Unlike other gait representations which consider gait as a
sequence of templates (poses), GEI represents human motion
sequence in a single image while preserving temporal
information. In comparison to the gait representation by binary
silhouette sequence, GEI not only saves storage space and
computation time but also it is less sensitive to silhouette noise in
individual frames and we do not need to consider the time
moment of each frame. GEIs reflect major shapes of silhouettes
and their changes over the gait cycle. Gait Energy Image (GEI) is
the sum of images of the walking silhouette divided by the
number of images.It accounts for human walking at different
speeds. It is referred as the gait energy image because