Physics-based modelling of human skin colour under mixed illuminants

Skin colour is an often used feature in human face and motion tracking. It has the advantages of being orientation and size invariant and it is fast t o process. The major disadvantage is that it becomes unreliable if the illu mination changes. In this paper, skin colour is modelled based on a reflect ance model of the skin, the parameters of the camera and light sources. In particular, the location of the skin colour area in the chromaticity plane is modelled for different and mixed light sources. The model is empirically validated. It has applications in adaptive segmentation of skin colour and in the estimation of the current illumination in camera images containing skin colour. (C) 2001 Elsevier Science B.V. All rights reserved.