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A Very Large Corner

The place for questions, problems, comments and tips regarding the camera calibration.

A Very Large Corner

Postby treleau » Tue Mar 30, 2010 12:27 pm

I propose a very planar corner system.

It's made with 19 mm melamine agglomerate board of 120 cm by 80 cm
and 1.5 mm thickness iron rail of 32 mm by 45 mm by 2.00 m,
find in Brico Dépôt http://www.bricodepot.fr/rennes/node/469848

It's very rigid and strong.

It's easy to adapt the dimensions for your project.

VLC5.jpg
back of installation
VLC4.jpg
assembly
VLC3.jpg
assembly detail
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Re: A Very Large Corner

Postby treleau » Tue Mar 30, 2010 12:49 pm

an other view of my corner system.

The calibration points are glued individually (scale : 100 mm).
VLC6.jpg
System for right angle adjustment.
VLC2.jpg
calibrate points are glued with re-positionable spray mount.
test new corner.jpg
first analyse
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Re: A Very Large Corner

Postby joecnc2006 » Thu Apr 01, 2010 3:48 am

Looks interesting, How did you layout the correct dot placement If you could show your technique? I think this would work well for my next project.
Joe

David-Laserscanner Professional Edition, Logitech Pro 9000 Webcam, LC532-5-3-F(16x65)

www.joescnc.com
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Re: A Very Large Corner

Postby treleau » Thu Apr 01, 2010 8:49 am

Hello Joecnc
Thanks for your interest.

I have positioned the calibration's points with a vertical line.
mesure des points.jpg

For horizontal position, I measure directly with a metre.
colage des points.jpg

For help me, I draw with Inkscapehttp://www.inkscape.org/?lang=fr a personal calibration points with light grey cross.
david pannel.jpg

Through this technique, the board is not overlay with paper and the analyse is more fine. 8)
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Re: A Very Large Corner

Postby treleau » Thu Apr 01, 2010 12:08 pm

If you doubt of the interest of a large calibration panel...


statuedejf2.jpg
Luxblend renderer



For memory, remember my problems with a small panel . :wink: http://www.david-laserscanner.com/forum/viewtopic.php?f=2&t=1680
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Re: A Very Large Corner

Postby WalterMo » Thu Apr 01, 2010 3:47 pm

Hi treleau,
Perfect scan of a perfect body. :wink:
How tall is the statue and what was the scale length on your large calibration corner?

Yes, often it's better to use a large corner than a small one and align a lot of single scans together. Specially when it is reasonable and the object hasn't so much details. But nice details, like in this case.

And it was a good idea to glue the points directly onto the walls. I remind to Bruno, who had no other chance as to glue the points on the ground and to stick them on the wall behind it:
viewtopic.php?p=4247#p4247

Walter

Edit: Scale was 100mm, just noticed.
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Re: A Very Large Corner

Postby treleau » Thu Apr 01, 2010 6:24 pm

Hi Walter,

thanks for compliments, the statue measuring 90 cm by 20 cm by 15 cm.
I analyse it with four level of six scan and I scan the head separately with near distance's camera.
And, I join head, with body, in ZBrush.
The back-ground are scanning also in the corner with a piece of cloth.
Yes, the scale was 100 mm it's more easy to count (for me). :lol:

Treleau
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Re: A Very Large Corner

Postby thierr_cnc » Thu Apr 01, 2010 6:57 pm

Brico dépot Rennes...

Perso je vais à celui de st Brieuc

world is small !!

Thierry
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Re: A Very Large Corner

Postby treleau » Thu Apr 01, 2010 7:15 pm

En effet :D

Je reprendrai contact pour vous parler de mon projet de CNC.

kenavo Thierry

Treleau
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Re: A Very Large Corner

Postby WalterMo » Sat Apr 03, 2010 5:59 pm

Hello Treleau,
You told me that your scale was 100mm. But you are using the new kind of printouts with 70 dots.
That means the scale is to measure over 4 dots. In your case if you don't want to use absolute data coming out from DAVID it's not important. But if you want to make a 1:1 copy of the statue by a CNC machine or a 3D plotter you must tell DAVID „400mm“.

Walter
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Re: A Very Large Corner

Postby treleau » Tue Apr 20, 2010 8:46 am

Hello Walter,
thanks to put me in the right way.
Stupidly, I believed the scale was the space between two points. :oops:
Treleau
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Re: A Very Large Corner

Postby eliscio » Wed Mar 30, 2011 3:55 pm

I was just thinking...what is the ratio of the inner diameter to outer diameter of the 'rings" in the calibration panels?

It appears to me that the black dots and the white centers of the rings have the same diameter. What about the outer diameters of the rings?

Thanks,

Eugene
www.ai2-3d.com
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Re: A Very Large Corner

Postby MagWeb » Wed Mar 30, 2011 4:21 pm

Hi,

the ratio of inner, white marker and outer black ring seems not to be important. I even did those white dots bigger than the simple black markers (to make them easier to mill on my CNC)

Meanwhile I found a jpeg I successfully used
Attachments
Calibpoints_gross.jpg
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Re: A Very Large Corner

Postby Eros » Tue Oct 23, 2012 1:08 pm

Hi,
I´m a new user of David Laserscanner and I have a cuestion, If I make a corner calibration to what extent these points may affect the accuracy? On latest version,there are not panels calibration in DIN-A1 format?
Thank you very much.
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Re: A Very Large Corner

Postby WalterMo » Tue Oct 23, 2012 3:07 pm

Please read this site:
viewtopic.php?f=1&t=2316&p=19338&hilit

E.g. with the mentioned free software „Posterazor“ you can build panels of some A4 sheets as big as you like. And since DAVID 3.1 the A4 calibration pattern also come as *.png files. That format fits to Posterazor. :)

Of course if you have an A1 printer at hand it should be no problem to print the left and the right A4 calibration sheets with that device. The calibration scale is automatically also printed on these sheets and its length must be „told“ to DAVID during the camera calibration procedure.
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