Insect eye inspires ultra-thin image sensor
By IANS,
Washington : The amazing versatility of an insect's compound eye has inspired researchers worldwide into working on ultra-thin imaging systems.
Features of these compound eyes, optimised over millions of years of evolution, are being adapted for present-day imaging equipment.
Accordingly, scientists at the Fraunhofer Institute for Applied Optics and Precision Engineering, are working on the development of an ultra-thin image sensor.
For example Andreas Brückner, working on his doctoral thesis, improved the imaging properties of these sensor applications.
Insects have not just two, but thousands of eyes. Each facet of their eye picks up one image point, and the numerous facets, each with its own lens and visual cells, are spread over the surface of a hemisphere.
Consequently, the insect eye can cover a wide viewing angle - but the resolution of their images is not particularly clear.
This is surprising, given that insects can fly very precise manoeuvres. They are able to do so because of the principle of hyperacuity -- insects see more than the images actually captured by their compound eyes because the visual fields of adjacent facets overlap -- and Andreas Brückner is replicating this phenomenon in a technical system.
“The aim was to develop micro-optical compound eyes which contain numerous parallel imaging channels and which are also extremely compact, thinner than 0.5 mm,” said Brückner.
He began by analysing how images are created in artificial compound eyes. Given that each facet captures one image point, the challenge was to accomplish controlled overlapping in the technical system.
With a precise knowledge of the angular sensitivity, image signals of adjacent facets can then be compared with one another. This makes it possible to determine the position of the object viewed in a two-dimensional visual field with accuracy many times higher than the image resolution.
Consequently, the sensor can recognize simple objects, precisely determine their position and size, and also reliably detect movements.
Several projects are already underway to implement the process, for instance as solar altitude sensors in automobiles, for recognising traffic lanes in driver assistance systems, and in machine vision.