Registration of infrared and visible-spectrum imagery for face recognition

A method is proposed to register visible and infrared face images. The vanishing-point based approach [J.G. Wang and E. Sung, 2001] is applied to the visible image to determine the 3D pose of the human head. Then the corresponding pose with respect to the infrared camera is computed through the known relationship by calibration between the visible and infrared cameras. By doing so, the skin temperature range within the infrared image can be superimposed over the visible face image. We use the EM strategy to first compute the 3D pose using some initially learned (PCA) model parameters, and then update iteratively the parameters for individual persons and their facial expressions till convergence. The EM technique models data uncertainty using Gaussian mixtures defined over positions and orientation of facial plane. The resulting weighted parameters estimation problem is solved using the Levenberg-Marquardt method. The results on the synthetic data and real images have verified the performance of the approach.