Let be a set of sites and be
the phase space. Furthermore, we write as
a sequence of image (configuration) vectors taken at time ,
, where .
Note that, in the problem of interest here, . We assume
that satisfies MRF properties with a Gibbs potential
. Note that are NIMs of the scene. These will
be used extensively in our discussion. Due to noise, we cannot
observe directly. Instead, we observe noisy images (NIs)
that are given by