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Author Topic: Ortho distortion  (Read 2918 times)

gmarc

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Ortho distortion
« on: October 28, 2014, 07:08:34 PM »
Any advice on how to make crisp clear orthos?  Attached is a common problem I'm having. I there a setting I'm missing
or filter?   Thanks

stihl

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Re: Ortho distortion
« Reply #1 on: October 29, 2014, 01:17:43 AM »
What you're seeing are 'True Ortho' artifacts. They're caused when Photoscan is trying to fill in areas of the ortho photo that have no data, not enough data or irregular data because of noise (such as on building edges).

The only solution for this - in Photoscan at least - is to use the ground filter to make a mesh of only the ground points. If you then export that as an Ortho, any object that's above the ground level will have object lean. This means that the ortho is no longer a so called 'True Ortho' but simply an orthophoto.

Unfortunately Photoscan does not yet provide a way of editing the seamlines in an orthophoto. So the end result might still be not what you wanted. Which is a shame because the quality of the ortho's is fine, except for the horrible artifacts.

I know that Photoscan v0.9.1 does a better job at delimiting the artifacts, but that version has a harder time with color balancing the entire ortho. They've changed some stuff from v0.9.1 upwards which gets the colors more accurate but also produces a lot more artifacts.

« Last Edit: October 29, 2014, 02:00:44 AM by stihl »