Binary images appear in various pattern recognition applications. It is thu
s important to design pattern recognition algorithms that are optimal for s
uch images. We address the problem of target location in binary images pert
urbed with nonhomogeneous background noise. The proposed algorithm optimize
s the likelihood ratio between the hypotheses that the target is present wi
thin a small subwindow of the image and that it is not present in this subw
indow. The algorithm is shown to consist of two correlation operations and
a few pointwise nonlinear transformations. With numerical simulations, we i
llustrate the efficiency of this technique, especially in the presence of s
trongly nonhomogeneous background noise. (C) 1998 Optical Society of Americ
a [S0740-3232(98)00812-6].