Scans not accurate enough

Questions, problems, comments and tips regarding the 3d scanning process.

Scans not accurate enough

Postby Stephan3D » Sun Feb 01, 2009 6:00 pm

Hello,
I have some problemne with "shape fusion."
I think my scans are not accurate enough, but why?
The upper half is ok, but down the way it is inaccurate.
Even at 360 degrees scans do not match the first to last.
I've tested everything:
Rear exactly 90 degrees (+ -0.5 degrees)
Calibration model no waves
Shape Fusion: global, fine, manual, etc.
Where is my error?
Or what do I need to set parameters for david?

greetings, stephan

Here are a few pictures:
Attachments
t1.jpg
t2.jpg
t3.jpg
PC: Intel I7, 3,2GHz, 6GB Ram, Geforce GT550Ti, Win7 64
Cam: Logitech QuickCam Pro 9000
Laser: LC650-5-5-F(14x45)-NT,Wellenlänge: 650nm,Opt Leistung: 5mW
Beamer: Acer C20
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Location: Germany

Re: Scans not accurate enough

Postby MagWeb » Sun Feb 01, 2009 6:23 pm

Hi,

possible reasons:
- too low intersectionangle (also if DAVID doesn´t warn yet)
- the detected line left and right is´nt straight (for you fixed the pattern wavy or the edge(s) of the detectionboards are visible) or rather short (maybe caused by the black dots)
- The pattern isn´t fixed precisly ( somehow twisted, one side too high, or the distance to zero at scale 60=40mm)

I prefere to use a 4:3 pattern as posted here http://www.david-laserscanner.com/forum/viewtopic.php?f=1&t=242,

You could switch off the backgroundfilter and scan the empty corner. the result should perfectly fit to the grid in the 3D viewhttp://www.david-laserscanner.com/forum/viewtopic.php?f=1&t=398 Since 2.0 you find the Background filter factor in the advanced settings. To disable it set its value to -1 (negative).

Gunter
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Re: Scans not accurate enough

Postby Stephan3D » Thu Feb 05, 2009 9:21 pm

Hello,
I have found my problem.
If the object is too far from the background stands out, I have distortions.
I can not be too close to my background, because my background touches the object, if it is on my turntable revolves.
A larger calibration pattern I want to avoid, since I then lose the details.
Is that my solution? (see Picture of hal)
How does that work exactly, how I calibrate?

I have just moved the calibration model, but that does not work. (see my picture)

stephan
Attachments
work in progress.jpg
Picture of hal
test.jpg
My test, not work.
PC: Intel I7, 3,2GHz, 6GB Ram, Geforce GT550Ti, Win7 64
Cam: Logitech QuickCam Pro 9000
Laser: LC650-5-5-F(14x45)-NT,Wellenlänge: 650nm,Opt Leistung: 5mW
Beamer: Acer C20
Stephan3D
 
Posts: 45
Joined: Sun Jan 18, 2009 11:24 am
Location: Germany

Test

Postby Stephan3D » Thu Feb 05, 2009 9:49 pm

Hello again,
this is my first test :D

You sees the problems in my shoes because of distortions.
I also have a few problems with the texture transitions.

stephan
Attachments
Zwerg.jpg
Zwerg test
PC: Intel I7, 3,2GHz, 6GB Ram, Geforce GT550Ti, Win7 64
Cam: Logitech QuickCam Pro 9000
Laser: LC650-5-5-F(14x45)-NT,Wellenlänge: 650nm,Opt Leistung: 5mW
Beamer: Acer C20
Stephan3D
 
Posts: 45
Joined: Sun Jan 18, 2009 11:24 am
Location: Germany

Re: Scans not accurate enough

Postby MagWeb » Thu Feb 05, 2009 10:10 pm

Hi,

hope you are using the 60mm scaled printout:
Simply change the values in the calibpoits.dat file.


