### An approximation of the κ-function for the study of binary images.

Jensen et al. (1990) gave an exact expression for the κ-function in non-overlapping Boolean models. The present study proposes and evaluates an approximate expression for the κ-function in overlapping isotropic Boolean models based on an approximation of the covariogram of the primary grain. We study the suitability of a Boolean model for two binary images using this approximate expression.