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Author Topic: Building a 39 camera full body rig  (Read 19577 times)

ttoke

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Building a 39 camera full body rig
« on: July 24, 2014, 09:04:35 AM »
Hello guys,

We are currently building a 39 camera full body scanner. Setup:
15x  Canon 1100D + random 18-55 lens
24x Canon 1200D + random 18-55 lens
8x 110W softbox lightning
39x triggers (connected)

The cameras are on 10 different stands, 2 of them (front and back) are holding five, most of them four and three are holding only 3. The distance between cameras is 1m. 

We are having difficulties in getting a good scan. The program usually tries to make a model of walls, floor etc. When it does a model of a person, it is usually only half of the body or two separate halfs. We had pretty good scans in the beginning when we had only 24 cameras (of half of the person), but after buying more cameras and lightning, we haven't got any satisfying results.

Some questions:
1) Is there a "perfect" focal lenght? Should we take pictures as big as possible or rather zoom the cameras in and try to make 3 pictures (every angle) of different parts + one big "general" picture?
2) Can the light be in different colour? Should we close the window, shut down the room lightning etc? (room lightning is kind of yellow, softboxes are white).
3) Should we keep the cameras seperated evenly or rather create "clusters" of them?

Any tips are welcome, thanks!
« Last Edit: July 24, 2014, 09:14:51 AM by ttoke »

ruffy

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Re: Building a 39 camera full body rig
« Reply #1 on: July 24, 2014, 12:42:46 PM »
Most people are pretty secretive of their I.P.
You may not find much help here.
Like you, I am having to experiment.
This is going we'll, but takes time.
I think I am close to great results in a few days time.
I have 60 old cameras.
If it works then I will invest in 80 new ones.
Good Luck:)
Ruffy

James

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Re: Building a 39 camera full body rig
« Reply #2 on: July 24, 2014, 01:49:08 PM »
My area is architectural and structural so don't mind sharing some IP :)

With cylindrical concrete columns I found 10 cameras in a ring around the cylinder to be the absolute minimum to get it all to link together, and found 16 to be the practical minimum most of the time.

Humans being a funny shape probably require a few more setups.

You could try more stands with fewer cameras per stand, maybe 3 per stand on 13 stands, to see if it helps you register all the way around, then add more cameras when you can afford to in the areas you need more detail.

Another idea could be to use the 10 stands you have with 3 or 4 cameras each, and slant your stands at an angle so you effectively have 39 cameras evenly distributed all the way round horizontally, albeit at different heights vertically.

You can try moving the cameras further from the subject, up to a point, to increase their view around the subject and therefore increase overlap.

I have had success with focal lengths all the way from 10mm to 55mm on my crop sensor cameras, albeit only ever static objects with a single camera. I would say if you are struggling then go wider to increase overlap, but not to the point where your subject is no longer filling the frame, then zoom in until it stops working.

Back when Infinite started posting on this forum I saw he was getting results with 40 cameras, so it can be done (http://www.agisoft.ru/forum/index.php?topic=385.msg1604#msg1604) but like ruffy says you have to experiment and it doesnt come for free!

CreativeCharacter

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Re: Building a 39 camera full body rig
« Reply #3 on: July 25, 2014, 04:45:33 AM »
I don't think you can look at this site and say people are secretive about their "I.P."s. there is a wealth of information on every possible topic if you hunt around a bit.

ttoke

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Re: Building a 39 camera full body rig
« Reply #4 on: July 25, 2014, 08:41:22 AM »
Thanks guys! I'll keep You updated!

Wishgranter

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Re: Building a 39 camera full body rig
« Reply #5 on: July 25, 2014, 01:40:53 PM »
Hi ttoke.
Good that you want go for FBody scannign but still im highly recomend to ask Lee for consultancy. He knw a lof of things from real use  with all the "secret" stuff. and in   end, you can save 1.000 of EUR when  go afther his  recommendation + you are sooner market ready....
----------------
www.mhb.sk

ruffy

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Re: Building a 39 camera full body rig
« Reply #6 on: July 27, 2014, 10:51:30 AM »
Happy to admit that I may be wrong with people being protective:)
How should I contact Lee for consultancy?

meshmixup

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Re: Building a 39 camera full body rig
« Reply #7 on: July 27, 2014, 03:37:28 PM »
Happy to admit that I may be wrong with people being protective:)
How should I contact Lee for consultancy?

Yes, I want to know too. :)

meshmixup

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Re: Building a 39 camera full body rig
« Reply #8 on: July 27, 2014, 03:42:37 PM »
3 cam per column in portrait mode 35mm and total 12 column can make reasonable results for stand still pose. 3 extra can put at higher position for head close up

ttoke

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Re: Building a 39 camera full body rig
« Reply #9 on: August 08, 2014, 05:53:46 PM »
Thanks! We got some decent results already, a little bit tweaking and it should be OK for us at the moment.

ttoke

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Re: Building a 39 camera full body rig
« Reply #10 on: August 13, 2014, 08:44:43 AM »
Ok, the results weren't good enough. We bought 10 more cameras.

Is there a "perfect" distance from cameras to the centre of the scanner? At the moment I think it's about 1.5-2m but I think we should make it smaller..?

meshmixup

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Re: Building a 39 camera full body rig
« Reply #11 on: August 13, 2014, 10:26:48 AM »
Considering different model poses and DOF, 2.5m radius is more flexible ;D

ttoke

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Re: Building a 39 camera full body rig
« Reply #12 on: August 14, 2014, 09:14:53 AM »
Considering different model poses and DOF, 2.5m radius is more flexible ;D
Thanks!

Should we use same focal lengths on all the cameras? Right now it's a mess - every camera has its own focal length. We use Canon 1200D/1100D "stock" lenses.

meshmixup

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Re: Building a 39 camera full body rig
« Reply #13 on: August 14, 2014, 11:58:27 AM »
I do not have any issue on using different focal length in one shot, PS will do all magics  ;D

Agisoft has the following recommendations on lens settings
Lens:
Fixed lens are preferred. If zoom lens are used – focal length should be set either on
maximal or minimal value, if this condition is not provided each zoom-lens camera should
be calibrated separately;
Try to use minimal possible camera/lens models and different focal length

ttoke

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Re: Building a 39 camera full body rig
« Reply #14 on: August 14, 2014, 12:07:51 PM »
I do not have any issue on using different focal length in one shot, PS will do all magics  ;D

Agisoft has the following recommendations on lens settings
Lens:
Fixed lens are preferred. If zoom lens are used – focal length should be set either on
maximal or minimal value, if this condition is not provided each zoom-lens camera should
be calibrated separately;
Try to use minimal possible camera/lens models and different focal length


Thank You for the help! :)