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Author Topic: Optimization errors  (Read 2543 times)

cjones1988

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Optimization errors
« on: February 19, 2016, 04:22:00 PM »
Hi everyone,

I am very new to PhotoScan so please forgive me if the answer to my question is very simple!

I am attempting to make an orthomosiac using GCP's. I have uploaded the photos (along with their calibration info - the photos have been aligned) and have also uploaded my GCP's and correctly identified them in all of the relevant photos; I am happy with their accuracy. Following on from this, i went through the optimization process. Firstly, i optimized with all the cameras still checked - this gave me error info within the 'reference marker' window. I then optimized with all the images unchecked - this made the 'model window' come up empty and also all my errors came up as 'nan' within the 'reference window'.

I am now unsure of whether this is correct? I was under the assumption that i should still have an error reading in the 'reference window' for the markers, and that my model should still be there? So, as to not waste time, i re-optimized the data with all the photos checked (to bring back the error values and the model image) and am now building a dense cloud (on medium quality) with only the markers checked. I am hoping that this was the right thing to do? Is anyone able to clarify that I am not wasting my time by doing this?

(Please note: I have uploaded a pdf with print screens to further illustrate the above paragraphs)

Any help/ advise would be greatly appreciated!

Alexey Pasumansky

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Re: Optimization errors
« Reply #1 on: February 19, 2016, 04:36:10 PM »
Hello cjones1988,

It seems that the problem is caused by using zero accuracy value for the markers. You need to specify Marker Accuracy (in meters) parameter according to the real measurement accuracy.

The suggested workflow for the dataset with the ground control points is described in the corresponding tutorial:
http://www.agisoft.com/pdf/PS_1.2%20-Tutorial%20(BL)%20-%20Orthophoto,%20DEM%20(with%20GCPs).pdf
Best regards,
Alexey Pasumansky,
Agisoft LLC

cjones1988

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Re: Optimization errors
« Reply #2 on: February 19, 2016, 04:46:56 PM »
Hi Alexey,

Thank you for your comments - I used that tutorial as a guide to help me so I am 99% certain that i did put those values in the 'reference settings' prior to camera optimization...

I forgot to mention in my original post; prior to setting the process chain running for the building of the dense cloud at medium quality, i ran it as the lowest quality - it only took two hours and produced a dense cloud that looked pretty decent; not overly sure if that helps!

Christine