Page 1 of 2

Control Cleaning noise a from a free-shaped cloud

Posted: Wed May 08, 2019 6:49 pm
by Rzok
Hi, i tried to used a noice reduction filter, and set the noise filter with radius 0.010 why it random cleaning a points from the same cloud. I mean i used this many times with the same parameters at orignal cloud and the number and the points was diffrent. How this tool actually works? Image

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Wed May 08, 2019 6:51 pm
by Rzok
other screen of cloud Image

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Wed May 08, 2019 9:43 pm
by daniel
Can you detail your exact workflow?

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Thu May 09, 2019 1:35 pm
by Rzok
i imported a original data cloud from CMM and a i used a Noise reduction filter with parameters radius sphere 0.01 mm and thats all.

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Thu May 09, 2019 1:36 pm
by Rzok
The problem is when i import a same cloud not the same points are hidden by the same parameters u understand?

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Fri May 10, 2019 1:14 pm
by daniel
The exact same cloud?

And are you referring to the 'SOR filter' or the more complex 'Noise filter'? (I guess it's the second one, but I prefer to double check)

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Fri May 10, 2019 4:12 pm
by Rzok
yes the exact same cloud and i used a noise filter not sor filter

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Sat May 11, 2019 2:15 pm
by daniel
Ok, so I was able to reproduce this effect on my side... But I still don't know why it's not perfectly reproducible yet... I'll have to investigate more.

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Thu May 16, 2019 10:18 am
by Rzok
Hi Daniel again, can you help me explaining this noise filter? Since i got my points cloud i need to reduce the noises with the control way, and uhm my cloud have 625 points and my professor says that error of CMM its 5 um and the roughness of surface is 10 um and according to this informations Professor says the number of the points detected as a noises should be like a 30 +/-. But the program deleting about 8 to 10 points. How exactly set the parameters to get a cloud filtered like that? Im doing this to get my master's degree and need help :<

Re: Control Cleaning noise a from a free-shaped cloud

Posted: Thu May 16, 2019 7:12 pm
by daniel
Well, first, this tool is clearly not meant to be used on such a low density cloud.

It's principle is to fit a local plane by considering the neighbors of each point (https://www.cloudcompare.org/doc/wiki/i ... ise_filter). The parameters at the top of the dialog are used to define the 'neighbors'.

Then the distance between the plane and the central point is compared to the distance of the other points to the plane. You can decide to clean the points based on this distance ('Absolute') or based on the average distance plus a given number of times the standard deviation (1 by default).