a park with several structures yesterday. Increased the overlap to 85-80%. Overall it looks good, but I did lose the edges of the roofs that were on the shadow side of the structures. Any suggestions on fixing this?

BillLotz_0-1632919103631.png

 

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Brooks_SummitGeo
Regular Contributor

@BillLotz you can use Agisoft Texture de-lighter, which is an awesome free tool that removes shadows from images https://www.agisoft.com/downloads/installer/ 

There are other ways of doing it in Adobe Lightroom, but this tool is pretty decent.


David
..Maps with no limits..
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