An image background maintenance system and method for maintaining a
background model of an image sequence by processing on multiple spatial
scales. These multiple spatial scales include a pixel scale, a regional
scale and a frame scale. The image sequence undergoes pixel processing
that determines a current background model and provides an initial pixel
assignment as either a background or a foreground pixel. Region
processing further refines the initial pixel assignments by considering
relationships between pixels and possibly reassigning pixels. Frame
processing further refines the current background model by determining
whether a substantial change has occurred in the actual background and,
if so, providing a more accurate background model.