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Author Topic: Quality Improvements  (Read 7018 times)

scanlab.ca

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Quality Improvements
« on: September 12, 2012, 11:37:07 AM »
Hey guys,

I was wondering if there's any way to reduce blobby-ness without using masks.

Seems like this extra volume still appears even if I delete "all" extra points outside and inside the bounding box area after the alignment process.

That's actually one of the things that really throws me off, when everything looks clean and then boom after the heaviest and the longest process I get something, which can sometimes look completely different.

Or, let me put it another way, my expectation of the resulting mesh would so that the Geo conforms closer to the pre-selected PointCloud rather than the bounding box volume the mesh is in. Alot of times I feel like I'd rather have less than more.

I also need a little more explanation, if you can of what these P1, P2 parameters do in Preferences dialog. Even if its hard to explain just throw a few keywords at me that are a little bit less abstract. :)

Any hints? tips, tricks? ...money? :P


Cheers,
Rus
Best regards,

Ruslan Vasylev | Scanlab Photogrammetry
S: https://scanlab.ca | E: ruslan@scanlab.ca | T: 1 (778) 991-5157

Wishgranter

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Re: Quality Improvements
« Reply #1 on: September 12, 2012, 12:41:00 PM »
Hello... as far can be seen it is reconstructed on MEDIUM - HIGH, not ULTRA settings. then is only way to mask it. If you use Pshop ( CS5- CS6 ) ther is a very ussefull tool, press letter W and it shold be activated QUICK SELECTION TOOL ( not the MAGIC WAND TOOL !! ) the 4th tool from TOOL palette, move cursor with pressed LEFT mouse button over areas what need be masked, dont forget to INVERT mask.... Fastest it goes with custom shortcuts..

The problem is that ULTRA calculate every pixel, but High just every 2nd and Medium every 4th pixel of image...... Like you mask go outside of object and the pixels are counted..

Try it and let us know if that helped...
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Alexey Pasumansky

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Re: Quality Improvements
« Reply #2 on: September 12, 2012, 12:56:06 PM »
Hello Rus,

Looks like the photos of the object are made only from one side, so Smooth reconstruction method tries to reconstruct closed model and therefore additional geometry appears behind the object.
In general there could be three main options: reconstructing in Sharp (with no additional geometry), using masks for background, or taking photos from all sides of the object so PhotoScan could create closed model.

Please also note that geometry is reconstructed based on camera positions and not only by points in Sparse point cloud. So to refine camera positions Optimization should be run after some points are removed (currently only in Pro version).

Meaning of P1 and P2 parameters are described in the corresponding topic here: http://www.agisoft.ru/forum/index.php?topic=19.msg45#msg45
But in your case changing these parameters is not a solution.
Best regards,
Alexey Pasumansky,
Agisoft LLC

scanlab.ca

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Re: Quality Improvements
« Reply #3 on: September 13, 2012, 08:13:10 AM »
Hello... as far can be seen it is reconstructed on MEDIUM - HIGH, not ULTRA settings. then is only way to mask it. If you use Pshop ( CS5- CS6 ) ther is a very ussefull tool, press letter W and it shold be activated QUICK SELECTION TOOL ( not the MAGIC WAND TOOL !! ) the 4th tool from TOOL palette, move cursor with pressed LEFT mouse button over areas what need be masked, dont forget to INVERT mask.... Fastest it goes with custom shortcuts..

The problem is that ULTRA calculate every pixel, but High just every 2nd and Medium every 4th pixel of image...... Like you mask go outside of object and the pixels are counted..

Try it and let us know if that helped...

Thanks Wishgranter,

Yeah, i did have a hunch it was because of the UltraHigh settings, but still, my expectation was that this oversampling would be avoided by getting rid of any extra points floating around.
Would be nice to see an improvement in this area maybe in the next update, just so the results are a little bit more predictable, cause it does take nights to see these results.


Hello Rus,

Looks like the photos of the object are made only from one side, so Smooth reconstruction method tries to reconstruct closed model and therefore additional geometry appears behind the object.
In general there could be three main options: reconstructing in Sharp (with no additional geometry), using masks for background, or taking photos from all sides of the object so PhotoScan could create closed model.

Please also note that geometry is reconstructed based on camera positions and not only by points in Sparse point cloud. So to refine camera positions Optimization should be run after some points are removed (currently only in Pro version).

Meaning of P1 and P2 parameters are described in the corresponding topic here: http://www.agisoft.ru/forum/index.php?topic=19.msg45#msg45
But in your case changing these parameters is not a solution.

Thanks for the info Alexey,

I was a little too lazy and didn't capture all sides of the subject, since it was more or less a test. But, sometimes it is hard to get all the details or angles in a non-constrained environment. Maybe there could be an option to tell PS a degree of tolerance for these puffy, undersampled areas?

And.. by the way, I did look at that P1P2 post previously, but it still did not explain much. :S
I mean like, what units these parameters are in?
« Last Edit: September 13, 2012, 08:15:35 AM by edgeArchitect »
Best regards,

Ruslan Vasylev | Scanlab Photogrammetry
S: https://scanlab.ca | E: ruslan@scanlab.ca | T: 1 (778) 991-5157

Alexey Pasumansky

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Re: Quality Improvements
« Reply #4 on: September 13, 2012, 03:21:52 PM »
Hello Ruslan,

We plan to remove P1 and P2 parameters from Preferences window and to add instead of them several presets that would be more clear for users. Changing such presets (P1, P2 parameters) will produce more detailed or smoother depth maps, for example.
Best regards,
Alexey Pasumansky,
Agisoft LLC