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Author Topic: Orthomosaic from large aerial dataset issues  (Read 1134 times)

remco.kootstra

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Orthomosaic from large aerial dataset issues
« on: November 23, 2022, 12:58:38 PM »
Hi,

I'm having some issues with generating Orthomosaics from large aerial data sets.

Data is from a PhaseOne iXM 100 camera and flown top down and also oblique at 45 degree angles.
The dense mesh and the tiled mesh looks absolutely fantastic.
We also need to generate orthos from this data.

When I go the DEM route the estimated calulation time for one ortho is over 12 days! for around a 4000 image chunk.

So I decided to go the 2.5d Heightmap route and genrated a height mesh from the densecloud and used this as the base for generating the orthomosaic.
Timewise this works very well and the Ortho looks ok, apart from the edges of buildings etc.

I attached some screenshots

If you looks at the otho you can see the jagged edges at the roof edge. This is visible everywhere.
The mesh you see is the generated 2,5d mesh..  as you can see there you also have the jagged edges, so it's logical they are also visible in the otho itself.
Finally there's an image of the DEM which looks much smoother.

Using the DEM for the ortho results in long calculation times.

Does anyone know what the best route is to generate orthos from large aerial data? and getting better results when using the 2,5D mesh?

Thanks in advance.. 

DayGeckoArt

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Re: Orthomosaic from large aerial dataset issues
« Reply #1 on: November 27, 2022, 07:06:36 AM »
I haven't created any orthomosaics from that many photos but what I always do is make a medium or high quality dense cloud, then create the DEM, and then the orthomosaic. I don't ever make a 3D model first, unless I want my final product to be a 3D model

DayGeckoArt

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Re: Orthomosaic from large aerial dataset issues
« Reply #2 on: November 27, 2022, 10:29:25 PM »
On my viewer you can see my orthomosaics made with the DEM as the base https://arcg.is/1Krum81