Image Relighting

Hewlett Packard have developed an interesting photographic technique that is being used by archeologists, although it could have interesting uses for other applications. It involves taking multiple images of the same subject under various lighting conditions by moving and changing the intensity of the light. These images are then merged together into a Polynomial Texture Map which represents how the subject responds to light. This allows photograph to be re-light in software showing up features normally invisible to the naked eye.

HP's Relighting page
Demonstrations