Open the file (in the DAVID folder) with the Win Editor.
You see coordinates of the points.
Each line is one point.
1.column: Pointnumber (do not change)
2.column: x-value
3.column: y-value
4.column: z-value

Leave column 1 and 3 untouched.
In 2. and 4.:Add the distance X, you moved the pattern from the center(edge of your paper to center) in millimeter to all the values of the that are NOT equal zero
(keep the format)

If you use another scaled printout:
E.g.: Printout scaled at 30 (60 scaled means 1:1)
60/30=2 so you´ve to
add 2X
Printout scaled at 20
60/20=3 so you´ve to
add 3X

Save your modification
Restart DAVID and calibrate.

Gunter
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A big dwarf.

Postby hal » Sat Feb 07, 2009 1:33 am

Hello Stephan3D,
really big dwarf (sorry for the joke of words :P ).
As your first test, really not bad! Compliments. And how perfect texturization :!:
Now you must scans the others six dwarfs :D

Again compliments,
Mattia
PC: DELL M90, Intel T7200, 4 Gb Ram, nVidia Quadro 3500FX.
SO: Win 7 64Bit.
CAMs: USB CCD Color (1024x768, 30 fps) & Canon EOS 1000D.
LENS: 12 mm & VariFocal 3,5-8 mm.
PROJECTOR: ACER K11 & DELL M110.
LASERS: 5mW and 16 mW.
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Hello all

Postby Stephan3D » Sat Feb 07, 2009 9:14 pm

@ MagWeb
Thanks for the info, works perfectly.

@ Hal
.. this is the last one dwarf, the others are gone, with Snow White. :P
Thanks for the compliments.
How you ever say, good, but not perfect. :wink:
With my new set up, I have better scans and better textures.
But I am still a beginner, I am still testing.

here is my second test.

Stephan

Edit: Here you can see that the texture is blurred.
It was on my wishlist:
1600x1200 texture receptive to 800x600 scan

With larger / sharper texture would all still look better
Attachments
Engel.jpg
Original (9 cm)
Engel scan.jpg
My new scan
PC: Intel I7, 3,2GHz, 6GB Ram, Geforce GT550Ti, Win7 64
Cam: Logitech QuickCam Pro 9000
Laser: LC650-5-5-F(14x45)-NT,Wellenlänge: 650nm,Opt Leistung: 5mW
Beamer: Acer C20
Stephan3D
 
Posts: 45
Joined: Sun Jan 18, 2009 11:24 am
Location: Germany

two angels for David

Postby hal » Sun Feb 08, 2009 10:48 am

Hi Stephan3D,
you are an hard-working user of David, and this forum need people like you. Again Compliments for your last angel-scan, probably the real brother of the Sven & Simon's angel-scan :).
I see that your tests are more than good scans: they are great tests! What do you think to open you personal space into the Wiki's Multimedia Gallery? I think that yours are interesting results and you can upload your 3D .pdf files and/or videos in David's Wiki.
And why not a tutorial? Your works show us a clean workflow of scanning + texturing. What do you think to contribute to David's learning uploading a tutorial into Wiki?

I hope to see more beautiful scans of yours, greetings,
Mattia
PC: DELL M90, Intel T7200, 4 Gb Ram, nVidia Quadro 3500FX.
SO: Win 7 64Bit.
CAMs: USB CCD Color (1024x768, 30 fps) & Canon EOS 1000D.
LENS: 12 mm & VariFocal 3,5-8 mm.
PROJECTOR: ACER K11 & DELL M110.
LASERS: 5mW and 16 mW.
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Location: Cavaria con Premezzo (VA), Italy.

David Wiki

Postby Stephan3D » Sun Feb 08, 2009 5:56 pm

Hi hal,
No problem, tell me where, and I invite high.
I'm just on my next project, but had problems (bug) with the textures. :(
Leave just a bug report

stephan
PC: Intel I7, 3,2GHz, 6GB Ram, Geforce GT550Ti, Win7 64
Cam: Logitech QuickCam Pro 9000
Laser: LC650-5-5-F(14x45)-NT,Wellenlänge: 650nm,Opt Leistung: 5mW
Beamer: Acer C20
Stephan3D
 
Posts: 45
Joined: Sun Jan 18, 2009 11:24 am
Location: Germany

Re: Scans not accurate enough

Postby hanif_mahat » Wed Feb 11, 2009 5:24 am

im very envy to all of u guys here :evil: ....Good works :P
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