What may cause this scrappy result?

Hello,

I have been using ODM for several months and it works on most of my images.

I used to take photos at an altitude between 50 to 200 meters (using a programmed DJI mavic 2, overlapping rate at about 70%), and ODM always produces acceptable result.

Recently I am trying to stitch photos taken at 30 meters high. This time, however, ODM produces scrappy results (like the image below).

I have tired multiple times, and it seems that this only happens when the height is below 50 meters.

Why would this happen? And how can I fix this?

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scrappy_result

FOV likely too narrow to get adequate tie points at that height. Try using a slight forward camera angle, wider lens, and/or possibly changing minimum tie point parameters in ODM.

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You might be losing overlap too, since you’re flying lower. You’ll need more photos at that altitude.

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Eh @Saijin_Naib I just re-read our answers and I was just re-stating what you said. Don’t mind me; I’m slow haha.

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All good, you clarified another way to approach a possible fix that I didn’t explicitly state :slight_smile:

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I lowered the tie points parameter and it worked.
Thanks, guys.

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Can i ask which parameter is it?
I can’t see any Tie Points Parameter in WebODM configuration.

It’s min-num-features

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