Photometric Stereo: 3D Images of Human Faces.

Photo A. Blinov and M. Petrou

Maria Petrou of the Imperial College London and her colleagues further developed an imaging technique used to find flaws in industrial surfaces to capture 3D map of a human face:

The technique, called photometric stereo, uses a fixed digital camera and at least three lights placed around it to illuminate the face from different angles.

The lights are synchronized to flash very quickly in succession, in a few hundredths of a second, so the person being photographed only perceives one flash. But the computer picks up digital data for all lighting angles.

A program written by Petrou and her colleagues analyzes the shadows and highlights, and then combines them into one three-dimensional image.

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