An intruder has entered a prohibited area on a pitch-dark night. Little does he know he is being watched, invisibly and silently, by a drone, 120m above, using a thermal infrared camera that picks up his body heat and movement.
Security gets an alert and within seconds a team arrives, sending another night-seeing eye - a dog - to intercept the trespasser.
This isn't a crime movie or a futuristic simulation but real video footage from a mine outside Johannesburg.
South African companies and the government are using drones fitted with thermal cameras to combat crime.
The tech is in place on mines, at container depots, following trains and monitoring railway networks. Drones also do engineering and environmental checks on, among other things, vineyards and avocado plantations.
UAV & Drone Solutions, a local innovator in drone technology, was one of the first operators to be awarded a commercial licence, initially to track rhinos and reduce poaching. Co-directors Georges Sayegh, Robert Hannaford and Otto Werdmuller say drones will change our lives, and their focus has broadened beyond wildlife conservation.
Werdmuller says the technical applications are limitless. Medicine drops in danger zones, assisting in hostage situations ... even pizza and online shopping deliveries will be revolutionised.
Braam Botha, head of operations at Cape Town-based UAV Industries, a commercial drone operator and drone pilot training academy, says that apart from wildlife surveillance his company has conducted night-vision security research for agricultural purposes and provided aerial security at live events - including shark-spotting at surfing contests.
HUMAN MOVEMENT
But there are two impediments, says Werdmuller. "Legislation and safety. What is technically possible in an urban environment is unlimited. But our legislation is solid. Privacy is controlled. The safety issues include that a drone is heavy machinery, and it can fall out of the sky and hurt people. So no, they won't be flying around like mosquitoes in the near future. Invasiveness is a massive issue and people who operate drones as a hobby are not always responsible with this technology."
In the company workshop, Sayegh shows off new rotor blades that have just arrived. These will give the drone more flight time. The previous blades were heavier and double the size.
"Small and light electric-powered drones, especially fixed-wing aircraft, make little noise and are often bird-shaped, meaning animals on the ground are rarely disturbed by these tools, if they notice them at all," says Sayegh.
Criminals are equally unaware...