'Reference' based image alignment - images divided in 2 groups

[osima]

Hi,

I work with a set of geo-tagged images acquired in one strip with >90% forward overlap and try to align them using the 'Reference' pair selection method. The images are nadir looking but I set the average terrain height anyway. I am aware of the fact that single image strips are far from being optimal for photogrammetric image processing, but I try to understand why the image set is always aligned in two groups (see attachment). Images within each group are aligned correctly, but in between the two groups alignment is incorrect. Initial image geo-location (GPS positions) looks logical and correct (with reasonably equal spacing between successive images in the strip), but Photoscan doesn't even look for matches between the last image in group 1 and the first image of group 2. Any suggestions on which parameter could I tune to avoid this behavior? Processing data using Generic or Disabled pair selection mode is much more time consuming....

best,
Ola

[bigben]

Are all of the images aligned?  If it didn't align one or two images that may result in a break in the strip.

[Alexey Pasumansky]

Hello Ola,

Can you please send this project to support@agisoft.com?

[Alexey Pasumansky]

Hello Ola,

Thank you for providing the project file. I can see that there are only 5 reference positions for 200 cameras (so there are about 40 cameras with exactly the same coordinates), it could be the source of the problem. So I can suggest to run the alignment with the following settings: High accuracy, Generic (or disabled) preselection. Also you can try setting tie-point limit to zero instead of 1000 (default value).

[osima]

Hi Alexey,

Indeed, I interpolated image positions in between the points and the image alignment (Reference based) was successful.

Thank you for your prompt support!

Best,
Ola