1. A method for optimum sensor layout for detecting an intruder, comprising: selecting, by a programmed computer device, candidate sensor locations within a representation of an area of regard; determining, by the programmed computer device, a sub-region of detection for each sensor based on a preset probability of detection of the intruder traversing a sub-region associated with each sensor; determining, by the programmed computer device, each pair of sensors with overlapping sub-regions of detection; determining, by the programmed computer device, a lowest probability of detection for any path between each pair of sensors with overlapping sub-regions of detection; and determining, by the programmed computer device, an optimum layout of sensor locations from the candidate sensor locations based on a path of the lowest probability of detection for any path between each pair of sensors with overlapping sub-regions of detection.