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. Now, camera lenses with wide fields of view, such as fisheye lenses, create distortion around the edges of the image.
But that could change. 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 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.
Each small eye in the larger compound eye is made up of an independent corneal lens as well as a crystalline cone, which captures the light traveling through the lens. The number of ommatidia determines the resolution and varies widely among arthropods. Dragonflies, for example, have about 28,000 tiny eyes while worker ants have only in the neighborhood of 100.
Imitating the corneal lens-crystalline cone pairings, the camera created by Xiao and his colleagues has 180 miniature lenses, each of which is backed with its own small electronic detector. The number of lenses used in the camera is similar to the number of ommatidia in the compound eyes of fire ants and bark beetles.
Read the full press release here.