Distributions of Visibility Measures

In the present chapter we develop methods for determining the distributions of some measures of visibility for a given field of obstacles. We start first with the distribution of the number of targets which are simultaneously visible, out of m specified target points, either from one or from several observation points. This distribution is not the frequently encountered binomial distribution, since the visibility for specified targets are generally not independent, and the visibility probabilities are generally not the same. The other measure of visibility studied in this chapter is an integrated measure of the total length, of a specified star-shaped curve, that can be observed from one or several observation points. These measures have various applications.