Cameras can be coupled with other hardware, such as this camera from EMX International. They have integrated it with LRAD. LRAD allows the user to tell intruders to stay out of the area at extremely high volumes. But the sound is highly directional, so only the intruder hears the ultimatum. The above system has a daylight and thermal camera combination. There are several lens choices on the thermal camera and the 640 x 480 detector.
DMT radars detect and track the intruder, and its software automatically points the above system at the intruder and keeps it on them.