Gait and Gait Recognition
We define gait to be the coordinated, cyclic combination of movements that result
in human locomotion. The movements are coordinated in the sense that they
must occur with a specific temporal pattern for the gait to occur. The movements
in a gait repeat as a walker cycles between steps with alternating feet. It is
both the coordinated and cyclic nature of the motion that makes gait a unique
phenomenon.
Examples of motion that are gaits include walking, running, jogging, and
climbing stairs. Sitting down, picking up an object, and throwing and object are
all coordinated motions, but they are not cyclic. Jumping jacks are coordinated
and cyclic, but do not result in locomotion.
Therefore, we define gait recognition to be the recognition of some salient
property, e.g., identity, style of walk, or pathology, based on the coordinated,
cyclic motions that result in human locomotion. In the case of biometric gait
recognition, the salient property is identity.We make the distinction between gait
recognition and what we call quasi gait recognition in which a salient property
is recognized based on features acquired while a subject is walking, but the
features are not inherently part of the gait. For example, skeletal dimensions may
be measured during gait and used to recognize an individual. However, skeletal
dimensions may be measured other ways, and are therefore not a property of
the gait.