There are three maintenance schemes:
The blind background maintenance consists to update all the pixels with the same rules.The disadvantage of this scheme is that the value of pixels classified as foreground are taken into account in the computation of the new background and so polluted the background image.
Selective maintenance consists to update the pixel with a different learning rate following its previous classification into foreground or background.
Fuzzy adaptive maintenance consists to update the pixel with a learning rate which depends on the membership of the pixel to the class foreground or background.