Bio-robotic Vision
Australian scientists are studying how bees see the world in order to design a robotic helicopter which can fly by itself. They have observed that when a bee sets out from its hive in search of food, it can travel almost 10 kilometres. Having found food it knows exactly where to go to return home to the hive. In fact, it makes a beeline back home. The question baffling scientists is how their tiny direction-finding organisms work. A bee’s brain is the size of a sesame seed and has significantly fewer neurones than a human brain. But having learnt what clever tricks these intelligent insects use to see and navigate in the world, scientists have redesigned a radio-controlled crop-dusting helicopter so that it can find its own way around the world without a pilot and no one at the controls.
The brains of this helicopter consist of a sophisticated Pentium III on-board computer which can be programmed or directed as it flies. Its eyes are a tiny camera with special mirrors which assist it with navigation. They have called this device a hat mirror because it is shaped like a Mexican hat. The device, the hat mirror, consists of two main mirrors: a panoramic mirror at the top and a circular mirror at the bottom. The latter does the stereo imaging between the two mirrors. There is another secondary, less important mirror. Its purpose is to reflect all light from the two mirrors to the top and then back down into a hole where a video camera sits inside the mirror.
This hat mirror gives the helicopter all-round vision or a panoramic view just like for an insect which has 360˚vision of the horizon at all times. The horizon, in actual fact, maps onto a small circle in an image created by the hat mirror and, keeping the horizon circle centred in the mirror assures stability. This is important because it gives attitude from the horizon – in other words, it registers which way is up. One other thing that vision gives is a sense of distance to objects. Being able to look at the image motion, it is possible to work out the distance to objects all around, thus making sure of not flying into them.
