Understanding the color of human skin

The automated detection of humans in computer vision as well as the realistic rendering of people in computer graphics necessitates a better understanding of human skin reflectance. Prior vision and graphics research on this topic has primarily focused on images acquired with conventional color cameras. Although tri-color skin data is prevalent, it does not provide adequate information for explaining skin color (and its variations) or for discriminating between human skin and dyes designed to mimic human skin color. A better understanding of skin reflectance can be achieved through spectrographic analysis. Previous work in this field has largely been undertaken in the medical domain and focuses on the detection of pathology. Our work concentrates on the impact of skin reflectance on the image formation process. In our radiometric facility we measure the light reflected from the skin using a high resolution, high accuracy spectrograph under precisely calibrated illumination conditions. This paper presents observations from the first body of data gathered at this facility. From the measurements collected thus far, we have observed population-independent factors of skin reflectance. We show how these factors can be exploited in skin recognition. Finally, we provide a biological explanation for the existence of a distinguishing pattern in human skin reflectance.