David / HP 3D glass calibration panel vs DIY

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Curiousjeff
Posts: 121
Joined: 16 Nov 2016, 22:31

David / HP 3D glass calibration panel vs DIY

Post by Curiousjeff »

Is there any reason to prefer a DIY solution for building a precise calibration panel vs purchasing the glass calibration panels form HP ?

The price is reasonable (around $ 250.-)

I just want to make sure the precision is high.

Jeff
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VDX
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Joined: 05 Feb 2017, 10:43

Re: David / HP 3D glass calibration panel vs DIY

Post by VDX »

... for me the price for a DIY panel is negligible - maybe 5€ for the panels and 1€ more for the adhesive (or nothing for smaller than 200x200mm) ... but only, because of my tools and resources.

Could be a totally different equation for others ...

Viktor
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Curiousjeff
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Joined: 16 Nov 2016, 22:31

Re: David / HP 3D glass calibration panel vs DIY

Post by Curiousjeff »

In this case, I am not concerned with the price, but I would like to make sure that the HP panel it is of the highest quality /precision.

Does any one on the forum use it?
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VDX
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Joined: 05 Feb 2017, 10:43

Re: David / HP 3D glass calibration panel vs DIY

Post by VDX »

... the quality/accuracy depends on the printing methode and/or service provider, they use to make the panels -- and, of course, on the fabbing (injection-moulding, milling, ...) quality of the brackets.

Could be, my "DIY" is one order of magnitude better than HP's ;)

Viktor
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spark
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Joined: 06 Mar 2017, 20:44

Re: David / HP 3D glass calibration panel vs DIY

Post by spark »

Hi, i am using the orig. david panel, but i am still tuning my scanner setup for best results.
So far i have no idea how good the glass panel is. i bought some original equippment parts to start with less contributors to quality issues as possible.
Do you have an idea how to check the fabrication quality? Mybe all my problems results from a low quality batch of this panels :-P /dont think so.
i also read between the lines in several threads, that david corrects some imperfections in their software?
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VDX
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Re: David / HP 3D glass calibration panel vs DIY

Post by VDX »

... you get some errors by position displacement of the marks and some more on not correct set 90deg between the panels.

But most errors will accumulate by the optical equipment - optics and objectives of the cam and beamer.

David software has some error correction, but this will reduce only some percents of error, while can generate some new.

You can see the wrong calculations when overlaping (mostly on the borders of the scans) - best strategy to avoid or reduce this errors is to reduce/cut the borders by some 10 percents ... so make much more scans with big overlapping areas, so you can remove the "questionable" parts ...

Viktor
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spark
Posts: 43
Joined: 06 Mar 2017, 20:44

Re: David / HP 3D glass calibration panel vs DIY

Post by spark »

is it possible to automatically avoid the critical areas of the scan field?
project larger pattern than camera field of view to avoid borders of the projectors lens
use the crop factor of lens/sensor size combination to avoid distorted areas of the optics
limit the depth of a scan-data automatically?
//but all this is next to your initially question of the calibration panels
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