Using the Viola—Jones face detection algorithm, faces can be detected in an image using these Haar-like features. Each Haar-like feature is only a weak classifier, and hence a large number of Haar-like features are required to detect a face with good accuracy. A huge number of Haar-like features are computed for all possible sizes and locations of each Haar-like kernel using the integral images. Then an AdaBoost ensemble classifier is used to select important features from the huge number of features and combine them into a strong classifier model during the training phase. The model learned is then used to classify a face region with the selected features.
Most of the regions in an image ...