We hear about drones being used to do a lot of things, but the creation of art is one that doesn't come up too often. That could be about to change, though, as a computer scientist from Montreal's McGill University has been using tiny quadcopters to paint portraits on the campus' hallway walls. Down the road, he hopes that larger drones could be used to create murals high up on the sides of buildings, or in other hard-to-reach locations.

For the past two years, Prof. Paul Kry has been using mini-drones armed with ink-dipped sponge tips to create portraits of people such as Alan Turing, Grace Kelly, and Che Guevara.

The aircraft use a technique known as stippling, in which complete images are made up of an array of individual dots. A computer remote-control system uses a motion-capture camera and custom algorithms to plan the drones' flight paths, and to make corrections as errors occur – these can be caused by factors such as breezes in the hallways, that send the copters slightly off-course.

The portraits done so far range in complexity from 400 to over 2,000 dots. Of course, the drones have to periodically stop to get fresh batteries, and to have their sponge tips re-inked. To that end, Kry has been looking into tethering the quadcopters to an AC power supply, so no battery changes are necessary. He's also trying a wall-mounted ink pot, that the copters can dab their sponges in at regular intervals.

Ultimately, though, he'd like to see the technology go bigger.

"There's this wonderful mural festival in Montreal, and we have giant surfaces in the city that end up getting amazing artwork on them," he says. "If we had a particularly calm day, it would be wonderful to try to do something on a larger scale like that."

More information is available in the video below.