Three-dimensional shape and two-dimensional surface reflectance contributions to face recognition: an application of three-dimensional morphing

We measured the three-dimensional shape and two-dimensional surface reflect ance contributions to human recognition of faces across viewpoint. We first divided laser scans of human heads into their two- and three-dimensional c omponents. Next, we created shape-normalized faces by morphing the two-dime nsional surface reflectance maps of each face onto the average three-dimens ional head shape and reflectance-normalized faces by morphing the average t wo-dimensional surface reflectance map onto each three-dimensional head sha pe. Observers learned frontal images of the original, shape-normalized. or reflectance-normalized faces, and were asked to recognize the faces from vi ewpoint changes of 0, 30 and 60 degrees. Both the three-dimensional shape a nd tao-dimensional surface reflectance information contributed substantiall y to human recognition performance, thus constraining theories of face repr esentation to include both types of information. (C) 1999 Elsevier Science Ltd. All rights reserved.