Crown of Thorns

[Simon]

I'm currently working on an improvement of Poisson fusion. The goal is to get sharper results (like in simple fusion). During testing different methods, sometimes really strange things happen... . So I don't want to withhold this mysterious image:

[Khalid Khattak]

Simon, You accidently created a master piece:)... I really liked it.. Did you scan with SL functionality(eyes opened)..seems you are working hard to improve the already improved David:)
thanks

[Simon]

Did you scan with SL functionality(eyes opened)

Hi,
no SL, we scanned the head with our focusable laser. The LE650-5-3-F-S (which is also included in the starter-kit) is classified as "eye save"...
BTW: The scanned person was a well known German television presenter Dennis Wilms (compare mesh2flash). We made a full body scan of him for his TV show. The head was scanned seperately and fused with the rest of the body using Poisson fusion to get more details in the face.

[Ben4096]

Hi,

Very interessting, I'm working on a rig to scan full bodies and maybe soon we could compare our results
I'm impressed by the fact you've scanned him with open eyes. There're so much warning on this forum against that and even on the wiki "Never look into laser beam".
I don't think I will try, but I'm just curious. Since all the laser from the shop are "Class 1" would say there are all ok for opened eyes scanning ?
And what about my LE532-5-3-F-S ?

ben

[WalterMo]

Hi Ben,
The danger of the laser light for humans is a hot potato. We can read laser 'Class 1' for most of the picotronic 5mW line lasers. And we can find according to regulation for Class 1 a power of < 25µW, but we have 5mW. This would be Class 3R. That means dangerous for the eyes!

And now comes the opening angle:
In contrast to point lasers which don't open the beam, line lasers mainly have an opening angle of 60° or 90° and distribute their energy over the line. So it is difficult to specify which power at which distance.
For your (face) scans you are using a relative high scan speed. Therefore it might be not so dangerous for the eye because also the exposure time is playing a major role.
For example: Laser Class 2 is specified for lasers up to 1mW and not dangerous if the exposure time is not longer than 0.25 sec.
And what about the reflex of the eyes to close its lids automatically when suddenly a high brightness appears? Was the eye scanned opened or closed? With your method I think opened.
And we are scanning nearly in darkness. That means the pupil of the iris is widely opened.

My résumé: Be very careful!

Walter

[Ben4096]

Thanks for clarifying that Walter.

If I have the opportunity I'll try on a German tv presenter, but definitly not on myself or a friend.

ben

[WalterMo]

Let's have a look onto this calculation:

At a distance of 1m the line length is 2m of a laser with an opening angle of 90°. And let us assume that the intensity over the line length is everywhere the same and that the power is 5mW. The max. diameter of the pupil is specified to 8mm. Then the 5 mW power, distributed over the 2000 mm long line, will hit the 8mm opened eye with a power of 20µW. Under these conditions we will have laser Class 1 for the 5 mW line laser and are allowed to scan eyes.

Walter

P.S.: Ben, now you can also scan French tv presenters.

[hal]

Hello Walter,

Thanks for your infos: they are important concepts and not already in mind of all Davidians, old and new (me, too).
So, I ask to you: what do you think to write a quick paper for the Wiki pages? Already exist this page, but maybe a more exaustive text is needed. If you can (and want) you can add more infos and examples (maybe referred to the David Shop lasers), like you had already done in your previous messages.

Hope that you can help us to clarify the REAL laser risks and help us to avoid false worry or dangerous irresponsibility.

Thanks in advance
Mattia

[WalterMo]

OK Mattia,
But before I write something on the WIKI, I must clarify how the guys from the DAVID shop specify their lasers, e.g. this one with 16mW to Class 1M:
https://ssl.david-vision-systems.de/sho ... 7fab98f48c

Walter

[Ben4096]

Hey Walter,
I've tried... I'm weak and curious... my bad...
Good news is I still can see !
Let's be clear, and speak serious. I'm using a LE532-5-3-F-S, not focussed on my eyes, at 2,5m, for less than 0,25sec, not in a dark room. I don't recommand to do it and I won't do it again.
So scans are usable, but poor. And reconstruct from closed eyes using Zbrush or Mudbox is I think a better way to go. At least it's the best advice to give to anyone.

P.S : I know some french tv presenters who deserve Class 4..

ben

[MagWeb]

Hi,

think the safest way to scan open eyes is to use a video projector instead of a laser ( either using a moving line or SL). Here you can dim down the beam or the projected patterns using not Black-White but a Grey-Black contrast.

BTW: TV moderators are trained to look right into some bright lights by their daily job - doesn´t mean that their eye can stand more light, but they have technics to control their lids