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Author Topic: Matched tie points in Sparse Cloud but no data in Dense Cloud  (Read 2948 times)

stihl

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Matched tie points in Sparse Cloud but no data in Dense Cloud
« on: October 29, 2014, 03:41:59 PM »
Hi,

I'm trying to create an Orthomosaïc. The sparse dense cloud after the alignment doesn't show any holes in the pointcloud.
However after running a medium dense point cloud step, holes in the dense cloud appear.

Can anyone explain why this would happen and how I can resolve it?

I was under the impression that Photoscan uses the sparse cloud to densify the point cloud. So how would holes appear in the Dense Pointcloud when the Sparse cloud doesn't show any holes?


Thanks!

« Last Edit: September 06, 2016, 12:18:12 AM by stihl »

Alexey Pasumansky

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Re: Matched tie points in Sparse Cloud but no data in Dense Cloud
« Reply #1 on: October 29, 2014, 03:48:30 PM »
Hello stihl,

PhotoScan generates dense cloud based on the merged depths maps estimated for each pair of overlapping images. In case there are too few matching points between a couple of images, they will not be counted as overlapping and depth map will not be generated. So probably for this area in the middle there's an overlap problem or the number of valid matching points between the photos corresponding to the area is below the threshold.
Best regards,
Alexey Pasumansky,
Agisoft LLC

stihl

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Re: Matched tie points in Sparse Cloud but no data in Dense Cloud
« Reply #2 on: October 29, 2014, 04:12:45 PM »
Hello Alexey,

Thank you for your reply.

The sparse cloud was generated with 500 tie points max per photo. I'll try again with 10.000 points per photo and see if this resolves it.

Alexey Pasumansky

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Re: Matched tie points in Sparse Cloud but no data in Dense Cloud
« Reply #3 on: October 29, 2014, 04:14:54 PM »
Hello stihl,

You can check the number of matching points between the images on the border of this hole using View Matches dialog.

Best regards,
Alexey Pasumansky,
Agisoft LLC