1/19/2011
Researchers from the University of Illinois and Northwestern University are the first to develop a curvilinear camera, much like the human eye, with the significant feature of a zoom capability, unlike the human eye.
Written by
Researchers from the University of Illinois and Northwestern University are the first to develop a curvilinear camera, much like the human eye, with the significant feature of a zoom capability, unlike the human eye.
"This provides a key piece of missing functionality for the original camera concept," explained John Rogers, the Lee J. Flory Founder Chair in Engineering and professor of materials science and engineering at Illinois. "The result is a complete camera system, with tunable lens and tunable detector, capable of taking pictures."
While the camera won't be appearing at Best Buy any time soon, the tunable camera—once optimized—should be useful in many applications, including night-vision surveillance, robotic vision, endoscopic imaging, and consumer electronics.
The research will be published the week of Jan. 17 by the Proceedings of the National Academy of Sciences (PNAS). Rogers, who led the design, experimental, and fabrication work, is a co-corresponding author of the paper along with his colleague, Yonggang Huang, the Joseph Cummings Professor of Civil and Environmental Engineering and Mechanical Engineering at Northwestern's McCormick School of Engineering and Applied Science.
"We were inspired by the human eye, but we wanted to go beyond the human eye," Huang said. "Our goal was to develop something simple that can zoom and capture good images, and we've achieved that."
The tiny camera combines the best of both the human eye and an expensive single-lens reflex (SLR) camera with a zoom lens. It has the simple lens of the human eye, allowing the device to be small, and the zoom capability of the SLR camera without the bulk and weight of a complex lens. The key is that both the simple lens and photodetectors are on flexible substrates, and a hydraulic system can change the shape of the substrates appropriately, enabling a variable zoom.
Earlier eyeball camera designs are incompatible with variable zoom because these cameras have rigid detectors. The detector must change shape as the in-focus image changes shape with magnification. Huang and Rogers and their team use an array of interconnected and flexible silicon photodetectors on a thin, elastic membrane, which can easily change shape. This flexibility opens up the field of possible uses for such a system. (The array builds on their work in stretchable electronics.)
The camera system also has an integrated lens constructed by putting a thin, elastic membrane on a water chamber, with a clear glass window underneath. Initially both detector and lens are flat. Beneath both the membranes of the detector and the simple lens are chambers filled with water. By extracting water from the detector's chamber, the detector surface becomes a concave hemisphere. (Injecting water back returns the detector to a flat surface.) Injecting water into the chamber of the lens makes the thin membrane become a convex hemisphere.
To achieve an in-focus and magnified image, the researchers actuate the hydraulics to change the curvatures of the lens and detector in a coordinated manner. The shape of the detector must match the varying curvature of the image surface to accommodate continuously adjustable zoom, and this is easily done with this new hemispherical eye camera.
The National Science Foundation supported the research. The paper is titled “Dynamically tunable hemispherical electronic eye camera system with adjustable zoom capability.” In addition to Rogers and Huang, other authors of the paper are Chaofeng Lu and Ming Li, from Northwestern; Inhwa Jung, Jianliang Xiao, Viktor Malyarchuk and Jongseung Yoon, from the University of Illinois; and Zhuangjian Liu, from the Institute of High Performance Computing, Singapore.
____________________
Contact: John Rogers, Department of Materials Science and Engineering, 217/244-4979.
The original text of this article was developed and distributed by the Robert R. McCormick School of Engineering and Applied Science, Northwestern University, 847/491-5220.
Photo: John Rogers
If you have any questions about the College of Engineering, or other story ideas, contact Rick Kubetz, editor, Engineering Communications Office, University of Illinois at Urbana-Champaign, 217/244-7716.