Insect Eyes Provide Inspiration for New Ultrathin Raspberry Pi-Compatible Array Camera System
By taking multiple images from the array and merging them, the ultrathin camera system can trade blows with much larger equivalents.
A team of researchers from the Korea Advanced Institute of Science and Technology (KAIST) and LIG Nex1's Unmanned/Robotic Systems Lab have created a Raspberry Pi-compatible ultrathin camera using arrayed microlenses inspired by the eyes of the adult strepsiptera Xenos peckii.
"The unique structures of biological vision systems offer intriguing inspiration for ultra-compact camera applications," the researchers write in the abstract to their paper. "Natural insects acquire sufficient visual information with small visual organs of tiny facet lenses. Furthermore, compound eyes have superior visual functions, such as large depth-of-field (DOF), wide field-of-view (FOV), high motion sensitivity, and low aberration.
"In particular, the eye structures of an adult Xenos peckii, exhibiting hundreds of photoreceptors on an individual eyelet, offer engineering inspiration for ultrathin camera or imaging applications because they have higher visual acuity than other compound eyes. For instance, Xenos peckii’s eye-inspired cameras provide an ~50 times higher spatial resolution than those from arthropod eyes, i.e., compound eyes with ommatidia. In addition, the effective image resolution of the Xenos peckii’s eye can also be further improved by the image overlap between neighbouring eyelets."
To prove the concept, the team created an ultrathin camera array based on multilayer aperture arrays (MAAs), inverted microlens arrays (iMLAs), and gap spacers, above a flat CMOS image sensor. While each lens in the array captures a relatively blurry image, the multiple images are combined into a finished shot that offers significantly improved clarity, contrast, and resolution than any single image.
The camera system was attached to a Raspberry Pi 3 Model B+ single-board computer, with the software required to combine the images running directly on board. Its performance was then compared to the Raspberry Pi Camera Module v2, an eight-megapixel traditional CMOS camera system — and the output is surprisingly close, considering that the prototype ultrathin camera system has a total track length of just 740μm.
"The ultrathin arrayed camera has successfully demonstrated high-contrast and high-resolution imaging by merging channel images based on the multi-frame super-resolution imaging method," the researchers claim. "Compared to commercial compact or mobile cameras, the ultrathin arrayed camera exhibits exceptional figures of merit, including image resolution, FOV [field of view], TTL [total track length] and cost-effectiveness. This novel ultrathin camera module provides new opportunities for diverse mobile, surveillance, or medical applications."
The team's work has been published under open-access terms in the journal Nature.