The ability of humans to recognize gaits has long been of interest to psychologists.
Johansson [2, 3] showed that humans can quickly (in less than one second)
identify that a pattern of moving lights, called a moving light display (MLD),
corresponds to a walking human. However, when presented with a static image
from the MLD, humans are unable to recognize any structure at all. For example,
without knowing that the dots in a single frame of the sequence shown in
Fig. 1 are on the joints of a walking figure, it is difficult to recognize them as
such. What we cannot show in a print medium is, that within a fraction of a
second after the dots move, one can recognize them as being from a human gait.
Johansson’s contributions are important because they provide an experimental
method that allows one to view motion extracted from other contextual information.
With the context removed, the importance of motion becomes obvious.
Johansson also suggests a set of gestalt rules that humans use to connect the
moving dots and infer structure.
Bertenthal and Pinto [4] identify the following three important properties in
the human perception of gaits.