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Author Topic: aligning images with no geotags  (Read 1614 times)

dowallin

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aligning images with no geotags
« on: November 18, 2016, 08:25:24 PM »
Greetings.
I have a set of nearly 700 images acquired from a UAS on two flights on the same day. The images cover an area of about 200 m by 800 m. The images are not geotagged but I have a very good set of GCPs for the area that I can use to georegister the image mosaic after alignment.

I ran the "Align Photos" function on the full set of images using "Generic Pair Selection". The images from the second flight (covering the south half of the study area) aligned just fine but NONE of the images from the first flight (north half) aligned. Prior to running the alignment, I checked the image quality and all images has a quality well above 0.5.

I tried running the alignment a second time using just the images from the first flight and they aligned just fine. I then added the images from the second flight to this project and ran the alignment again. After doing so, the images from the first flight were no longer aligned but the images from the second flight were aligned.

Any suggestions on how to deal with this would be greatly appreciated. For prior projects, I've been able to use un-geotagged images, align them and then use a set of GCPs to georegister the image mosaic. 

Regards,
David

Alexey Pasumansky

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Re: aligning images with no geotags
« Reply #1 on: November 19, 2016, 12:20:22 PM »
Hello David,

Maybe there's not sufficient overlap between two flights?

I can suggest to take a couple of flight lines from both subsets in the area that is supposed to be overlapping and run alignment with the disabled interpolation. To check that the images can be aligned at all.
Best regards,
Alexey Pasumansky,
Agisoft LLC

dowallin

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Re: aligning images with no geotags
« Reply #2 on: November 22, 2016, 11:36:40 PM »
Alexey,
I can't see how this could be the issue. I'm using the Mission Planner software to control the flights. I have two identical quadcopters, each with Canon S100 cameras. Each camera is modified for different parts of the IR; one is red edge and the other in near-IR. Both quads flew using the same flight plan. The flight plans for the north and south parts of the study area overlap by about 30 m. I was flying at 90 m AGL.

The images from the rededge-equipped quad aligned just fine. But the images from the NIR-equipped quad do not. Again, if I run the alignment with just the images from the north, they align just fine. When I add the images from the south, the south half align but the north half now do not align.

I will go ahead and take a few images from the overlap zone and see if they will align and I'll post an update

Surya

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Re: aligning images with no geotags
« Reply #3 on: October 17, 2020, 07:00:07 PM »
@alexey I collected images using DJI Mavic enterprise 2 dual and built the models using visible images. But I am facing a problem in aligning the IR images following the multi-camera setup

1_When I import the IR images, it creates two sets of the IR images one with location coordinates and the other without
2) It doesn't automatically load the camera properties (focal length and pixel size) I kind of guestimated it

None of the images align whereas the same with visible images aligned superbly well.

Appreciate your help!