Forum

Author Topic: Turntable or walk around?  (Read 4009 times)

LoL-Fighter

  • Newbie
  • *
  • Posts: 5
    • View Profile
Turntable or walk around?
« on: May 18, 2016, 01:00:09 PM »
Hey everyone!
First of please excuse my bad english-skills  ;D

A while ago i came across the idea of 3d scanning. First i was looking for a good 3d handscanner but they are way to expensive!

So after some searching i found the soluton of agisoft photoscan.

I have some questions about how to take the picture.

Do i have to walk around the object or is it possible to use a turntable?
My plan is to set up a litte white box, fix light setting, fixed camera and a turnable table with some marks on it.. oh yeah and of course some sort of object :)

Is the software able to tell the roation of the object with the help of the marks on the table?
Is fixed light a problem? Because every turn the object casts a slitly different shadow!?
If all is possible.. does the object have to be perfectly centered?

I read the documentation but ther is only the case explained when you walk around the object.

Would be realy cool if you can give me some informations!

Kiesel

  • Sr. Member
  • ****
  • Posts: 332
    • View Profile
Re: Turntable or walk around?
« Reply #1 on: May 18, 2016, 11:23:14 PM »
All possible!
This forum and the web is full of turntable solutions! For a video tutorial see for example:
https://www.youtube.com/watch?v=9_F-b2hxP_o

LoL-Fighter

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: Turntable or walk around?
« Reply #2 on: May 20, 2016, 07:21:13 PM »
Thank you for this video, it answered a lot of questions.

Anyway im having a bad time with the turntable method.

If i take the camera in my hands and take pictures of every angle it works more or less good but i get some result.
But if i set up a fixed camera with a object on a turntable camera align is absolutly a mess.

Here is a screenshot of the camera align:
http://bananapi.noip.me/tmp/agisoft/screen1.PNG

And here a sample of one of my pictures:
http://bananapi.noip.me/tmp/agisoft/IMG_3118.JPG

Can someone please tell me what im doing wrong?

Alexey Pasumansky

  • Agisoft Technical Support
  • Hero Member
  • *****
  • Posts: 14890
    • View Profile
Re: Turntable or walk around?
« Reply #3 on: May 20, 2016, 07:27:32 PM »
Hello LoL-Fighter,

I think that the problem is related mostly to the lack of the features on the object's surface. Also the object itself occupies only a small part (less than 1/10th) of the image frame space. Also it's still not clear, whether you are using the masks, as I see quite a lot of white points in the cloud that are surely related to the background.

So my suggestion is to perform the tests on a more textured object and use the image frame space more effectively (and, of course, apply masks to cover the static background and use "constrain features by mask" option in the Align Photos dialog).

Quite a time ago already, we made a successful model of a similar object, also using a turntable to capture the cube from top and bottom:
https://sketchfab.com/models/a7b2a74d67784f3f8707d4d674455131
« Last Edit: May 20, 2016, 07:29:13 PM by Alexey Pasumansky »
Best regards,
Alexey Pasumansky,
Agisoft LLC

LoL-Fighter

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: Turntable or walk around?
« Reply #4 on: May 20, 2016, 07:47:03 PM »
wow this cube looks amazing  :o

Thank you for this fast reply!

I hop eits okay to ask some beginner-questions but im pretty new to photography :)

1. First closer to the obect => okay, but is this turntable to big for this or is it not important if 80% of the image a black because of the turntable.

2.how do you mask your images? i used this tutorial (beginning on page 14):
file:///G:/Downloads/Chrome/Supplemental_Instructions_1_Background_Masking.pdf

Is this a good way? Or do you mask your pictures one by one by hand?

3. What do you mean by "constrain features by mask" where do i find this option?


Alexey Pasumansky

  • Agisoft Technical Support
  • Hero Member
  • *****
  • Posts: 14890
    • View Profile
Re: Turntable or walk around?
« Reply #5 on: May 20, 2016, 08:44:14 PM »
Hello LoL-Fighter,

It's better, if the object of interest occupies most of the area on every image. Since background would be masked, such area will not be used at all. As for the turntable plate itself, that depends on the purposes: if you are going to make several shooting sessions placing the object differently on the plate each time, you will likely need to mask the plate as well. Otherwise you can leave it unmasked.

Usually the fastest way is automatic masking from the background (unfortunately can't see the file you are referring to, as it has some local path), but you can always adjust the masks manually, if required.

"Constrain features by mask" is a checkbox in the Advanced section of Align Photos dialog.
Best regards,
Alexey Pasumansky,
Agisoft LLC