**3. Local Approaches**

In the context of face recognition, local approaches treat only some facial features. They are more sensitive to facial expressions, occlusions, and pose [1]. The main objective of these approaches is to discover distinctive features. Generally, these approaches can be divided into two categories: (1) local appearance-based techniques are used to extract local features, while the face image is divided into small regions (patches) [3,32]. (2) Key-points-based techniques are used to detect the points of interest in the face image, after which the features localized on these points are extracted.
