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Sharper photo overlay

Posted: Wed Nov 21, 2012 7:47 am
by mankoff
Hi,

I have a 3D model generated from photographs and the structure-from-motion algorithm in PhotoScan. A screenshot of that is here:
PhotoScan screenshot.
PhotoScan screenshot.
photoscan.png (115.08 KiB) Viewed 12743 times
When I export that model (PLY + JPEG) and import it into qCC, it looks like this:
qCC screenshot
qCC screenshot
cc.png (92.78 KiB) Viewed 12743 times
Why is qCC so fuzzy? The JPEG overlay appears sharp. Is there something I am doing wrong, or is this an implementation issue, in which case, should I file a feature to have sharper photo-realistic overlays as an option?

Thanks,

-k.

Re: Sharper photo overlay

Posted: Wed Nov 21, 2012 9:01 am
by daniel
Hi,

it's just a guess, but the result in PhotoScan seems to be a textured mesh. The mesh displayed in CC seems to only have an RGB field (and it can't be otherwise as PLY files doesn't provide a standard way to exchange textures, only texture coordinates - see http://www.agisoft.ru/forum/index.php?topic=16.0). If you can work with OBJ format it would be preferable.

However I never encountered a PLY file with texture-related information. I would be greatly interested in it.

Re: Sharper photo overlay

Posted: Wed Nov 21, 2012 7:02 pm
by mankoff
Yes the OBJ file makes it look just like it does in PhotoScan.

The PLY + overlay is exported from PhotoScan as a PLY file and a JPEG. Just like the OBJ is exported as an OBJ + JPEG. I assumed CC was loading the JPEG to give it the fuzzy texture, although maybe that information is encoded in the PLY? I can send an example if you like.

Re: Sharper photo overlay

Posted: Wed Nov 21, 2012 9:47 pm
by daniel
Yes, don't hesitate to send me the dataset.

From what I read, it seems that it's the responsibility of the user to load the JPG and manually 'associate' it with the mesh (there's no way to encode this in the PLY file).

Re: Sharper photo overlay

Posted: Thu Nov 22, 2012 5:59 pm
by mankoff
Here is a data set, PLY and OBJ. https://dl.dropbox.com/u/12453163/cc.zip

The PLY file has "comment TextureFile subglacial.jpg" and MeshLab auto-loads the JPEG with the PLY.

-k.

Re: Sharper photo overlay

Posted: Fri Nov 23, 2012 5:45 pm
by daniel
Ok, I've just added this functionality to the PLY loader.