1. A security system for detecting the presence of one or more persons in a location to be monitored, said system comprising: (i) one or more light sources directed in the direction of said location; (ii) one or more light detectors for detecting reflections of said one or more light sources from said one or more persons to form an image representing eyes of said one or more persons; (iii) a scanning module to direct said one or more light sources and said one or more light detectors at narrow portions of said location at a time, capturing an image of said narrow portion of said location; (iv) a mechanical bracket on which said one or more light sources and said one or more light detectors are mounted; (v) a scanning controller for driving said scanning module, said scanning controller moving said one or more light sources together with said one or more light detectors, on said mechanical bracket, to a new position after each image of said narrow portion of the location is captured; (vi) a joining module for combining said captured images of said narrow portions of said location to form a single image of said location; and (vii) a processing unit for analyzing said single image to identify and count the number of eyes on said single image.