Image Analysis, Classification and Change Detection in Remote Sensing, 3rd Edition

2

Image St atistics

In a multispectral or a synthetic ap erture radar image , a given pixel value

g(i, j), derived from the measured radiation field at a satellite sensor, is never

exactly reproducible. It is the outcome of a c omplex measurement influenced

by instrument noise, atmospheric conditions, changing illumination and so

forth. It may be assumed, however, that there is an underlying random mech-

anism with an associated probability distribution which restricts the p ossible

outcomes in some way. Each time we make an observation, we ar e sampling

from that probability distribution or, put another way, we are observing a

different possible realization ...