Tactical aspects of search and rescue operations

In search and Rescue operations, a team of rescuers sweep a rectangular area, following parallel paths at a distance [delta] from each other, looking for a lost individual. For a given [delta], the Probability of Detection is the probability that the sweep will be successful. This function of [delta] is an essential ingredient to the tactical aspects of rescue operations. We call the set of points that can be seen from a particular location a vision set. We show how the distribution of vision set width determines the Probability of Detection function and how it determines the spacing [delta] minimizing the expected search time.