Registration TLS Surveying

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geolux
Posts: 43
Joined: Thu Sep 03, 2015 5:06 pm

Registration TLS Surveying

Post by geolux »

Good morning Group
I'm testing the use of CC for register my ZF Scans without property ZF's Software.
There are differents way to do it.
But for a faster site survey the best is don't use (or little use) of topography mesures on targhet.
So, in this case I think that the better thingh, is put the scan position on site with the aim to use cloud to cloud orientation.
The Cloud to Cloud algoritm in CC work very well (with the correct setting) but I have a problem when I wont to orient my group of LS acquisitions, in a specific System Referent, using "align by pickin points pairs" command.
For do it, must I before merge the set of LS position, and them roto-traslate it on points pair? If it is the only way, This procedure in some case not is recommended because sometime is needed to leave separated the scan position, or in other coases the big number of scan position would make the merged file too big to do worked.
Have you other suggests?
Thank you
daniel
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Location: Grenoble, France
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Re: Registration TLS Surveying

Post by daniel »

The align too outputs a transformation matrix. Thanks to this, you can use the align tool on only one scan (if it's sufficient) or on a subsampled version of the merged cloud (if it's too big - with 'Edit > Subsample' - you can subsample the scans before merging them).

Eventually, copy the matrix from the console (when the Align tool has closed) and apply it to the original scans (with Edit > Apply transformation).
Daniel, CloudCompare admin
geolux
Posts: 43
Joined: Thu Sep 03, 2015 5:06 pm

Re: Registration TLS Surveying

Post by geolux »

Great Idea Daniel. Thank you
Only one other observation.
Take for example a big number of TLS dataset in a belt acquisition (street o similar), for obtain a good transformation matrix of a whole model (post cloud to cloud preregistration) I have to use some control point on the start of the street and some points on the end of the street, and not is advisable make this only on one LS position for avvoid drifting problems.
So, premise that make a merge and subsample (in some case is a good solution) is a long process and need a good hardware esources, is there other solution for grouping temporary the clouds?
I'm thinking e.g. to the possibility to enable some functions to the folder (in the left tree) containing the cloud, or adding a command to make a temporary group
daniel
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Joined: Wed Oct 13, 2010 7:34 am
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Re: Registration TLS Surveying

Post by daniel »

Nope, apart from subsampling or cutting the interesting parts of the scans before merging them, CC can't work with 'groups' for the alignment. This would be technically possible, but someone needs to change the code ;)
Daniel, CloudCompare admin
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