PS for landscape sweeps?

[maddin]

I am trying to use PhotoScan to generate high resolution landscape sweeps, similar to a panorama.
So instead of flying high and pointing the camera downwards, I would like to flow lower and tilt the camera more towards the horizon during flight.

The overall goal is to create a high resolution landscape view by 'stitching' together the individual camera pictures, using a 3D surface model generated by PhotoScan.

So far, I have only gotten mediocre results from the 'Build Geometry' step (too smooth (Arbitrary) or too noisy (heightfield) and generally too many artifacts when textured) and would be interested in any advice, comments, recommendations.

Also, I need much higher texture resolution than what I seem to be able to get (in the order of 50k * 50k). Any ideas how to achieve that?

Thanks!
Martin

[maddin]

I am trying to use PhotoScan to generate high resolution landscape sweeps, similar to a panorama.
So instead of flying high and pointing the camera downwards, I would like to fly lower and tilt the camera more towards the horizon during flight.

The overall goal is to create a high resolution landscape view by 'stitching' together the individual camera pictures, using a 3D surface model generated by PhotoScan.

So far, I have only gotten mediocre results from the 'Build Geometry' step (too smooth (Arbitrary) or too noisy (heightfield) and generally too many artifacts when textured) and would be interested in any advice, comments, recommendations.

Also, I need much higher texture resolution than what I seem to be able to get (in the order of 50k * 50k). Any ideas how to achieve that?

Thanks!
Martin

Attached is a screenshot of what I have at the moment, and while it looks somewhat promising, I am not able to get a well-textured result out of it; there simply are too many incorrect projections onto the somewhat imprecise surface, causing clearly visible artifacts.

I'd appreciate any suggestions, thanks a lot!
Martin

[Wishgranter]

Use ARBITRARY settings in mesh generation and report back 

[chadfx]

He mentioned trying Arbitrary already, but it was 'too smooth'. But that seems strange to me...I would think Arbitrary should work fine. Maybe set the build resolution to a higher level? Mosaic texturing should also work well afterwards, no?

[maddin]

OK, 12 GB is not enough for this scene using Arbitrary / Sharp / High / 0 / 2

[maddin]

I now have completed a reconstruction at Arbitrary / Sharp / Medium / 0 / 0, see attached screenshot. This produces 180 mio. faces and a .psz file of 2.18 GB!

While the detail looks great (note: no texture built yet), I cannot use this due to the thousands of gaps between the individual chunks of geometry. I need a closed surface as I need a continuous image in the end.

Martin

[chadfx]

That certainly looks much better.

Have you tried using the 1.0 prerelease version? It has some nicer methods for building smooth and interpolated geometry, and you can edit the dense point cloud to remove unwanted parts before the geometry is built.

Although with so many 'unseen' areas in the photos, I'm not sure if you will ever get a truly representative build...a lot of those gaps are quite large.

[maddin]

Have you tried using the 1.0 prerelease version? It has some nicer methods for building smooth and interpolated geometry, and you can edit the dense point cloud to remove unwanted parts before the geometry is built.

No, I was somewhat hesitant to run a beta as beginner. Also the fact that I cannot open files created with the 1.0 version in older (regular) versions kept me from using it. Will we be able to use 1.0 once it is final with our old licenses?

What options for 1.0 would you recommend, and where should I be looking for those nicer methods?

Although with so many 'unseen' areas in the photos, I'm not sure if you will ever get a truly representative build...a lot of those gaps are quite large.

Why do you think they are unseen? I haven't looked closely yet but I would believe we saw most of the old town while flying by...

Thanks!
Martin

[maddin]

And here is (a part of) the same scene, now using Arbitrary / Smooth / Medium / 0 / 0
As you can see, it introduces some funny smooth connections between the roofs, or around the church tower.

So, yes, Arbitrary / Sharp would be great, but: I cannot run it at High quality, and at Medium, it creates too many holes where it really should not have to (e.g. on the little market place in the front center).

I will now try v1.0 just to see what happens.

Martin

[chadfx]

Hi Martin, the betas are generally quite stable, and you can also use 'Save As...' and save the project files back into the .9.x file format for backwards compatibility. If you look at the pre-release thread, you can find out about most of the new features:

http://www.agisoft.ru/forum/index.php?topic=1476.0

When you build the mesh after the dense point cloud is created (it used to be just Build Geometry, but now it is two phases), there is an advanced option to control the interpolation. The default (enabled) mode will try to fill in most minor gaps, but not fill in the larger holes that sometimes led to weird issues and ugly large chunks. I have a feeling this is exactly what you will want to try out in the new version. You will likely wind up with some gaps, but better to fill those in on your own than have odd lumpy geometry.

The unseen areas I would imagine are just parts of the environment that are not showing up in enough images (usually 3 minimum) for Photoscan to work with.

Cheers, -C

[maddin]

Thanks, I will try 1.0 now - can I have both installed at the same time?
Edit: No, one needs to uninstall 0.9.1 first.

Some parts that are missing in the sharp reconstruction are definitely seen on multiple images, but maybe their exposure is off or there is a leafless tree in front... do we have any further control on how PS creates the dense data besides High/Medium/Low?

Martin