Bump/displacement map from single image (algorithm)

category: gfx [glöplog]
Hi guys!

I was wondering if anyone here knows what is the magic behind computing a bump map from single image like in CrazyBump, ShaderMap or other tools? How does this filter work? I know its just a fake approximation, but hey - it works very well and looks nice in most cases!

I was trying to google a little bit, but haven't found anything useful at all, except for a lot of PDF papers talking about depth extraction in stereoscopy, and rough depth extraction from natural images (ugly as hell, looks totally useless for the case of simple textures)... and one called "The Extraction of Depth Structure from Shading and Texture in the Macaque Brain", great!

So, I was thinking if it is just a composition of very basic filters or does it involve some heavy computation tasks with neural networks, FFTs, pattern recognition, etc.?

Thanks a lot for any hint!

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added on the 2010-08-19 10:22:19 by PiN PiN