Scientists have created visual systems which they claim would help unmanned aircraft see for themselves as they fly fast and low over dangerous terrain.
Unmanned aircraft today have rapidly expanding roles ranging from mineral exploration, to military applications from scouting and intelligence gathering to interception. In future, they are expected to play an important role in the exploration of Mars.
Now, an international team, led by Queensland University, has developed the visual systems inspired by honey bees which can navigate accurately despite their tiny brains.
According to the scientists, the systems not only provides stereo vision to enable aircraft to see their way around obstacles in very low-level flight but also controls the aircraft's attitude by watching the horizon.
The team, led by Richard Moore, has developed a stereo system employing two cameras and two sophisticated, highly curved mirrors, for observing the terrain as it flows beneath the aircraft. The cameras feed back information on height and distance to the terrain and its obstacles in a steady flow.
"You know how things that are close seem to speed by, whereas things farther away seem to travel more slowly. Our design eliminates that distortion, enabling us to use the flow of optical data from all parts of the landscape in view to navigate the aircraft, even if it is moving fast," Moore said.
The system compares the blue colour of the sky with the red-green colours of the ground to detect whether the aircraft is pitching up or down, or rolling from side to side.
"It provides an absolute reference to where you are, unlike inertial guidance which infers it from the Earth's gravity. Trials show our method performs well in varied conditions of cloud, sun, altitude and different imaging systems, and is resistant to false horizon edges such as large trees, sky reflection from lakes or glare when the sun is in full view," he said.
The technology is designed to be incorporated into an existing aircraft visual system, or to be stand-alone.
Both systems have been developed to operate in daylight, but the researchers say they are capable of being adapted to infra-red and other forms of visual sensing for operation in the dark or low light. They are both lighter, cheaper and more efficient than radar-based sensing systems.
The systems will be unveiled for the first time at the International Conference on Intelligent Robots and Systems, in St Louis, USA from October 11-15.
