Refining generic alignment

[Arie]

Hello,
using the generic option for alignment has some major speed advantages but I've had quite a lot of situations where it produces fairly inaccurate results in comparision to the "disabled" align option.

Would it be possible to use the generic alignment as the basis for a finer alignment? For example using the camera-coordinates to run a second alignment using the "reference" option?

Edit: Or would it be possible to expose the parameters for the generic alignment?
This could be a trade-off between the higher accuracy of "disabled" alignment and the speed of "generic" alignment.

[Arie]

So, no chance in exposing the parameters for the generic alignment?

[frank.stremke]

wel you can always exort the camera position and orientation into a textfile  find the estimated there and import it back into the project and then run the allignment using reference
frank

[Arie]

Thanks. I've actually tried that but after importing the Agisoft .xml and selecting "reference" I get the message "camera coordinates are not availabe".

Am I missing something?!

[Alexey Pasumansky]

Hello Arie,

If you have camera coordinates, then Reference preselection option should work fine for you (if we are speaking of aerial surveys).

[Arie]

Hi Alexej,
in this case it's not about using gps-coordinates but rather refining an existing alignment. I've had a couple of cases where generic alignment delivers fairly inaccurate results, so I was hoping to refine the alignment using the computed poses for a more accurate alignment.

Of course, being able to decide oneself if accuracy or speed is prefered, would be ideal (setting parameters for generic).

Thanks for your reply.

[Alexey Pasumansky]

Hello Arie,

But what do you mean under alignment refinement?

Like Frank has suggested, you can export estimated camera orientations (from the Reference pane, not using Export Cameras), providing that project is referenced and then import them back as source values and perform the reference based preselection image matching.

But actually I'm not sure that you'll got any considerable difference between reference and generic preselction results for aerial datasets.

[Arie]

Ups, sorry for throwing undefined terms around. I mean increasing the accuracy of the camera alignment.

I'll give your suggestion a try, do a comparision and get back to you.
Cheers.

[Arie]

So, i've tried to replicate the situation and stumbled across some issues.

Since the original dataset was too large I just ran several alignments on a subset of the imagery in the area where larger errors occured. Interestingly enough, suddenly I was not able to align all the images using the "generic" option.

Attached are some screenshots, the original "generic" alignment was done with a version before 1.2. Here one can see the error in the dense reconstruction, that occurs between two rows that do not have a lot of overlap. Next to that screenshot is the dense reconstruction based on the "disabled" option. The errors are gone.

With 1.2.3. I can't get the two rows to align at all using the generic option. The "disabled" option on other hand aligns them without a problem and the dense reconstruction shows no errors.

The difference time wise is 7h 28min for disabled vs. 50min. for generic, which brings me back to my original question. Any chance on exposing the generic parameters (for example as advanced settings)?
Cheers!