Here are the three face recognition algorithms available in OpenCV v2.4.1:
• FaceRecognizer.Eigenfaces: Eigenfaces, also referred to as PCA, first used by Turk and Pentland in 1991.
• FaceRecognizer.Fisherfaces: Fisherfaces, also referred to as LDA, invented by Belhumeur, Hespanha and Kriegman in 1997.
• FaceRecognizer.LBPH: Local Binary Pattern Histograms, invented by Ahonen, Hadid and Pietikäinen in 2004.