How could I export the sparse point cloud (only after aligning images) which is displayed in the viewer? I have already tried the export command in the alighment section

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1

I want to export the point cloud which is displayed in the viewer after the image alignment. I believe this is also the result of SFM algorithm in the traditional MVS pipeline.

 

However, I got a very noising point cloud when I export it through “alignment” -> “export” -> “point cloud”. And this is different from the point cloud I saw in the RC viewer.

I do search in the forum and found some relevant poses, but I do not get the answer to my question. Could anyone give me some hints about that?

 

Also, I am curious about noise points in the sparse point cloud. The reprojected error of these points might be higher than the threshold. Why didn’t RC filter out these points in the SFM pipeline?

 

 

2

Hi Lin Lin,

this is quite unusual.

Do you want to export just sparse point cloud?

Can you check, how many points do you have in the aligned component?

And what do you have in settings for Max points to display?

Also, can you try Inspection tool for your alignment: https://support.capturingreality.com/hc/en-us/community/posts/4409723827986-Inspection-Tool

3

Yes, I just want to export the sparse point cloud for research purposes. RC shows that there are 4,406,282 points in the component, but I got 3,539,746 points in the output ply file. The “max displayed point number” is 10,000,000 in the global settings.

 

 

 

That is pretty common during our previous experience with RC. So we try to figure out the reason now. The reconstruction works well though.

 

Also, our RC version is 1.2.0.16813, if this is useful.

4

Also, the inspection tool shows that all the points are good? I am not sure since I am not familiar with this tool, I just use the default settings.

5

Hi,

can you try to change these values for more optimal values:

10 000 and 40 000 are good enough for most cases.

More about Inspection tool you can find in Help, also, try to change the settings to see the points.

Can you try to download newer version (17385) from our site?

6

I reset the alignment to the default setting, but I got the same result. 

 

I noticed that the viewer says it shows the “tie points”. Are the “tie points” the same as the exported “sparse point cloud”? 

7

Tie points are points founded on the images and these are used for image alignment. They should be the same as points from sparse point cloud in 3D.

Also, can you change the Position accuracy to a smaller value? 100 m is not useful in this case.

Is it possible to share your dataset with us for some tests?