Preprocessing of Face Images: Detection of Features and Pose Normalization

The reliability, speed, and complexity of virtually any face recognition system are substantially improved if the location and the scale of the faces are known. We propose a method for automatic and robust detection of the eyes and mouth using the context free generalized symmetry transform and knowledge of faces. The features are extracted from the image of the intensities gradients and are then used to normalize the face images. We show that a normalization procedure based on affine transformations whose anchor points are the locations of the eyes and mouth substantially increases the effectiveness of general purpose classification techniques in face recognition. Other normalization procedures for avoiding the effect of background and varying light conditions are proved to be instrumental as well.