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Author Topic: Pairing cameras to provide scale and minimise accumulation of error  (Read 5352 times)

Archaeology

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Recently I have been discussing the possibility of pairing two cameras together to provide an inbuilt scale for a photogrammetric model. It seems to me that if two cameras are used to take photos at the same time and at a fixed distance from each other (ie by fixing them both to a frame) then the distance between the camera positions in the final model can be entered and used to scale the entire model. You would still need to georeference the model but it would be very useuful in establishing scale.

Also this should improve accuracy because it would minimise accumulation of error in an image strip and reduce warping in the final model.

I don't know if it is possible to implement this kind of setup in Photoscan at the moment. There is an option to preselect image pairs but this is to do with feature matching and doesn't seem to imply a fixed spatial relationship between the image pairs. If it is possible in Photoscan I would love someone to give me some more info and if not then maybe I will head over to feature requests...

RalfH

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #1 on: January 19, 2014, 04:08:56 PM »
Hi,

this has been suggested before (http://www.agisoft.ru/forum/index.php?topic=916.msg4358#msg4358) and I still think it could be useful. Perhaps if the topic keeps popping up the feature will one day become reality.

Archaeology

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #2 on: January 19, 2014, 07:59:47 PM »
It seems to me that this should be relatively straightforward to implement. I'd like to hear what Alex has to say on it.

Alexey Pasumansky

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #3 on: January 20, 2014, 01:36:22 PM »
Hello Archaeology,

Currently PhotoScan supports scale-bar creation only between a pair of marker instances, but we are considering the possibility of scale-bars based on camera centers implementation.
Best regards,
Alexey Pasumansky,
Agisoft LLC

Archaeology

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #4 on: January 20, 2014, 01:37:55 PM »
that would be scaling a model that has already been aligned? what I am suggesting is something that would take place as part of the alignment process.

mrrafs

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #5 on: August 31, 2014, 03:49:45 PM »
+1

Patribus

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Re: Pairing cameras to provide scale and minimise accumulation of error
« Reply #6 on: September 01, 2014, 11:19:10 AM »
+1