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Author Topic: Lightfield picture file to .obj or .stl format


Godehardt
newbie
Posts: 6
Lightfield picture file to .obj or .stl format
on: 2012/09/03 15:27

Hello,
I am a newcomer in this forum. One of mey interests is in three-dimensional reconstructions. I am working, e.g., with the DAVID-Laserscanner program for this purpose. Since a lightfield camera stores not only two-dimensional informations but also the depth, then it should be possible to extract not only .jpg files from such a file but also (maybe) enough information for the depth to generate .obj or .stl files (perhaps the .obj files with texture information). Has someone done this already? As far as I know, the Raytrix cameras have between 30 and 100 "layers" of depth; how many of such layers are generated by the Lytro camera? Are there enough to generate 3d files or not?
Best regards,
Erhard Godehardt



markus
Administrator
Posts: 68
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/03 16:26

Hello Erhard!
I'm not familiar with .obj or .stl files, but I think I can answer some of your other questions:
In a processed -stk.lfp file, you'll find up to 12 stack images (or image layers). Processing the raw lfp-file yourself should give you all the depth resolution you want.
Generally, 3D reconstruction is possible with the stack files and depth information contained in an lfp-file, but it depends on your desired depth resolution. For example, here's a 3D render from a web-optimized -stk.lfp file that I found on youtube:



Godehardt
newbie
Posts: 6
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/05 13:18

Hello Markus,
Many thanks for your quick reply. Meanwhile I found that the Lytro file format is open. So it should be possible to convert it to obj or stl or other 3D formats. The problem may be that the depth information is not so "good" as, e.g., in the Kinect or Xtion motion sensor. The video for which you gave the link seems to indicate less than 30 depth "layers". On the other hand, it might be very interesting to se whether photographs from different directions and angles can be registered and stitched together to a complete 3D object, similar to what hes been done by the creators of the ReconstructMe software for the Kinect and Xtion. For the Raytrix cameras, the situation seems to be better (they are a little bit more expensive, too). They have up to 100 depth layers. And maybe that they can be programmed to have even more and thus coming close enough to the Kinect and Xtion motion sensors or to the very new leap motion product. So I try to get also some information about the file structure of the Raytrix cameras. Do you know whether this format is known or not?



markus
Administrator
Posts: 68
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/13 00:39

Erhard, the video was created from the web-optimized (i.e. heavily compressed and simplified) version of a LightField picture. These web versions contain 12 layers at the most, while the raw file contains all information for continuous refocus.
I'm afraid I don't have any info regarding Raytrix' own file format. Yet. ;)
They do have some samples (probably also compressed) online here, and you may be able to search the source code for the data file behind the applet.



Godehardt
newbie
Posts: 6
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/18 08:34

Markus, you are right. Also the pictures from Raytrix seem to be compressed. This can be assumed if you consider the pictures of faces, which are usually very good in their depth information and the pictures containing scenes like those with people in landscape settings which look rather bad when you turn them. I spoke with Dr. Wietzke from Raytrix and he promised to include an export filter to their software so that the information can be exported as obj files and (or) stl files. He said that this would be very simple to be done by them. Perhaps this would be also an option for the people from Lytro or for some other people. I would like to have this possibility to produce three-dimensional files for some objects from archaeology and art (see my post in the "General"-topic). Then the way will be open to "3D-print" such objects.



markus
Administrator
Posts: 68
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/19 23:35

Your desired application of LightField tech sounds very interesting!
To get maximum resolution files, you'll probably need to get a Lytro developer to enable direct conversion to .obj or .stl files, as most open-source software concentrates on the processed (and compressed) -stk.lfp files. While this may be entirely possible, it seems to me that Lytro is currently focussed (pun intended) on "more mainstream" features like Parallax and 3D.



Godehardt
newbie
Posts: 6
Re: Lightfield picture file to .obj or .stl format
on: 2012/09/20 14:42

Markus,
I will ask the people from Lytro whether they would agree to generate a obj file (together with a texture file) or a ply file which directly contains the texture (color) directly from the raw file. Is it possible to access the raw files from the camera? Or will only compressed files be sent from the camera to the computer?
Best regards, Erhard



markus
Administrator
Posts: 68
Re: Lightfield picture file to .obj or .stl format
on: 2012/10/05 05:52

Erhard, please excuse the delay.
Did you hear back from Lytro?
It is possible to access the raw files. The software will only show you the pictures themselves, but the raw files are accessible in your user directory (Windows: C\Users\..., Mac: Pictures Directory/...). Let me know if you need more help finding them.

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