1. A method for detecting a tailgating event in regard to security of a controlled access area, comprising: (a) acquiring one or more stereoscopic images of an area of observation; (b) analyzing the one or more images using a machine vision processing system to identify and classify a first object in the area of observation, said first object having supplied an authorization with respect to the controlled access area, and further using the machine vision processing system to identify and classify a second object in the area of observation; and (c) applying one or more access control rules to the information obtained from the image analysis to determine whether the second object is attempting to breach the controlled access area by utilizing the authorization supplied by the first object in violation thereof.