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Author Topic: Remove background from model  (Read 4058 times)

CarlosVenator

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Remove background from model
« on: October 20, 2019, 03:12:26 PM »
Hello everyone,

I have scanned a skull, aligned the photos, and now I've just created the dense point cloud. But the background is included in the model in such a way that it's impossible to manually remove it. Is there a way of doing this? Perhaps a step I've missed?

Thank you in advance to everyone for their help.

Best regards,
Carlos


cbnewham

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Re: Remove background from model
« Reply #1 on: October 20, 2019, 05:42:45 PM »
Is it a plain background? Others will be more expert on this, but it looks like you have a lot of points that are from the background generated at the wrong distances because the background had no features. I suggest you mask the background in every image.

It looks like you are using a turntable and I've never done photogrammetry that way, so others may have more experience and be able to make other suggestions.

CarlosVenator

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Re: Remove background from model
« Reply #2 on: October 20, 2019, 05:50:06 PM »
Hi there!

Thanks for you answer. Yes it's a plain white background. I'm indeed using a turntable. I can't mask every photo because there are 500 photos in total. I've tried masking them automatically with photos of just the background (without the skull), but since these masks aren't perfect, every time I've tried it this way there were lots of problems when aligning...


CarlosVenator

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Re: Remove background from model
« Reply #3 on: October 21, 2019, 09:22:53 PM »
Does anyone have an idea?

Alexey Pasumansky

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Re: Remove background from model
« Reply #4 on: October 21, 2019, 09:27:10 PM »
Hello Carlos,

Have you tried to apply the mask from background images to the subsets of the photos (top and bottom parts) after alignment and prior to the dense cloud generation?

Also I can suggest to try building mesh from the depth maps, as it uses additional noise suppression methods.
Best regards,
Alexey Pasumansky,
Agisoft LLC

CarlosVenator

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Re: Remove background from model
« Reply #5 on: October 21, 2019, 10:13:04 PM »
Hello Alexey,

Thank you for your help. Yes I've manually masked about 50 photos out of 500. And after generating the Dense Cloud, I've tried to "Select Points by Masks", but doing it this way it also selects parts of the skull... Is there maybe a way to edit and decrease this selection obtained from the masks?

I've tried building the mesh with depth maps, but the turntable also appears in the model.
« Last Edit: October 21, 2019, 10:16:29 PM by CarlosVenator »

CarlosVenator

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Re: Remove background from model
« Reply #6 on: October 22, 2019, 05:08:36 PM »
Have you tried to apply the mask from background images to the subsets of the photos (top and bottom parts) after alignment and prior to the dense cloud generation?

Hi Alexey,

This is the selection generated from the masks. It's a shame because the selection includes parts of the skull as well, even though the masks are perfect. Isn't there a way to decrease the selection a bit? If there is, then the problem would be solved.

Regards.

Mak11

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Re: Remove background from model
« Reply #7 on: October 22, 2019, 05:12:41 PM »
Carlos,

Why don't you try to delete the unwanted points manually using the free-form selection tool in addition to "select points by color" ? It should literally take only a few minutes and give you better results.

Mak

CarlosVenator

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Re: Remove background from model
« Reply #8 on: October 22, 2019, 05:21:20 PM »
Carlos,

Why don't you try to delete the unwanted points manually using the free-form selection tool in addition to "select points by color" ? It should literally take only a few minutes and give you better results.

Mak

This would definitely not take just a few minutes, it would rather take days. There are too many points, and they're too close to the model of the skull for me to remove them manually, it's just not feasible. I've tried to select points by color as well, but it also selects parts of the skull, even if I lower the tolerance. But it makes me reduce the tolerance to such a degree that it barely selects any points and I'd still have to do pretty much all the work manually...

The best way would be to decrease the selection generated by the masks, since they were perfectly adjusted to the skull. If this function exists, of course.

Alexey Pasumansky

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Re: Remove background from model
« Reply #9 on: October 22, 2019, 05:40:42 PM »
Hello Carlos,

Is it possible to share the project in PSZ format with the alignment results and applied masks and the original images, so that we could try to suggest the proper workflow for such project?
Best regards,
Alexey Pasumansky,
Agisoft LLC

CarlosVenator

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Re: Remove background from model
« Reply #10 on: October 22, 2019, 06:25:25 PM »
Is it possible to share the project in PSZ format with the alignment results and applied masks and the original images, so that we could try to suggest the proper workflow for such project?

Hello Alexey,

Yes of course, that would be excellent! I only can't share it publicly, but if there's an email I can send it to, I'd be happy to do that.

Regards

Mak11

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Re: Remove background from model
« Reply #11 on: October 22, 2019, 06:28:12 PM »
Carlos,

Upload it to https://wetransfer.com/ and send the link to Alexey -> support@agisoft.com

Mak

CarlosVenator

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Re: Remove background from model
« Reply #12 on: October 22, 2019, 07:07:05 PM »
Hi again Mak,

Thank you very much! I'll do it right away.

Regards.

JMR

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Re: Remove background from model
« Reply #13 on: October 25, 2019, 02:07:37 PM »
I've done a pretty similar jobe last week. I'll gladly guide you through the process.
https://skfb.ly/6O6wF

Geobit

Alexey Pasumansky

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Re: Remove background from model
« Reply #14 on: October 27, 2019, 02:47:41 PM »
Hello Carlos,

Thank you for providing the project data. I've performed the following steps:
- generated rough mesh model from the sparse cloud,
- generated masks using From Model option,
- generated mesh using depth maps source.

I'll send you the project, once it is uploaded.
Best regards,
Alexey Pasumansky,
Agisoft LLC