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
Facial expression have even shown that there are similarities between species in how emotions are expressed. Research has shown that chimpanzees are able to communicate many of the same facial expressions as humans through the complex movements of the facial muscles. In fact, the facial cues were so similar that Ekman's Facial Action Coding System could be applied to the chimps in evaluating their expressions. Of course, differences between the species' physical facial properties, such as white sclera and everted lips in chimps, would mean that some expressions could not be compared. Similarly, Darwin observed that infants' method of expression for certain