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Author Topic: Dense Point Cloud generation // far slower in Metashape?  (Read 6560 times)

toxicmag

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Dense Point Cloud generation // far slower in Metashape?
« on: January 10, 2019, 01:10:50 PM »
Dear all,

i finished a job in Photoscan last December and was curious if i could get even better results now in Metashape.

It's ~1300 cameras with 9MB each and i need the dense cloud as result. Nothing else.  ;)
Alignment in high was fast and got all cameras well. Dense cloud generation was set to high as well, but it definetely takes too long.  :(

Was the dense cloud generation set to a lower priority level in developing Metashape? Everyone speaks about depth maps now which might be great for texturing but not for the survey industry.


GPU is on (GTX 980Ti)
128 GB RAM
i7 5820K @3.3GHz


Thx for your feedback.
#multirotor #VTOL #Trinity #Quantum-Systems #a6000 #a7R #RedEdge #ALTUM #RX1II

Alexey Pasumansky

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #1 on: January 10, 2019, 01:54:57 PM »
Hello toxicmag,

Are you using the latest Metashape release version? And do you have the processing logs or at least the timing information from the Chunk Info dialog for 1.4 and 1.5 processing?

Usually long dense cloud filtering process is related to the excessive overlap. If it is the case, the processing time can be reduced by limiting the number of pairs for each camera to be estimating during filtering. It can be done by creating main/dense_cloud_max_neighbors tweak and setting its value to 60, for example.
Best regards,
Alexey Pasumansky,
Agisoft LLC

toxicmag

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #2 on: January 10, 2019, 07:43:32 PM »
Are you using the latest Metashape release version?

Yes - latest. Always.

Quote
And do you have the processing logs or at least the timing information from the Chunk Info dialog for 1.4 and 1.5 processing?
Not at the very moment - the machine is busy, but i guess i will cancel that now...

Quote
Usually long dense cloud filtering process is related to the excessive overlap. If it is the case, the processing time can be reduced by limiting the number of pairs for each camera to be estimating during filtering. It can be done by creating main/dense_cloud_max_neighbors tweak and setting its value to 60, for example.
This is the case. Right. High overlap in flying AND also halv of the dataset are obligue photos. I need high precision in the pointcloud to match it against terrestrial scanning.


I guess i will reduce it to "medium" and maybe also try your advice with the neighbours

Greetings

Alex
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toxicmag

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #3 on: February 01, 2019, 09:16:54 AM »
Dear Alexey,

The processing took a while and now the model looks awesome.  :D
But one full week with quite a nice workstation is far too long for just the “generating densecloud“ step.

Do you and the team plan to provide GPU support for this step some day? The question comes up because i would like to add another graphic card into the system but it would not help in this case.

Thx a lot.

Alex
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Liesenfeld-Vermessung

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #4 on: February 01, 2019, 02:30:54 PM »
+1

I would also love to see an increase of the performance .

saduka

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #5 on: April 16, 2019, 08:26:40 PM »
+1

also due to certain reasons, have the chance to revisit the old project data.
dense cloud computation much much slower than before

dnb118

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #6 on: April 17, 2019, 04:00:51 AM »
Hello toxicmag,

Are you using the latest Metashape release version? And do you have the processing logs or at least the timing information from the Chunk Info dialog for 1.4 and 1.5 processing?

Usually long dense cloud filtering process is related to the excessive overlap. If it is the case, the processing time can be reduced by limiting the number of pairs for each camera to be estimating during filtering. It can be done by creating main/dense_cloud_max_neighbors tweak and setting its value to 60, for example.

i apologize for being a noob... can you enlighten me as to how to do this? thanks

saduka

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #7 on: April 17, 2019, 10:42:39 AM »
Hello toxicmag,

Are you using the latest Metashape release version? And do you have the processing logs or at least the timing information from the Chunk Info dialog for 1.4 and 1.5 processing?

Usually long dense cloud filtering process is related to the excessive overlap. If it is the case, the processing time can be reduced by limiting the number of pairs for each camera to be estimating during filtering. It can be done by creating main/dense_cloud_max_neighbors tweak and setting its value to 60, for example.

i apologize for being a noob... can you enlighten me as to how to do this? thanks

if you are using python, just add a max_neighbors variable in the function
Code: [Select]
chunk.buildDepthMaps(quality=Metashape.Quality.HighQuality,
                    filter=Metashape.FilterMode.MildFiltering,
                    reuse_depth=True,
                    max_neighbors=50)
doc.save()
chunk.buildDenseCloud(point_colors=False,keep_depth=True,max_neighbors=50) 
doc.save()       

Alexey Pasumansky

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #8 on: April 17, 2019, 01:32:43 PM »
Both in Standard and Professional editions of Metashape it is possible to create a new Tweak (via Advanced preferences tab -> Tweaks button) with the following name:
Code: [Select]
main/dense_cloud_max_neighborsThen set it's value to 60, for example. The default value is -1, which means that there's no limit.
Best regards,
Alexey Pasumansky,
Agisoft LLC

dyoung

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #9 on: June 18, 2019, 06:50:35 PM »
Hi all -- I am encountering this issue too. I have a dataset of 2300 photos with 95% front and side overlap (so there are up to 400 photos of any given point on the ground). It's great to know about the max_neighbors tweak.

I am wondering: is reducing dense_cloud_max_neighbors effectively the same as reducing the overlap in my dataset? That is, is it a waste for me to collect images with 95% overlap? Would I be just as well off collecting images with, say, 90% overlap? Or is the additional overlap useful for stages other than the second stage of dense point cloud generation? I collected images with high overlap because I want detailed rendering of the trees in my study sites.

Thanks!
Derek

Alexey Pasumansky

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #10 on: June 18, 2019, 08:42:05 PM »
Hello Derek,

Using the tweak is not the same as disabling/removing the cameras from the image set. For example, the depth maps would be generated considering all the possible neighbors (may be useful for the depth maps based mesh reconstruction).

In the version 1.5.3 build 8432 we have set the default value for main/dense_cloud_max_neighbors parameter equal to 100, so it should considerably reduce the processing time for the dataset with the excessive overlap, but shouldn't affect the quality of the results for the common datasets.
Best regards,
Alexey Pasumansky,
Agisoft LLC

dyoung

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Re: Dense Point Cloud generation // far slower in Metashape?
« Reply #11 on: October 14, 2019, 10:54:09 PM »
Thank you! That makes sense. Sorry I was so slow to thank you.