“…Visual detecting of face has been studied extensively over the last decade. Face detection researchers summarized the face detection work into four categories: template matching approaches [Sakai, 1996] [Miao, 1999] [Augusteijn, 1993] [Yuille, 1992] [Tsukamoto, 1994]; feature invariant approaches [Sirohey, 1993]; appearance-based approaches [Turk, 1991] and knowledge-based approaches [Yang, 1994] [Yang, 2002] [ Kotropoulous, 1997]. Many researches also used skin color as a feature and leading remarkably face tracking as long as the lighting conditions do not varies too much [Dai, 1996], [Crowley, 1997] , [Hasanuzzaman 2004b].…”