Odm: Playing with resize-to and orthophoto-resolution

[clarkerz]

Hi,

Firstly THANK YOU so much for the effort and hard work you have gone to in developing ODM and WebODM!! It's greatly appreciated!! I managed to get both working (latest code form here) on an old AMD i3 dual booted laptop with Ubuntu 16.04, 4Gb RAM and 4 cores. It's not the most powerful but I've added a 64Gb swapfile on a USB3 which it rarely uses when processing the images. I wanted to try and improve the output of the orthophoto as it became a bit "pixely" when zooming into to 25M when imported to Google Earth. I read on here that reducing the resize and increasing the orthophoto-resolution can improve the output. I probably am being a bit picky as the output with the default 2400 resize is really good in any case.

I thought I'd share them on here (I hope that's OK) as I don't have an issue but more of a question really.

I used my DJI P4 rather than the Inspire as it's quicker to setup and used a forced-ccd of 20 on all 3 tests ( I read that somewhere that was correct but been able to revalidate again). For a comparison I used three different settings and zoomed into 25M on Google Earth with each imported tif and took a screenshot so I am hoping that is a valid test? All 3 took between an hour and hour and 15 mins with 90 photos (4000x2250).

The first was all settings default:

This is the second output with resize-to 3950 and orthophoto-resolution of 30:

This is the third output with resize-to 3999 and orthophoto-resolution of 60 which I think is awesome!!:

Hopefully I am doing this right but wasn't sure what the max and min parameters are the for the orthophoto-resolution but 60 appear to work really well. I couldn't find a don't resize option but when I set to 4000 it complained. Not sure if there is a way to be able to create your own defaults and save so you don't have change each time (I'm just being lazy :) )

Is there anyway to improve the 3D mapping. To reduce the number of holes etc and also the side of buildings etc and does it help to photo the buildings at a lower level as the guys at Drone Deploy suggest? Hope it's OK to post this here.. apologies if it's not.

Thanks again!

Cheers

Andy

[pierotofy]

Hey thanks for sharing the images Andy! They look pretty good!

Changing the orthophoto-resolution parameter is correct, but you don't need to change the resize-to parameter.

To get the side of the buildings you need to shoot photos from the side (example: set your target, then use the orbit functionality to take pictures from the side). Drone Deploy has a few articles on how to get that done.

We are currently working to improve the orthophoto results here #521. If you want a sharper textured model, increase the mesh-octree-depth parameter (set it to 12 or slightly higher).

[clarkerz]

Thanks for the information Pierotofy, greatly appreciated. That sounds great about improving the results and if you need any testing let me know! :)

Is there anywhere that explains each parameter and the max and min for each and what it does? i.e. what is the max for orthophoto-resolution etc? I'll try the mesh-octree-depth as well. Thanks again.

[pierotofy]

If you run:

python run.py --help

Reading the descriptions is the best documentation we have at the moment. You can also look at the source here: https://github.com/OpenDroneMap/OpenDroneMap/blob/master/opendm/config.py

I think we're looking to improve the documentation of the parameters as part of #516

[LucasMM86]

orthophoto-resolution is how many pixels per meter you want on the orthophoto.

[clarkerz]

Thanks both. I've used the Web DroneDeploy service just for some comparisons and they use the size of the area per pixel which confused me a bit i.e. 0.4in/px or 2in/px... as opposed to the number of pixels per area... I was just being a bit thick now I've worked it out. :) I am loving OpenDronemap!!! :)

Clarkerz

[clarkerz]

Just testing some more and it looks like the if I make the resize 3999 then the ouput file is much better. Also when I change the mesh-octree-depth to 12 I get a Segamentation Fault and then WebODM core dumps and if I try 11 then it bombs out and hangs. I'll leave at 9 as that works well.

orthophoto-resolution of 70, No forced-ccd and no resize

orthophoto-resolution of 70, forced-ccd 20 and no resize

orthophoto-resolution of 70, forced-ccd 20 and resize 3999 . I am well impressed with this as this is VERY zoomed in!! I don't think it's any better than orthophoto-resolution of 60 so that appears to be fine:)

[dakotabenjamin]

At some point you will reach the limit of the textured mesh's resolution.

[clarkerz]

Thanks. I reckon it's about 60..70 doesn't improve. Thanks. It's still good though! :) Andy

[BuffMyRadius]

Something that I would like to add for anyone searching for answers on how to up output resolution is that you can disable the input image resize with resize-to -1.