Insect Eye View Inspired Camera
Insects can have a number of different types of eyes and are remembered more for their compound bulging eyes. In contrast with human eyes, insect eyes are immovable and unable to focus but have other advantages. When praying mantises, dragonflies, ants and other insects peer out at the world, their bulging, compound eyes allow them to see an incredibly wide field of view with an almost infinite depth of field. Imitating the functionality of an insect eye — which is really a collection of many tinier eyes, known as ommatidia — in a camera has been a long sought-after goal for engineers. Present day camera lenses with wide fields of view, such as fisheye lenses, create distortion around the edges of the image but future "insect eye" cameras may not.
The compound eyes of insects are composed of units called ommatidia. An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The outer part of the ommatidium is overlaid with a transparent cornea. The brain forms an image from these independent picture elements. The number of ommatidia in the eye depends upon the type of insect and ranges from just a handful to around 30 thousand in some dragonflies and moths.
In a paper published today in the journal Nature, a team of researchers including a University of Colorado Boulder engineer describes an experimental camera that can take exceptionally wide-angle photos without distorting the image.
To create the innovative camera the scientists used stretchable electronics and a pliable sheet of microlenses made from a material similar to that used for contact lenses.
The distortion inherent in conventional wide-angle lenses is a consequence of the mismatch of light passing through a hemispherically curved surface of the lens only to be captured by the flat surface of the electronic detector.
For the digital camera described in the new study, the researchers were able to create an electronic detector that can be curved into the same hemispherical shape as the lens, eliminating the distortion.
"The most important and most revolutionizing part of this camera is to bend electronics onto a curved surface," said Jianliang Xiao, assistant professor of mechanical engineering at CU-Boulder and co-lead author of the study. "Electronics are all made of silicon, mostly, and silicon is very brittle, so you can’t deform the silicon. Here, by using stretchable electronics we can deform the system; we can put it onto a curved surface."
The compound (convex or slightly curved) eyes of arthropods — animals with exoskeletons and jointed legs, including all insects as well as scorpions, spiders, lobsters and centipedes, among other creatures — typically have a lower resolution than the eyes of mammals, but they give arthropods a much larger field of view than mammalian eyes as well as high sensitivity to motion and an infinite depth of field. A goal for camera lenses.
For further information see Insect Lenses.
Compound Eye image via Wikipedia.