[Bf-committers] 2d Image to 3d?

[Jonathan Merritt]

Austin Benesh wrote:

> Would it be too much work to write a sub-routine that takes three 
> parts of an orthographic image (top, bottom, side) and turns them into 
> a mesh? Would it even be possible?
>

This is difficult for two reasons:
    1. Photographic cameras do not take orthographic images.
    2. For triangulation (either in orthographic or perspective 
projections), you need to have points visible in at least two views.  
When you take photographs of most real objects, they have occlusion of 
enough feature points to make any kind of straightforward approach 
thoroughly impractical.

I do have a solution, however:
    http://blix.sourceforge.net/

It's a BPy script and Python extension that does the following:
    1. Camera calibration (ie: proper calibration of a perspective 
camera).  This places a virtual camera at the correct location and 
orientation relative to a calibration object, and gives it the correct 
'lens' value.
    2. Digitizing of feature points from multiple calibrated views.
    3. Rigid-body orientation, to match up multiple digitizing sessions.

I presented this system in December last year at the 5th Australasian 
Biomechanics Conference:

Merritt, J.S., Burvill, C. and Davies, H.M.S. (2004) "An In-Vitro 
Stereophotogrammetric Technique for Constructing Surface Models of Whole 
Bones." in Proceedings of the Fifth Australasian Biomechanics Conference.

The system is poorly documented (VERY poorly documented), and very 
manual at the moment.  However, it can be used if you're willing to 
spend a half day or so figuring it out.  Here's an example of a bone 
digitized using this method:
    http://www.warpax.com/temp/mc3-example.png

Yes, this could be coded directly in Blender (ie: in C, not in Python).  
Alas, I don't have time for it at the moment, since it's a part of my 
PhD that is basically "finished", and I need to spend all of my time 
working on other things just now.

-- 
Jonathan Merritt BE(Mech)/BSc
PhD Student - Equine Biomechanics
The University of Melbourne
Veterinary Clinical Centre, Werribee