Hi, Bart,
I'm interested in the most basic techniques of using a single, 2D image as a basis for contriving a similar, yet disparate image to make a stereo pair which, by stereopsis, will yield a 3D effect.
A quick google search turned up this:
https://www.blender.org/I would note that almost all these applications probably apply mostly to motion picture work. And from my experience (as an observer, not an operator), a lot of outlining of picture elements (often by hand or mouse) is necessary for optimum results.
When creating left eye / right eye from only one eye, one needs to analyze each picture element, mask them, and be able to offset them individually for the second eye to place them in the correct depth. Also, these elements, when offset for the "new" eye will reveal background that was never photographed as it was previously covered by that element. So then one needs to recreate the background that was never photographed. Automated software may work ok on some images, but don't be surprised if a lot a manual labor also needs to be applied.
And lastly, this new "3d" image might look like flat cardboard cutouts in "3d space". The next step would be to create distortions in the elements to make them appear more rounded in the new 3d image. You've got your work cut out here... Good luck!