(a) shows capturing a foreground
silhouette of the moving object or person. As the person or object moves,
copying the most recent foreground silhouette as the highest values in the
motion history image creates a “layered history” of the resulting motion.
Typically, this “highest value” is just a floating-point timestamp of time
since the code has been running in milliseconds. Figure
(b) shows the result that may be called
Motion History Image
. The MHI in Figure
represents how the motion took place. A pixel
level or a time delta threshold, as appropriate, is set such that pixel
values in the MHI that fall below that threshold are set to zero.