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  • Image Compression Breakthrough?

    By JOHN MARKOFF

    Using a new class of artificial materials, scientists at Duke University have designed a sensor that compresses images far more efficiently than existing technologies like JPEG.

    The materials, called metamaterials, have exotic qualities that bend light, X-rays and radio waves in unusual ways.

    While they are barely a decade old, they are fast falling in cost and are expected to become commercially available beginning within two years for a wide array of applications, including radio communications, security and automotive safety.

    In 2006, the Duke researchers made headlines by demonstrating that an “invisibility cloak” could be created by bending the light that strikes a metamaterial.

    The researchers, at the Center for Metamaterials and Integrated Plasmonics, reported Thursday in the journal Science that their scanning sensor captures both still and video images while simplifying compression by integrating it directly into the sensor array.

    A cost advantage of the new technology is that it permits image compression to be performed directly by the sensor hardware, rather than by the specialized hardware and software in use today.

    Although the cost of optical sensors has fallen rapidly, automobile manufacturers have been searching for alternatives to expensive laser radar, or Lidar, to provide sensors that work in a range of natural light conditions, including night, dust clouds and snowstorms.

    The current generation of airport millimeter-wave security scanners has gained popularity because they do not rely on X-ray radiation and its attendant health risks.

    But they require an elaborate mechanical arm that sweeps around a passenger standing in a scanning booth.

    “The drawbacks are that it takes time and adds a lot of expense because of complicated mechanical rotors,” said the lead author of the Science paper, John Hunt, a graduate researcher at the Duke center. “We have been trying to replace the whole system with one that has no moving parts.”

    Although the design of metamaterial sensors might offer high compression ratios, Mr. Hunt said the real advantage lay in the potential for reductions in size. For example, he noted, even the most advanced planes and boats today use a mechanically steered dish antenna for radar. This requires setting aside a large space to swivel the dish.

    “Our system could potentially replace that with a flat sheet wrapped onto the side of the fuselage,” he said.

    Another potential advantage is speed. Intellectual Ventures, established by the former Microsoft chief scientist Nathan Myhrvold, has started a company to develop communications antennas made from metamaterials.

    The company, Kymeta, has said it will introduce an inexpensive high-speed satellite antenna as soon as the end of next year. Bill Gates, the Microsoft co-founder, is an investor.

    Depending on the wavelength they are focused on, metamaterials are made with either printed circuit boards or semiconductors. The sensor elements can be laid out in a linear array or as a three-dimensional matrix.

    If the elements are small enough, the materials can manipulate visible light; other researchers are exploring applications with both sound waves and seismic waves.

    Metamaterials bend radiation more sharply than natural materials. One of their strangest qualities is the ability to create a structure with what scientists call a “negative refractive index” — a behavior of light and other forms of radiation that is not found when light waves pass through materials like glass or water. They can be aimed in many different directions, or used in parallel to increase bandwidth.

    http://www.nytimes.com/2013/01/18/te...l?ref=business

  • #2
    Re: Image Compression Breakthrough?

    A lot of hype. As far as I can figure, from the links to the article in Science and to Kymeta itself, the technology that's being presented:

    • Works in the K band, 18-26 GHz, millimeter-wave. This is too low even for the airport scanners, which work in the terahertz range. Visible light is way, way higher than that, in the 300 THz range (about 10,000 times higher). The higher the frequency, the smaller the structures proportionally need to be.
    • Beam steering by phase arrays has been done for quite some time. Metamaterials make that easier to do, for higher frequencies than conventional.


    To compress visible light, you would need to construct those ultra-small structures, and modify the cameras to have metamaterial sensors, then come up with the algorithms required to uncompress the signal at the other side.

    Note that the article slides deftly into talking about satellite antennas, which typically work in the K band, for which this developnment is primarily suited.

    My suspicion is that, when this technology would be ready for visible light, there will be other, better technologies for compression, or the general bandwidth availability will be so high that compression will no longer be an issue.

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    • #3
      Re: Image Compression Breakthrough?

      I guess I am a bit confused.

      Why exactly is hardware image compression a good thing?

      You can build any form of software into hardware, but you generally don't want to do so. Because if you do, changes are impossible.

      The changes can be good: improvements in performance, etc etc.

      Or they can be undoing bad: bug fixes.

      Why exactly is using metamaterials to hard wire a specific compression algorithm - which is what I believe is being touted - a positive thing? Especially since the processing power is pretty cheap these days.

      The example used is also poor: what's the link between software compression/hardware compression and the 'arm' on the airport scanners? The arm has nothing to do with the compression, but likely has everything to do with getting multiple snapshots from different angles which are then built into the final image displayed for the user/

      I think the real problem here is a poor science writer who doesn't quite understand what is being written about.

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      • #4
        Re: Image Compression Breakthrough?

        Originally posted by don View Post
        Using a new class of artificial materials, scientists at Duke University have designed a sensor that compresses images far more efficiently than existing technologies like JPEG.
        I think Destiny Media is near a release date for their compression software for mobile video. It's quite fast and used now in specialty markets but they're aiming at a release this year for devices that don't support Flash. Good product but they got their lunch eaten by Adobe the last time they went head-to-head.

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        • #5
          Re: Image Compression Breakthrough?

          I don't think hardware image compression is the main point of the technology. The title for the article was probably written by a reporter whose highest level of science was high school physics. The main application for the technology is in antennas for microwave transmitters and receivers in the K-band, in which case it provides advantages in terms of lightweight beam steering and forming that can be applied to satellites, where weight and size are critically important.

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