01.jpg (21.71 KB. 530x298 - viewed 2 times.)Researchers have used the human eye as inspiration for a new type of camera
that boasts the simple lens system of the eye, but features the variable zoom
capability of a single-lens reflex (SLR) camera without the bulk and weight of a
complex lens system. As a result, the “eyeball camera” measures less than an
inch in diameter, is inexpensive to make and should be suited to a variety of
applications, including night-vision surveillance, robotic vision systems,
endoscopic
imaging and consumer electronics.
Developed by researchers from Northwestern University and the University of
Illinois at Urbana-Champaign, the first of its kind curvilinear camera overcomes
the problem of previous eyeball camera designs that were incompatible with
variable zoom. This was because they used rigid detectors, but because the
image changes shape with magnification, the detector must also change shape
to keep the image in focus.
To achieve this the researchers used an array of interconnected and flexible
silicon photodetectors on a thin, elastic membrane, which can easily change
shape. Additionally, the camera system also has an integrated “liquid lens”
constructed by putting a thin, elastic membrane on a water chamber, with a
clear glass window underneath.
Initially the chambers beneath the membranes of the detector and the lens
are filled with water, making both the detector and the lens flat. But as water
is extracted from the detector’s chamber, the detector surface becomes a
concave hemisphere. Meanwhile, injecting water into the lens chamber makes
the thin membrane become a convex hemisphere.
By controlling the hydraulics to change the curvatures of the lens and detector
in a coordinated way to ensure the shape of the detector matches the varying
curvature of the image surface, the camera is able to produce an in-focus and
magnified image. The camera developed by the researchers currently has a
3.5x optical zoom, but they say a higher zoom is possible using the technology.
“We were inspired by the human eye, but we wanted to go beyond the human
eye,” said Yonggang Huang, Joseph Cummings Professor of Civil and Environmental Engineering and Mechanical Engineering at Northwestern’s McCormick School of Engineering and Applied Science. “Our goal was to develop somethingsimple that can zoom and capture good images, and we’ve achieved that.”
