Sphere based registration is not accurate, I need some help

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Augusto 3D
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Re: Sphere based registration is not accurate, I need some help

Post by Augusto 3D »

The issue we are having is that we get a better registration with c2c and when you look at the spheres they dont look round...
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Leandre Robitaille
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Re: Sphere based registration is not accurate, I need some help

Post by Leandre Robitaille »

Augusto,

...Have you done an accuracy check on your scanner? We can be blaming people sphere but until you post the results of that check nobody can say if its either the spheres or your scanner.

Set up a network of spheres (try at least 6)
Scan them with the Focus.
Move the Focus over a few feet and rotate it 180 degrees.
Scan the target network again.
Register the two sets of scans together. Depending on the laser scanner that was used, the point distance should not exceed the following limits:
Focus 3D / X / XHDR: 4mm
Focus M70: 6mm
Focus S70/S150/S350/Premium: 2mm
Augusto 3D
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Re: Sphere based registration is not accurate, I need some help

Post by Augusto 3D »

Im not blaming koppa, I have a suspicion that it could be our scanner.

I haven't done what you mentioned, but will do this asap.

I also emailed support (faro) asking if we should do an onsite comp. They never replied. Do you think we should?

Tell me a little more about the control network. How far from the scanner etc. I am also going to do this with our X7 to put this to rest.
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tadol
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Re: Sphere based registration is not accurate, I need some help

Post by tadol »

I didn’t think anyone was blaming my spheres - but, it was a reminder that no matter how much we trust our sources, brands, or processes, its the smarter person who double checks everything, and never takes anything for granted. It was the perfect excuse for me to double check all my parts and to validate everything was what I expected it to be - plus, it was an excuse to buy a new indicator - ;-) -

I will never claim that spheres are the ultimate registration accessory - but they are very good tools and can make achieving excellent results easier in many situations. But they are just a tool, and even the best tools work better with practice and experience. Unfortunately, I can only test and validate my product, and don’t have the experience or expertise to evaluate the many other hardware and software (and environmental) issues that might be involved, and appreciate the collective knowledge and experience of this forum -

Thanks! Tad
http://www.KoppaTargets.com
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Justin Richards
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Re: Sphere based registration is not accurate, I need some help

Post by Justin Richards »

Augusto 3D wrote: Sun Jul 03, 2022 3:18 am Im not blaming koppa, I have a suspicion that it could be our scanner.

I haven't done what you mentioned, but will do this asap.

I also emailed support (faro) asking if we should do an onsite comp. They never replied. Do you think we should?

Tell me a little more about the control network. How far from the scanner etc. I am also going to do this with our X7 to put this to rest.
Faro doesn't really give much more detail but I would go about 5' and 10' from the first scan and compare both. It will be pretty obvious if something is wrong. For the onsite compensation, we do them every time a scanner comes back from a rental, it's a good indicator of who takes care of the scanners and who doesn't for scanners we didn't ship to them. If you haven't done it before, it can take a little practice to get it to work the first time. It's okay to have the last sheet on the floor if needed.
https://knowledge.faro.com/Hardware/3D_ ... _the_Focus
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Re: Sphere based registration is not accurate, I need some help

Post by nyterydur »

Augusto 3D wrote: Mon Jun 20, 2022 4:56 pm
I have a question, if I set anti-correspondence for some spheres and I start to get scans failing, how do I associate them again?
If you accidentally set too many anti-correspondences and now the scan cluster fails, you simply right click the cluster thats failing and select:
Operations > Correspondences > Delete Correspondences then a little window pops up allowing you to select which correspondences to delete either :
1. User Forced
2. System Found
3. Anti-Correspondences

By selecting #3 it will remove any and all anti-correspondences that you set within that cluster.
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Re: Sphere based registration is not accurate, I need some help

Post by VXGrid »

Augusto 3D wrote: Sun Jul 03, 2022 3:18 am Im not blaming koppa, I have a suspicion that it could be our scanner.

I haven't done what you mentioned, but will do this asap.

I also emailed support (faro) asking if we should do an onsite comp. They never replied. Do you think we should?

Tell me a little more about the control network. How far from the scanner etc. I am also going to do this with our X7 to put this to rest.
If you like to you can send these test scans over to me (if you have the same issue again in Scene that the c2c is much more accurate than the feature based registration),
then I can double check them with another software package, so you can change one variable in whom to blame and perhaps find out ;)
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