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Author Topic: 4D Scanning?  (Read 15115 times)

Mr_Curious

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4D Scanning?
« on: February 13, 2013, 02:22:34 PM »
I'm interested in trying to do 4D scanning with Agisoft.  Can anyone who has done it (or knows how to do it) explain to me what is required and provide me with step-by-step by instructions regarding the procedure?

I really would like to learn more about how to do this and would appreciate any help that the community could provide.

Thanks!

Greetings,

Mr. Curious

Wishgranter

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Re: 4D Scanning?
« Reply #1 on: February 13, 2013, 05:28:15 PM »
4D of peoples heads - faces, full body or just common ?

Pscan can generate very detailed results, better than any other solution on the market, but main problematic is to capture it RELIABLY.

For faces expressions is best ot use DSLRs - if need a LOT of details its a combination of Pscan and few other sw to get NORMAL maps - a key to rich and proper details - See the Lee Blog about it http://www.ir-ltd.net/do-you-wanna-live-for-ever

For body is more problematic, "easiest" is a Stop motion - but there is a lot of problems to solve, with DSLRs can get just to aprox 2-4 FPS fro say 2-4 sec then its ends.


Another is to use FAST videocameras (60 FPS ) best with uncompressed output grabbed to PC with proper cards (BlackMagic). Something like http://www.creativevideo.co.uk/index.php?t=product/jvc_gy-hmq10_4k_camcorder but in real scenario you need solve a lot of things....

Have seen few commercial solutions but they offer not so great results, something in quality of Pscan on LOW-Lovest settings...
consider ammount of data envolved too ( GBs of data per sec) - Uncompressed if possible - or get a lot of artifacts from CODECs

So a for WORKING solution you will need a LOT of money, not to mention solving problematic around it - Lights, synchronisation of cameras and etc.......

here is a interesant Whitepaper about it http://gl.ict.usc.edu/Research/DynamicShape/SIGGRAPHAsia2009_DynamicShape.pdf

« Last Edit: February 13, 2013, 05:57:45 PM by Wishgranter »
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Mr_Curious

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Re: 4D Scanning?
« Reply #2 on: February 13, 2013, 06:52:36 PM »
Thank you Wishgranter so much for the very informative and helpful reply!  Very interesting, I will do further research.

Greetings

Mr. Curious

Infinite

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Re: 4D Scanning?
« Reply #3 on: February 13, 2013, 11:51:58 PM »
So a for WORKING solution you will need a LOT of money

THIS.

Anything is possible, if you have the funding. But we are talking 6 figures.

 4D with consumer DSLR's is not really ideal. Too much bad compression, also lack of 60fps at HD. The bonus is good lenses but this is useless if the output quality is bad.

The other big problem is data management. Uncompressed even at HD, 60fps can be quite hard to manage, let alone at 8MP or 12MPx the number of cameras you want to set up.
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EricM

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Re: 4D Scanning?
« Reply #4 on: February 16, 2013, 12:40:50 AM »
Anyone tried with the new GoPro Hero 3 ?

4K at 15fps might be ok and the price reasonable. You can also sync them with the remote (up to 50).

Wishgranter

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Re: 4D Scanning?
« Reply #5 on: February 16, 2013, 02:21:46 AM »
http://abekislevitz.com/understanding-your-new-gopro/

BUT, try understand problematic around photogrammetry - the BASIC stuff

Syncing of frames - a bigest issue, the rolling shuter, try calculate amount of movement per 1 frame, try think that every cam is out of sync with other ( calculate movement of object  for 60ms ) - try understand the problematic of this very basic stuff......  You need a 60FPS !! not a 15FPS see this video and see on the flip-flap, how sharp is it.....
 
http://dl.dropbox.com/u/7739716/GoPro%20Hero%203%20Black%204K%20Sample%20Video/GOPR0001.MP4


compression ratio - try save in pshop or something, few test files with higher and higher compression ratio - have tested with pshop 0-12 levels, under 9 you get noticeably lower amount of features detected. 4k is commpresed to aprox 45Mbits/s that mean a lot of compression - just from head, aprox. lev 8-6 on JPG sett.   

As have mentioned earlier you need UNCOMPRESSED video, or just very very light compression or you get in problematic about CODEC artifact..... you need a 4:4:2 videosignal and not 4:2:0 or even lower.....


Believe me, if this was a option it was already used and the one who could solve it, not theoreticaly but practicaly, would be working with it in many studios already....

From theoretical point of view is a lot of things possible, but see only Lee has a working "PROTOTYPE" thats reliable, and even on 18Mpix its problematic to get clean results and its MONTHS of testing how to get reliable results............


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scanlab.ca

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Re: 4D Scanning?
« Reply #6 on: February 18, 2013, 10:38:59 PM »
Anyone tried with the new GoPro Hero 3 ?

4K at 15fps might be ok and the price reasonable. You can also sync them with the remote (up to 50).

I've tried the GoPro Hero3 as soon as it came out, but the results were not impressive.
The wide angle lens requires the subject to be way too close to the camera, otherways there's a major los of detail (and 12mp in not much anyway). So there's really no room for action.

The optics are pretty subpar, the claimed 4k resolution is a rescaled 2.7k. Still lots of noise, aberration, autoleveling: the whole package.

Best regards,

Ruslan Vasylev | Scanlab Photogrammetry
S: https://scanlab.ca | E: ruslan@scanlab.ca | T: 1 (778) 991-5157

Wishgranter

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Re: 4D Scanning?
« Reply #7 on: February 20, 2013, 02:46:36 AM »
Hello all, have googled few things, will put it together and present it here in next few days....... Some interesting stuff for learning and eventualy testing....
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Mr_Curious

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Re: 4D Scanning?
« Reply #8 on: February 20, 2013, 01:47:24 PM »
Hello all, have googled few things, will put it together and present it here in next few days....... Some interesting stuff for learning and eventualy testing....

Awesome Wishgranter!

I am always interested in your research.

Greetings,

Mr. Curious


andy_s

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Re: 4D Scanning?
« Reply #9 on: February 20, 2013, 01:55:16 PM »
+1 - looking forward to it Wishgranter  :)

Wishgranter

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Re: 4D Scanning?
« Reply #10 on: March 15, 2013, 03:33:29 AM »
For the ones interested in 4D scanning with structured/white light technology contact me with PM.. its FREE app, implemented best stuff, direct from research.... 
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FoodMan

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Re: 4D Scanning?
« Reply #11 on: March 15, 2013, 10:47:36 AM »
oups... a free structured light app...? Interesting..  8) 8)

Infinite

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Re: 4D Scanning?
« Reply #12 on: March 15, 2013, 02:04:14 PM »
For the ones interested in 4D scanning with structured/white light technology contact me with PM.. its FREE app, implemented best stuff, direct from research....

Why not openly post the link here? if it's free.
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Wishgranter

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Re: 4D Scanning?
« Reply #13 on: March 15, 2013, 02:12:56 PM »
Im want not confuse people when searching for 3D-4D stuff therefore was with PM in mind....

Its based on this research http://public.vrac.iastate.edu/~song/publication.htm

Whitepapers are located here http://public.vrac.iastate.edu/~song/publication.htm#jnls

Software based on this is here:

http://www.real3d.pk/3dracs.html


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Infinite

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Re: 4D Scanning?
« Reply #14 on: March 15, 2013, 02:37:04 PM »
Interesting thanks Wishgranter.
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