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Author Topic: Two-fold alignment in point cloud  (Read 1055 times)

seamone

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Two-fold alignment in point cloud
« on: July 16, 2018, 05:49:10 PM »
Hi all.

First of all thank you in advance for your reading.
I'm in trouble trying to making 3D model of a set of rare abyssal fishes for the Spanish Institute of Oceanography. I made 151 photographies of the subject very accurately, using tripod and a f-value of f/18 on a 100mm macro lens, rotating around the subject with very constant lighting. When depth field was not enough and not all the subject was on focus I pointed to a certain area of the fish, shot it, moved slightly, pointed to the area that was out of focus before and shot again.
I successfully employed this technique with other models and everything went well.
What I'm obtaining now is a strange two-fold points cloud, with most of point correctly aligned and a large part of them misaligned over a symmetric and specular fold of the original cloud.
Please see the attached figure to understand what I mean.
Photo alignment with High quality, generic pre-selection and adaptive camera model fitting enabled.
Any idea of what is occurring?
Any idea of how to detect the images responsible for the misaligned part of the cloud?
Any idea of how to force photo alignment to be coherent with the other part of the cloud?

Thank you in advance.
Best regards
Simone

danderson4

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Re: Two-fold alignment in point cloud
« Reply #1 on: August 02, 2018, 11:22:28 PM »
are the points that are mis-aligning all from the same side of the fish?  Can you post a picture "zoomed out" so that it is possible to see the all the camera rectangles?  Also can you post a picture with the dense cloud rotated 180 degrees?

Alexey Pasumansky

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Re: Two-fold alignment in point cloud
« Reply #2 on: August 03, 2018, 01:43:28 PM »
Also it would be interesting to see, if there are any matching points found in the background, unless you are using masks?

And have you tried to reset the alignment for the incorrectly aligned cameras and run Align Selected cameras operation for them - does it help?
Best regards,
Alexey Pasumansky,
AgiSoft LLC