Facial recognition system introduced varying technologies to the procedure. Some of the most notable include the following techniques: Some face recognition algorithms identify facial features by extracting landmarks, or features, from an image of the subject's face. For example, an algorithm may analyze the relative position, size, and/or shape of the eyes, nose, cheekbones, and jaw. These features are then used to search for other images with matching features. Other algorithms normalize a gallery of face images and then compress the face data, only saving the data in the image that is useful for face recognition. A probe image is then compared with
Forensic facial reconstruction of facial features, and other available reconstructions. These computer approximations are usually most effective in victim identification because they do not appear too artificial. This method has been adapted by the National Center for Missing & Exploited Children, which uses this method often to show approximations of an unidentified decedent to release to the public in hopes to identify the subject. Superimposition is a technique that is sometimes included among the methods of forensic facial reconstruction. It is not always included as a technique because investigators must already have some kind of knowledge about the identity of the skeletal remains