Agisoft Metashape

Agisoft Metashape => General => Topic started by: BizzleZ on November 21, 2013, 09:29:51 PM

Title: Turntable Requirements
Post by: BizzleZ 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 :)

Title: Re: Turntable Requirements
Post by: chadfx 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
Title: Re: Turntable Requirements
Post by: admir 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
Title: Re: Turntable Requirements
Post by: Hayato 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
Title: Re: Turntable Requirements
Post by: meshmixup 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
Title: Re: Turntable Requirements
Post by: admir 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
Title: Re: Turntable Requirements
Post by: Hayato 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
Title: Re: Turntable Requirements
Post by: admir 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.
Title: Re: Turntable Requirements
Post by: Hayato 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
Title: Re: Turntable Requirements
Post by: Exhale 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.
Title: Re: Turntable Requirements
Post by: admir 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
Title: Re: Turntable Requirements
Post by: Hayato 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?
Title: Re: Turntable Requirements
Post by: Exhale 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  ;)
Title: Re: Turntable Requirements
Post by: admir 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
Title: Re: Turntable Requirements
Post by: Hayato 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
Title: Re: Turntable Requirements
Post by: meshmixup on November 26, 2013, 04:41:31 AM
Hi there,

And how about this?  8) http://www.amazon.com/Arqspin-ARQ-110-10i-s-12-Photography-Turntable/dp/B00CA7SVK2
I used a turntable with ~0.6 rev/min. It is too hard to keep the pose if it turn too fast. You may consider to add arm rest to make your pose even more stable. ;D
Title: Re: Turntable Requirements
Post by: Hayato on November 26, 2013, 08:46:46 AM
Hi meshmixup,

Thank you for your additional info.

Good machine!
User review, but worrisome,
It's so low price!

Best regards
Title: Re: Turntable Requirements
Post by: Magnus on November 26, 2013, 09:33:43 AM
Hello!

This topic brought to mind what I had found when I searched for similar things before so I thought I'd share.

Here is a turntable built with a wheel hub from a car http://cheesycam.com/motorized-lazy-susan-heavy-duty/ (http://cheesycam.com/motorized-lazy-susan-heavy-duty/) and funnily enough in the comments on that post there is this http://www.thingiverse.com/thing:28454 (http://www.thingiverse.com/thing:28454)

Might help.

Best, Magnus.
Title: Re: Turntable Requirements
Post by: admir on November 26, 2013, 11:02:35 AM
Hi Magnus,
Our turntable is based/similar on Lazy Susan design.
Just note to Hayato, you would need the way to sync flashes and cameras so delay in shooting is minimal.

There are various solutions explained in forums.

Admir
Title: Re: Turntable Requirements
Post by: Hayato on November 27, 2013, 03:39:25 AM
Hi,

I am thinking of buying this.
https://arqspin.com/360-spin-hardware/arqspin-24-large-motorized-turntable/

It can not seem to adjust the speed.

What do you think about this?
Is there a problem?


Best regards
Hayato Nishimura
Title: Re: Turntable Requirements
Post by: Hayato on November 27, 2013, 07:50:50 AM
Hi,

Turntable I'm considering buying is 30 seconds per rotation.
Is this too fast?

Best regards
Hayato Nishimura
Title: Re: Turntable Requirements
Post by: admir on November 27, 2013, 12:06:42 PM
Our 1st turntable had 26sec per rotation so it shouldnt be problem if you can shoot cameras and flashes that fast.

A
Title: Re: Turntable Requirements
Post by: Exhale on November 27, 2013, 12:28:09 PM
Yes, I totally agree with admir.
I have custom build turntable . It looks the same with what Hayato is going to buy.. Just there is extra custom programmed micro chip.  I can decrease or increase the speed. It makes the things esier.. My turntable makes 1 revolution per minute.  Even I can adjust it for 1 revolution in 70 or 80 seconds... Very useful for me :)
Title: Re: Turntable Requirements
Post by: BizzleZ on November 28, 2013, 03:03:32 AM
Awesome information, everyone!  You guys are a great resource.  So I'm understanding that a turntable is completely fine as long as you mask the background out, correct?

Thanks!
Title: Re: Turntable Requirements
Post by: Hayato on November 28, 2013, 04:42:51 AM
Hi everyone,

Thank you for your reply.
I decided to buy it.
I will report here the results.

 ;D

Best regards
Hayato Nishimura
Title: Re: Turntable Requirements
Post by: admir on November 28, 2013, 10:05:51 AM
Awesome information, everyone!  You guys are a great resource.  So I'm understanding that a turntable is completely fine as long as you mask the background out, correct?

Thanks!

Turntable is great for standing still objects and similar, very good for characters (as it depends on person being able to stand/sit still for a fairly long period of time). Yes, masking background does the magic and reduce calculation times. Good light and shooting params (Iso, f-stops...) are the most important to get sharp,well lit photos.

Admir
Title: Re: Turntable Requirements
Post by: MiloMilo on November 28, 2013, 11:34:45 AM
I'm a little unclear on the workflow for capturing an object shot on a turntable. I have 36 shots of the object as it was rotated, then one shot of the turntable and background without the object for use as a mask. What are the actual steps for using that background shot to mask the images so the object can be recreated?
Title: Re: Turntable Requirements
Post by: admir on November 28, 2013, 12:41:02 PM
I'm a little unclear on the workflow for capturing an object shot on a turntable. I have 36 shots of the object as it was rotated, then one shot of the turntable and background without the object for use as a mask. What are the actual steps for using that background shot to mask the images so the object can be recreated?

