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Author Topic: Build Depth Maps Without Creating Dense Cloud?  (Read 4763 times)

StevenF

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Build Depth Maps Without Creating Dense Cloud?
« on: November 18, 2014, 02:02:32 AM »
Is it possible to create and save depth maps from the Build Dense Cloud process without going on to construct a dense cloud from the depth maps?
This post references a "Build Depth Map" option in the photo pane context menu:
http://www.agisoft.com/forum/index.php?topic=748.msg3502#msg3502
I can't seem to find this option. Has it been removed?

The reason I ask is that my machine seems to be capable of "Reconstructing Geometry" (aka building depth maps) during the Build Dense Cloud process, but then it runs out of memory when it actually goes to make a point cloud from the depth maps. I'm running on linux so the OOM killer kills the process when "accumulating data..." for too many cameras.

If I could build the depth maps separately then I could later construct dense clouds in smaller tiles to avoid running out of memory. This would be much faster than tiling the whole build dense cloud process (i.e. reconstructing geometry + constructing point cloud). I tested this out.

I tried tiling the whole Build Dense Cloud with a small data set on medium quality and it took about 30 minutes. If I start the Build Dense cloud process for the entire project area and cancel it after depth maps have been created then I can reuse the depth maps to tile the dense cloud construction step. This method only takes about 7 minutes, but I have to cancel the Build Dense Cloud process right after it's done constructing depth maps or I risk crashing Photoscan and losing everything. This could be days worth of processing for large projects!

StevenF

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Re: Build Depth Maps Without Creating Dense Cloud?
« Reply #1 on: November 18, 2014, 07:01:30 AM »
Nevermind.
I'm running out of memory during Load Photos. I tried the approach of building depth maps then tiling the dense cloud production on a smaller project area. It turns out the size of my test area was in the sweet spot where I could load photos, reconstruct geometry and only run out of memory during dense cloud construction. I thought the approach would scale up but quickly found out that it didn't. I'll have to run the whole process in small tiles.

Alexey Pasumansky

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Re: Build Depth Maps Without Creating Dense Cloud?
« Reply #2 on: November 18, 2014, 10:48:45 AM »
Hello Steven,

What is amount of memory on your computer and the size/resolution of images used?
Best regards,
Alexey Pasumansky,
Agisoft LLC

StevenF

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Re: Build Depth Maps Without Creating Dense Cloud?
« Reply #3 on: November 18, 2014, 08:10:18 PM »
I have 48gb of RAM and I'm working with 944 images that are 7680x13824. So I'm going to have tile the whole process. It will probably take quite awhile, but it works.

barrubba

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Re: Build Depth Maps Without Creating Dense Cloud?
« Reply #4 on: August 21, 2017, 11:26:24 PM »
Hi StevenF, i'm on the same situation..not enough ram and big project.
Can you confirm its a valid trick to save time?
thanks