• Researchers create miniature wide-angle

    From ScienceDaily@1:317/3 to All on Thu Apr 14 22:30:46 2022
    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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