Fail to align faro scans with photos

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Manolis

• November 05, 2018 16:12

Hi all,

I've seen a tutorial about aligning a lidar scan with drone photos to create an amazing model. Now, I have a lidar scan of an interior of a building and 170 photos of some details, such as the elevator entrances and stairs. Since the floor is low textured with very few features detected, I need Faro scan to provide the correct geometry information and photos to add some details to the scan.

My pipeline is:

1. align all the photos and export as one component, 'photos'.

2. align the faro scan data.

3. import the photo component to the Faro project, then click 'align'. In the align setting, I set both 'force component rematch' and 'merge component only' as true.

However, it comes out still two separate components, one is faro data, and the other is 'photos'. I've tried to add control points, but it doesn't work. These two components still cannot be aligned.

Is it because the data is not sufficient? Should I add more photos or take more lidar scans? 

Or there are other ways to help me align these two kinds of data?

Best regards,

Manolis

 

 

 

 

 

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  Zuzana Durickova 2

  • November 06, 2018 20:15

  Hello Manolis,

  did you import your laser scan with color? In most cases this is necessary for correct alignment with images. You can also try to raise the number of detected and preselector features in the alignment settings or add more control points in common areas. 

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  Manolis

  • November 07, 2018 08:37

  Hi Zuzana,

  Thanks for your reply. 

  The laser scan and photos were taken in different lighting environments and the photo's lighting and color are way better than that of Faro scan. Perhaps, that's the reason why I cannot align them.

  Thus, I'm thinking about:

  1. add more photos and control points;

  2. or just align all the photos and compute the transformation from photos to the scan mesh, so as to generate a texture map for the laser scan with photos' color.

  Obviously, the later one is more time-consuming. Hopefully, I'll succeed with the first method ;)

  Thanks again for your suggestions.

  Manolis

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  ValerioPaolux

  • November 09, 2018 23:29

  Hi Manolis,
  
  I combine Faro scans and images all the time. If your scans are colored you should not need CPs to merge all. However, you may need to set  "merge components only=false" and if that is not sufficient you may want to try increasing the max feature per image count to 40k or 80k. Control Points should be your last resource, but even then a mere 3 points in 4 images should be enough to give you 1 component.
  Cheers,
  
  Valerio

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  Manolis

  • November 11, 2018 07:21

  Hi Valerio,

  It works!

  There is one component consisting of faro scans aligned with photos, even though some scans and photos go to other components : |.

  Thanks for your suggestions! I'll try to add more scans and photos to increase the quality.

  Best Wishes,

  Manolis

  
   

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