Pre - processing Step 5 – Classification Step 3 –

Gait has few important advantages over other forms of biometric identification. It can be acquired at a distance when other biometrics are obscured or the resolution is insufficient. It does not require subject cooperation and can be acquired in a noninvasive manner. It is easy to observe and hard to disguise as walking is necessary for human mobility. Gait can be acquired from a single still image or from a temporal sequence of images (e.g., a video). Shakespeare made several references to the individuality of gait, e.g., in The Tempest [Act 4 Scene 1], Cares observes “High’st Queen of state, Great Juno comes; I know her by her gait” and in Henry IV Part II [Act 2, Scene 3], “To seem like him: so that, in speech, in gait, in diet, in affections of delight, in military rules, humors of blood, he was the mark and glass, copy and book.” The aim of medical research has been to classify the components of gait for the treatment of pathologically abnormal patients. Murray et al. [17] created standard movement patterns for pathologically normal people. Those patterns were then used to identify pathologically abnormal patients. The biomechanics literature makes observations concerning identity: “A given person will perform his or her walking pattern in a fairly repeatable and characteristic way, sufficiently unique that it is possible to recognize a person at a distance by their gait” [27]. Psychophysiological studies such as [5, 11] have shown that humans can recognize friends and the sex of a person solely by their gait with 70–80 % accuracy. These and similar studies have inspired the use of gait as a biometric trait.