'Eagle eye' lenses may inspire hi-def cameras as thin as a strand of hair
As anyone who has bought a smartphone in the last few years can tell you, cameras are getting smaller and smaller. Now, miniature lenses that mimic the eyes of predatory birds could shrink a camera's size to less than 1/100th of an inch — and in the meantime, revolutionize a host of compact technologies.
The lens structures were created by physicist Harald Giessen and his colleagues at the University of Stuttgart in Germany. They turned to bird vision because eagle and falcon eyes create a picture that is highly detailed in the center, while the surrounding area is blurrier.
"If you take a snapshot with your smartphone, and you want to magnify it, you cannot see the details anymore because they are pixelated," said University of Stuttgart physicist Harald Giessen. "Using our sensor, you can zoom into the image without losing anything, because of the higher density of pixels."
Using ultrathin plastic and a 3-D printer, their experimental lenses are printed directly onto a sensor from a Raspberry Pi camera. The lenses are arranged in small clusters and range from wide to narrow angles. The printer uses laser pulses — that last just one quadrillionth of a second — to melt and shape the plastic into the perfect lens. A similar manufacturing technique is used to make modern dental implants.
"The printer costs well over 400,000 Euros ($429,000)" said Giessen. "So it's not something that you can get at your local computer store."
The pictures produced by the camera are foveated, a reference to the part of the eye that's responsible for detailed vision. Foveation in this case means that the focus varies in different points on the same picture.
This imaging technique has a range of benefits, such as reducing the computer processing power needed for virtual reality hardware and generating thumbnails for satellite imagery.
Tests performed by the researchers show that their compact, birdeye lenses had higher clarity than a comparable single lens.
One current limitation is the speed of manufacturing. The intricate process of shaping each lens takes between 15 minutes and a few hours, depending on the size, and the end result may still have imperfections.
"A key challenge, as recognized by the authors, is the fabrication time and cost, making mass production difficult at the moment." said Yizheng Zhu, a physicist at Virginia Tech who wasn't involved in the study. "Hopefully, as technology advances, more improvements can be made in this area."
"The strength of this demonstration lies in the fact that they have proved miniaturization and functionality while producing strong image quality." said Gregory Quarles, chief scientist of the Optical Society who wasn't involved with this study. Quarles says that the next steps for this technology would be to determine the benefits these lenses have over conventional cameras in terms of cost and image quality.
These cameras could be used in self-driving cars and smart glasses, Giessen said, to make highly detailed scans of the world around them.
Editor's note: This article has been corrected to indicate that foveated refers to the part of the eye that's responsible for detailed vision.