Facial Landmark Localization

Face detection and recognition is a vibrant area of biometrics with active research and commercial efforts over the last 20 years. The task of face detection is to search faces in images, reporting their positions by a bounding box. Recent studies [19, 31] have shown that face detection has already been a state-of-the-art technology in both accuracy and speed. However, face detection is not sufficient to acquire facial landmarks, for example, eye contours, mouth corners, nose, eyebrows, etc. This is therefore the task of facial landmark localization which aims to find the accurate positions of the facial feature points as illustrated in Fig. 12.1. It is a fundamental and significant work in face-related areas, for example, face recognition, face cartoon/sketch, face pose estimate, model-based face tracking, eye/mouth motion analysis, 3D face reconstruction, etc. There is a wide variety of works related to facial landmark localization. The early researches extract facial landmarks without a global model. Facial landmarks, such as the eye corners and centers, the mouth corners and center, the nose corners, chin and cheek borders are located based on geometrical knowledge. The first step consists of the establishment of a rectangular search region for the mouth and a rectangular search region for the eyes. The borders are extracted by applying corner detection algorithm such as SUSAN border extraction algorithm [17]. Such methods are fast, however, they could not deal with faces of large variation in appearance due to pose, rotation, illumination and background changes.