From Tools menu, select Import->Import masks. In first pulldown choose chunk (usually you have one, so select Active). For Method choose Background. Navigate to folder with background in .png.

For more about Masks, check manual in "Using masks" part.

Admir

Title: Re: Turntable Requirements
Post by: MiloMilo on November 28, 2013, 01:17:25 PM
Great thanks- checked the manual but could not figure it out. Much appreciated.
Title: Re: Turntable Requirements
Post by: EMULAT3D on December 02, 2013, 06:16:49 AM
I have yet to try using the mask from background feature in Agisoft as I've been creating key's from a green screen background. How are you ensuring that the background exposure is the exact same with and without the subject? Exposure locking? Or does Agisoft have some tolerance when it comes to this?
Title: Re: Turntable Requirements
Post by: Hayato on December 02, 2013, 08:41:28 AM
Hi everyone,

I will use standard 18-55mm lens and Nikon D5200, and i will try this turntable system.
Please tell me about the optimal distance between the camera and the subject?

Best regards
Title: Re: Turntable Requirements
Post by: Hayato on December 02, 2013, 09:53:54 AM
Taking 30 sheets can be difficult to continuous shooting of RAW.
Is it okay to to JPEG?
Title: Re: Turntable Requirements
Post by: Exhale on December 02, 2013, 10:31:55 AM
Hi,
Yes, you are having problem because as admir said "you need to sync flashes and cameras" this is must.
Adjust the flashes position and make sure there is no shadow or anyother differance on the background.  RAW or JPEG doesn't make huge differance.

by the way, upload some photos and ps data if it is possible..
Title: Re: Turntable Requirements
Post by: admir on December 02, 2013, 12:51:26 PM
I have yet to try using the mask from background feature in Agisoft as I've been creating key's from a green screen background. How are you ensuring that the background exposure is the exact same with and without the subject? Exposure locking? Or does Agisoft have some tolerance when it comes to this?

Shoot with manual focus and white balance. That ensures same focus, same exposure.
Title: Re: Turntable Requirements
Post by: Hayato on December 03, 2013, 08:58:30 AM
Hi,

Thank you for your reply.

I am a stage considering what to do.
After purchasing them, I will do the test.
At that time, I will post the image.

Best regards.
Title: Re: Turntable Requirements
Post by: admir on December 03, 2013, 11:02:00 AM
Hi,

Thank you for your reply.

I am a stage considering what to do.
After purchasing them, I will do the test.
At that time, I will post the image.

Best regards.

Good luck!

Admir
Title: Re: Turntable Requirements
Post by: EMULAT3D on December 05, 2013, 05:47:17 AM
I have yet to try using the mask from background feature in Agisoft as I've been creating key's from a green screen background. How are you ensuring that the background exposure is the exact same with and without the subject? Exposure locking? Or does Agisoft have some tolerance when it comes to this?

Shoot with manual focus and white balance. That ensures same focus, same exposure.

Hey Admir!

Thanks for the tip, I will be giving the manual white balance a go during my next round of tests.  ;D
Title: Re: Turntable Requirements
Post by: thesystemera on June 27, 2014, 01:09:35 PM
Hi Exhale. Names Simon, from New Zealand.

I'm building a photogrammetry studio (really just starting). A simple camera rig of four Canon EOS 600D's rigged on varying angles in accordance with a rotating Lazy Susan. Well that's the idea.

Would love to know how you build your custom Lazy Susan with micro-controller. It would be awesome if one could alter speeds or even have intervals of on-off timed with triggered capture as to eliminate an motion blur (no matter how mild).

Did you buy a pre-packaged solution, was it a DIY guide. Very interested to know. Only got a very small business grant to try and pull this off and don't want to spend unnecessary cash on mistakes. If you think I'm taking the wrong route and have any suggestions regarding cheap alternatives, I am all ears.
Title: Re: Turntable Requirements
Post by: elisa.laviolette on October 11, 2014, 11:25:38 AM
Hi everyone,
I was thinking of buying this 12" turntable from Arqspin too, in order to make capturing faster (I am currently testing 3D modeling of archeological stone tools, and I have a lot of them to capture...).
Hayato, can you tell us how this setup works for you ?

Thx,
Title: Re: Turntable Requirements
Post by: dariusp on October 13, 2014, 06:36:19 PM

Hi everyone,
I was thinking of buying this 12" turntable from Arqspin too, in order to make capturing faster (I am currently testing 3D modeling of archeological stone tools, and I have a lot of them to capture...).
Hayato, can you tell us how this setup works for you ?

Thx,

I've recently purchased a turntable and "ELECTRONIC DEGREE TIMER STOPPER" from http://www.studiotent.com/. I'm currently working with a museum to scan various items and this setup will help greatly. You use the timer to control the turntable rotations, "turn for 3 secs then pause for 5 secs." etc. Combined this with a timer on the DSLR and can photograph an object in under 4 minutes, will speed up process and provides more accurate overlap.

Not sure if works out cheaper than Arqspin, my setup was about £150.

Done a quick test and is very simple, just a bit of maths. Testing it fully tomorrow.