Agisoft Metashape

Agisoft Metashape => General => Topic started by: cronair on March 20, 2020, 06:36:39 PM

Title: mixing accurate photo locations with inaccurate
Post by: cronair on March 20, 2020, 06:36:39 PM

Does it make sense to take handheld photos with inaccurate locations of a structure and mix them in with Phantom RTK accurate photo locations? Wondering if it would help make the 3D model look better. I was thinking about carrying the Phantom so I was using the same camera at least. Or is it better to use a full frame DSLR? And how would I process them with the aerial pictures?

Thanks!

Title: Re: mixing accurate photo locations with inaccurate
Post by: Alexey Pasumansky on March 20, 2020, 09:49:23 PM

Hello cronair,

You can adjust the accuracy values for the terrestrial cameras in the Reference pane and define the measurement accuracy. But actually such cameras can be just unchecked in the Reference pane, thus their coordinates will be ignored during alignment, optimization and georeferencing operations.

In general there's no problem in mixing different cameras in the same project, just be sure that the sufficient overlap between ground based and aerial images is provided (some oblique aerial images would be required).

Title: Re: mixing accurate photo locations with inaccurate
Post by: cronair on March 21, 2020, 12:14:06 AM

OK. So unchecking them lets them float so only the positions of the accurate photos are used. Got it. Thank you.

Title: Re: mixing accurate photo locations with inaccurate
Post by: cronair on March 23, 2020, 12:47:30 AM

I had a site I could test this on and I've tried it a few times and they aren't being used in alignment if they aren't checked. Am I missing something?

Title: Re: mixing accurate photo locations with inaccurate
Post by: JMR on March 23, 2020, 06:27:53 AM

Unchecked cameras are aligned, but their coordinates don't participate in equations, so they are not disturbing the bundle adjustment.
if you have cameras with high accuracy  and others with low, you can set specific  values for each: One by one by doble click in accuracy cell and then enter value, or in groups by multiple selection, then right click and modify... accuracy.

if accuracy is similar in XYZ then enter a single value i.e. 0.005
if horizontal accuracy is higher than vertial, you can enter the two values separated by "/", i.e. 0.005/0.015
if you had independent x,y,z, accuracy estimations, you can enter the three values in the same way. i.e. 0.02/0.03/0.05

Regards
GEOBIT

Title: Re: mixing accurate photo locations with inaccurate
Post by: cronair on March 24, 2020, 12:12:00 AM

There obviously could be more going wrong than just this since I'm still learning but this is what I am getting. You can see the roofline is not matching up. There is a gap of several feet when I align with all photos checked. And when I align without the ground photos checked, it says only a portion of the photos are aligned and it looks like all the ground photos were ignored. So it doesn't seem like they are aligned. Maybe I didn't take the ground shots in the best way. I did it kind of quick just to see if it would make a difference.

With accuracy, it appears it is showing the accuracies correctly but should I make the values bigger so it will move them more?

Thanks for the help.