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Author Topic: Loss of detail in model  (Read 1434 times)

Robboo

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Loss of detail in model
« on: August 08, 2018, 04:16:24 PM »
Hi All,

I'm creating a model of a cultural heritage object with over 200 images that have passed the image quality analysis in Agisoft. Although all images are masked and align properly my resulting model has small gaps in some areas, that otherwise have detail in many photos(see attached images).This model will be used as an animation or screen display with the artifact, and possibly printed.

How do I fill in this detail or regenerate a model that maintains it. I've done several successful projects but this one has stumped me. Does this need to be fixed in an external editor and which one? Thanks in advance for any advise.

Alexey Pasumansky

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Re: Loss of detail in model
« Reply #1 on: August 08, 2018, 05:02:07 PM »
Hello Robboo,

Which meshing method you are using - regular arbitrary reconstruction from the dense cloud or experimental (visibility consistent) method that uses depth maps on input?

Such reconstruction artifacts may be related to the thin structure of the two-sided surface.

If you have time for experiment, I can suggest to try the experimental method and see, if the result is better (see related tutorial: http://www.agisoft.com/index.php?id=48).
Best regards,
Alexey Pasumansky,
Agisoft LLC

Robboo

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Re: Loss of detail in model
« Reply #2 on: August 08, 2018, 10:28:22 PM »
Alexey,

Thanks for your reply.  I will try that process on my desktop Mac tomorrow. It was sceduled to require 10+ hours to generate on my laptop. Also, I’d already generated mask for every image previously. Do you recommmend that I only use mask for 1 or a few images. Does it affect the time if all images have mask or not? I’ll keep you posted on the project.

Robboo

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Re: Loss of detail in model
« Reply #3 on: August 09, 2018, 08:30:14 PM »
Hi Alexey,

I attempted the technique that you suggested with no success. I began a new project with the same data and masked a few of the 311 images in the project. I could not get the images to align until I created new mask form background for all the images.

When I attempted the Strict volumetric masking technique with all the mask created, the proposed processing time was over 20 hours on a desktop with 64mb ram. As you mentioned, the mask extends the processing time significantly but I could not align the project without them. Can the mask be removed after the dense cloud is built and prior to building the mesh.  I'm not sure where to go from here to improve the errors (gaps in detail) of the prior model. I was very hopeful that this would be the remedy but I may be missing something or doing something wrong? Any help is appreciated.

Alexey Pasumansky

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Re: Loss of detail in model
« Reply #4 on: August 09, 2018, 08:37:06 PM »
Hello Robboo,

I suggest to use only visibility consistent mesh generation, no need to apply strict masking.
Best regards,
Alexey Pasumansky,
Agisoft LLC

Robboo

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Re: Loss of detail in model
« Reply #5 on: August 14, 2018, 06:23:24 PM »
Hi Alexey,

I just tried the new technique for mesh generation. ( visibility consistent mesh generation) and it was a great improvement over the prior model. Thanks so much for your help!

Robboo

Alexey Pasumansky

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Re: Loss of detail in model
« Reply #6 on: August 16, 2018, 07:01:33 PM »
Hello Robboo,

If you have some spare time for additional experiments, you can also try to run Refine Mesh operation over the newly built mesh, as it would likely improve the quality of the small details on the surface (but the polygon count will be also increased for the model).
Best regards,
Alexey Pasumansky,
Agisoft LLC