Camera for high precision scanns

[mire]

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

[Curiousjeff]

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

[Curiousjeff]

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

[mire]

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?

[Curiousjeff]

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

[mire]

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

[drndadoo]

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