Researchers create miniature wide-angle camera with flat metalenses
New design could enable high-quality wide-angle cameras that can possibly
fit into smartphones
Date:
April 14, 2022
Source:
Optica
Summary:
Researchers have designed a new, ultrathin camera that acquires
wide- angle, high-quality images using a metalens array. This
approach eliminates bulky and heavy lenses, possibly enabling the
incorporation of wide-angle cameras into smartphones and other
portable imaging devices.
FULL STORY ========================================================================== Researchers have designed a new compact camera that acquires wide-angle
images of high-quality using an array of metalenses -- flat nanopatterned surfaces used to manipulate light. By eliminating the bulky and heavy
lenses typically required for this type of imaging, the new approach
could enable wide-angle cameras to be incorporated into smartphones and portable imaging devices for vehicles such as cars or drones.
==========================================================================
Tao Li and colleagues from Nanjing University in China report their
new ultrathin camera in Optica, Optica Publishing Group's journal for high-impact research. The new camera, which is just 0.3 centimeters thick,
can produce clear images of a scene with a viewing angle of more than
120 degrees.
Wide-angle imaging is useful for capturing large amounts of information
that can create stunning, high-quality images. For machine vision
applications such as autonomous driving and drone-based surveillance, wide-angle imaging can enhance performance and safety, for example by
revealing an obstacle you couldn't otherwise see while backing up in
a vehicle.
"To create an extremely compact wide-angle camera, we used an array of metalenses that each capture certain parts of the wide-angle scene,"
said Li.
"The images are then stitched together to create a wide-angle image
without any degradation in image quality." Miniaturizing the wide-angle
lens Wide-angle imaging is usually accomplished with a fish-eye
compound lens or other type of multilayer lens. Although researchers
have previously tried to use metalenses to create wide-angle cameras,
they tend to suffer from poor image quality or other drawbacks.
In the new work, the researchers used an array of metalenses that
are each carefully designed to focus a different range of illumination
angles. This allows each lens to clearly image part of a wide-angle object
or scene. The clearest parts of each image can then be computationally
stitched together to create the final image.
"Thanks to the flexible design of the metasurfaces, the focusing and
imaging performance of each lens can be optimized independently," said
Li. "This gives rise to a high quality final wide-angle image after
a stitching process. What's more, the array can be manufactured using
just one layer of material, which helps keep cost down." Seeing more
with flat lenses To demonstrate the new approach, the researchers used nanofabrication to create a metalens array and mounted it directly to a
CMOS sensor, creating a planar camera that measured about 1 cm x 1 cm x
0.3 cm. They then used this camera to image a wide-angle scene created
by using two projectors to illuminate a curved screen surrounding the
camera at a distance of 15 cm.
They compared their new planar camera with one based on a single
traditional metalens while imaging the words "Nanjing University"
projected across the curved screen. The planar camera produced an image
that showed every letter clearly and had a viewing angle larger than
120DEG, more than three times larger than that of the camera based on
a traditional metalens.
The researchers note that the planar camera demonstrated in this research
used individual metalenses just 0.3 millimeters in diameter. They plan
to enlarge these to about 1 to 5 millimeters to increase the camera's
imaging quality.
After optimization, the array could be mass produced to reduce the cost
of each device.
========================================================================== Story Source: Materials provided by Optica. Note: Content may be edited
for style and length.
========================================================================== Related Multimedia:
* High-quality_wide-angle_images_from_compact_camera ========================================================================== Journal Reference:
1. Ji Chen, Xin Ye, Shenglun Gao, Yuxin Chen, Yunwei Zhao, Chunyu
Huang, Kai
Qiu, Shining Zhu, Tao Li. A planar wide-angle-imaging camera
enabled by metalens array. Optica, 2022; DOI: 10.1364/OPTICA.446063 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220414110719.htm
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