Yeah it's the second case I was interested in. It looks like the algorithm generates a best fit normal map based on the various lighting profiles - presumably

Yeah it's the second case I was interested in. It looks like the algorithm generates a best fit normal map based on the various lighting profiles - presumably it must be told which direction the light is coming from. I do a lot of research work with stereo, so thanks for the link! Have to give that a go sometime :)