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Author Topic: Turntable Requirements  (Read 28994 times)

BizzleZ

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Turntable Requirements
« on: November 21, 2013, 09:29:51 PM »
Hello Agisoft Community!

I'm new to this, but I have been following Agisoft for quitet a while, and am now starting to learn the process of photogrammetry.  When I began, I was under the assumption that you could not use a turntable because the software has to register the image with the movement of the background.  However, as I have looked around the forum, I see that others are creating turntable rigs.

If turntables are valid for APS, what are the requirements/best practices for setting up a turntable?  Do you need registration markers on the table?  Anything particular in the background? 

Exciting stuff, and APS is an absolutely amazing tool!  Thanks for the input :)


chadfx

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Re: Turntable Requirements
« Reply #1 on: November 21, 2013, 10:38:56 PM »
Turntables definitely work. Soft/diffused lighting to minimize shadow/highlight changes helps. Most likely you will need to use some sort of masking to isolate your object from the static environment. So if you can use a solid color background that is different from your subject, that can help automate the process.

Good luck! -C

admir

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Re: Turntable Requirements
« Reply #2 on: November 22, 2013, 12:18:38 AM »
We have white sheet in background and it works very well. Another thing we did is to place white sheet over turntable as well. With white sheet you get nice light bounce as well, and our subjects wear darker color clothing so constrast is there . When you finish shooting your subject, remove it from turntable, shoot one photo (for each camera) with just background. You can use that image as automatic mask in PS.

There is no need for markers of any kind.

Hope it helps,
Admir

Hayato

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Re: Turntable Requirements
« Reply #3 on: November 22, 2013, 01:32:43 PM »
Hello Everyone! :)
Nice to meet you!
I want to make a full body scan system at a low cost as possible.

If you use a turntable,
Do I need a how many number of the camera for full body scan?

Hayato Nishimura
from JAPAN

meshmixup

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Re: Turntable Requirements
« Reply #4 on: November 22, 2013, 01:49:19 PM »
Hi Hayato,

The purpose of turntable is to change the angle of photo taking. So provided that the model can keep the position, you can use three camera (head, body trunk, foot) to take 360 body scan. The model should be in relax position, breath slowly ....... it is fun;D

Cheers,
Jim

admir

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Re: Turntable Requirements
« Reply #5 on: November 22, 2013, 02:00:18 PM »
Our turntable system used 4 Canons. It rotated 38 second, each second 1 image was taken so we ended with 4x38 = 152 images + 1 empty background.

For full body scan, it is low number of cameras plus there is optic distortion and resolution issues added on top of subject slightly moving (tips of hands, head....). To compensate for that we shot fullbody (used as reference), top, legs, head, boots and arms separately and merged them together using fullbody scan as reference. As our field is real time games, results were very very good. For head, boots and immovable objects we used simple white chair with subject sitting on it or item placed on chair.

Hope it helps,

Admir

Hayato

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Re: Turntable Requirements
« Reply #6 on: November 22, 2013, 02:47:27 PM »
Hi Jim & Admir,

Thank you for a great answers. ;D
I will try it.
And I will report the results.

Since I have the Nikon D5200 possession of one already,
It is planning to buy 600D other three.

I would like to see the 3D model of the result of using a turntable and four cameras.
It's possible?

Best regards
Hayato Nishimura

admir

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Re: Turntable Requirements
« Reply #7 on: November 23, 2013, 11:25:17 AM »
4 cameras are possible. You need to sync external flashes to cameras and adjust shooting options on cameras. This is trickiest part as getting sharp, well lit images is key to good solution.

 I have attached 2 images examples of 4 Canon rig and turntable. Those are raw scans from PS without editing.

Hayato

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Re: Turntable Requirements
« Reply #8 on: November 23, 2013, 12:24:14 PM »
Hi Admir,

Thank you for your kindness.
It's a fantastic!
I believe this is a sufficient quality for 3D printing.
I'll try it!

 ;D

Best regards
Hayato Nishimura

Exhale

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Re: Turntable Requirements
« Reply #9 on: November 23, 2013, 01:27:18 PM »
Hi Admir,

That looks cool dude... If the person had kept arms closer to body, it would be better, wouldn't it? :)
But anyways , that is remarkable job... well done.

admir

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Re: Turntable Requirements
« Reply #10 on: November 23, 2013, 01:46:57 PM »
Thnx!

Yes, with arms closer it would be less character movement, however some parts could be occluded and not scanned.

Attached are couple more examples...

Admir

Hayato

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Re: Turntable Requirements
« Reply #11 on: November 25, 2013, 02:47:30 AM »
Hi Admir

Thank you for additional information.
It's a wonderful.

Where can I purchase a your recommend turntable?
« Last Edit: November 25, 2013, 03:38:27 AM by Hayato »

Exhale

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Re: Turntable Requirements
« Reply #12 on: November 25, 2013, 01:05:47 PM »
Hi Hayato,

There isn't any turntable ready for sale I believe. So you should make your own custom build turn table.
You need electric motor something like this: http://puchberger.nl/Draaiplateaus.htm
I believe you can find something like this in your country..
Good luck,  keep us updated  ;)

admir

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Re: Turntable Requirements
« Reply #13 on: November 25, 2013, 01:37:48 PM »
Hi,
good inspiration on building your own rig is Mark Florquin's blog:http://www.markflorquin.be/blog/2013/01/full-body-scan-3d-photogrammetry-photoscan-nikon-rig-d80-d7000-d700/.

We built our own using engine from electric owen http://www.mada.cn/productsshow_en.asp?id=10 .
It is connected to turntable using bicycle inner tire to provide constant rotation without jumps.

Admir

Hayato

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Re: Turntable Requirements
« Reply #14 on: November 25, 2013, 03:08:52 PM »
Hi

Thank you for your kindness.
It's a fantastic!
I'll try & learn it.

Best regards