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mapillary / OpenSfM

Open source Structure-from-Motion pipeline
https://www.opensfm.org/
BSD 2-Clause "Simplified" License
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Multiple planes of points at different angles #951

Open dicobrazz opened 1 year ago

dicobrazz commented 1 year ago

Hi,

The reconstruction has multiple planes of points. I have tried with different sets of images, sometimes it's very drastic - two almost perpendicular planes, as if the point cloud data was randomly split into parts and then rotated. To clarify attaching a screenshot.

One thing that comes to my mind is that it might be because the images are shot at different angles. Some at 90 degrees and some all the way to 45 degrees. Unfortunately, I cannot share the images, but maybe you have some clues for me.

image

Regards Pavel

fabianschenk commented 1 year ago

Hi @dicobrazz ,

How many reconstructions does your output contain? It can happen that there are two or more because some images couldn't be matched. Also, if there's only little overlap, then it's very cheap for the bundle adjustment to move the reconstructions around this position. In the screenshot you seem to have 2 densely connected areas that look alright but they are not very well aligned with each other. I'd recommend to make sure that you have enough overlapping images in the "problematic" area.

Best, Fabian

dicobrazz commented 1 year ago

Hi @fabianschenk,

There is only one reconstruction. There is a very small overlap between images. Also, the photos have been taken at different angles. There are about 5 passes, each at different angle, between nadir and all the way up to about 45 degrees. Each pass has an overlap about 10% for all photos within and there is more overlap between photos from different passes.

Overall, it is a complicating dataset and I am trying to figure out how tune in for best possible result.

Regards Pavel