Lake ortophoto

zarg404 · 21 June 2022 12:29

Hi,
I want to create an orthophoto of a lake survey with pictures taken at 120m, well above the surface. There are some bubbling coming out of the lake in some areas that we want to map.

For pictures with part of banks, the is no real problem. But pictures with only water and bubbles at the surface, the result is not horrible. As we know that the lake is flat (!), is there a way to tell ODM to use the pictures location to make the orthophoto ? I used SIFT
Thanks

One of the picture

Saijin_Naib · 21 June 2022 15:06

You might try the “Field” preset and see how that goes, but photogrammetric reconstruction of water is notoriously hard without real features.

Gordon · 21 June 2022 22:43

If you have some land features in each frame, then Hugin might be worth a try, but it wont be georeferenced.

zarg404 · 22 June 2022 13:19

How can I use the “Field” preset with ODM ? I am not using WebODM…
Thanks

Saijin_Naib · 22 June 2022 15:45

This is the group of settings for the Field preset:

github.com

OpenDroneMap/WebODM/blob/master/app/boot.py#L137-L140

      
        
            Preset.objects.update_or_create(name='Field', system=True,
                                            defaults={'options': [{'name': 'sfm-algorithm', 'value': 'planar'},
                                                                  {'name': 'fast-orthophoto', 'value': True},
                                                                  {'name': 'matcher-neighbors', 'value': 4}]})