Facial Normal Map Capture using Four Lights : an Effective and Inexpensive Method of Capturing the Fine Scale Detail of Human Faces using Four Point Lights

Obtaining photorealistic scans of human faces is both challenging and expensive. Capturing thehigh-frequency components of skin surface structure requires the face to be scanned at very highresolutions, outside the range of most structured light 3D scanners.We present a novel and simple enhancement to the acquisition process, requiring only four photo-graphic  ash-lights and three texture cameras attached to the structured light scanner setup.The three texture cameras capture one texture map (luminance map) of the face as illuminatedby each of the four  ash-lights. Based on those four luminance textures, three normal maps ofthe head are approximated, one for each color channel. Those normal maps are then used toreconstruct a 3D model of the head at a much higher mesh resolution, in order to validate thenormals. Finally, the validated normals are used as a normal map at rendering time. Alternatively,the reconstructed high resolution model can also be used for rendering.