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Camera for high precision scanns

Problems, solutions and discussion about scanning with a video projector and stripe patterns.

Camera for high precision scanns

Postby mire » Tue Oct 18, 2016 9:15 pm

Hi, i want to make high precision scanne of small objects 15x15x15 cm.
For a higher precision is it better to use a 4K camera?
may be i need to build a exact calibratio corner?
And which projector sould i use?
What else is necessary get the highest precision?

Thanks Michael
mire
 
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Re: Camera for high precision scanns

Postby Curiousjeff » Wed Oct 19, 2016 8:42 am

Hi,

15 x 15 x 15 is not so small.

What precision are you looking for in micron?

The choice of equipment depends on your budget.

I had bad experience with DLP projector that have diamond shaped pixels.

Micr0 has purchased what seems to be the best projector for David (LG PF1500), but the price is higher then the Acer recommended by the David company.

Have a look at Micr0 posts.

Regarding the camera, I believe I am the only one who tested 4k and wrote about it. Obviously a higher resolution camera will increase precision but will have side effects : size of scan, longer time to scan, process and align, etc...

My test was done with a Panasonic GH4 (look at my thread on 4k). The video signal has some jittering that creates surface artifacts. Possibly an industrial bw 4k camera would immuned to these issues.

Calibration: yes, you will maybe need to make your own calibration board.

Since David has a lego philosophy, I would recommend buying the projector and then testing 4k before committing to the purchase.

Personally, I think a fullhd camera is enough. Again, I can only recommend that you search the forum threads (Micr0, Narmella).

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: Camera for high precision scanns

Postby Curiousjeff » Wed Oct 19, 2016 9:08 am

PS My 4k setup does not work under Windows 10. For that purpose, I have double boot.

I have not tested 4K with David 5.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
Curiousjeff
 
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Re: Camera for high precision scanns

Postby mire » Wed Oct 19, 2016 9:01 pm

15 x 15 x 15 cm is the maximum. Most of my objects are smaller (about 25 x 25 x 50 mm) and with many details. You can see some of my obejcts in the picture.

The precision i'm looling for is about 5 micron.
The budget is secondery.
What is the benefit of using stereo camea?
Attachments
image.jpg
mire
 
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Location: Germany

Re: Camera for high precision scanns

Postby Curiousjeff » Wed Oct 19, 2016 9:22 pm

I don't think 5 micron is possible for the moment using David.

On David's web site they says that with the fullhd camera and the Acer projector, you can get around 50 micron.

Maybe with a industrial 4K camera and the LG projector PF1500G (full hd), you could get down to 25 micron (???).

But you must take into consideration that if the items are in metal, you will need to coat them before scanning, and this will remove precision.

For stereo camera benefits, have a look at the messages from Sven in the David 5 thread.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
Curiousjeff
 
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Re: Camera for high precision scanns

Postby mire » Sat Oct 22, 2016 2:44 pm

I want to use david to measure objects like in the picture above for quality check.
There is a company how offers a system that use the same technology like david.
They can measure 5 micron.
With optimal hardware and high precision clibtation it must be possible.
Or am i wrong?

Michael
mire
 
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Joined: Tue Sep 27, 2016 2:16 pm
Location: Germany

Re: Camera for high precision scanns

Postby drndadoo » Tue Oct 25, 2016 10:22 am

Your task is next to impossible. Gom gives you 5 microns, but the price is over 100.000€
So far this is the bes micro scan that I saw here:
viewtopic.php?f=15&t=4491&hilit=micro
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