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Samsung's Newest Phones Read Your Fingerprints With Ultrasonic Sound Waves (cnet.com)

An anonymous reader quotes CNET: The Galaxy S10's in-screen fingerprint scanner may look just like the one on the OnePlus 6T, but don't be fooled. Samsung's flagship Galaxy S10 and S10 Plus are the first phones to use Qualcomm's ultrasonic in-screen fingerprint technology, which uses sound waves to read your print.

Related to ultrasound in a doctor's office, this "3D Sonic Sensor" technology works by bouncing sound waves off your skin. It'll capture your details through water, lotion and grease, at night or in bright daylight. Qualcomm also claims it's faster and much more secure than the optical fingerprint sensor you've seen in other phones before this. That's because the ultrasonic reader takes a 3D capture of all the ridges and valleys that make up your skin, compared to a 2D image -- basically a photo -- that an optical reader captures using light, not sound waves.

2 of 26 comments (clear)

  1. How does it work? by goombah99 · · Score: 2

    Anyone know how it gets the resolution it needs? Even ultrasonics have long wavelengths. It would have to be extremely high frequency to image the finger. But perhaps they use some sort of channeled time domain reflectometry or near field methods to get the lateral resolution.
    Still it's not obvious what they mean from the description

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    1. Re:How does it work? by LynnwoodRooster · · Score: 2

      Interferometry. A 1 MHz wavelength is human tissue is about 1.5mm. A decent interferometric system can discriminate down to 3 degrees without an issue, which would be around 12.5 microns. Which is about half the height of a fingerprint ridge. So it seems pretty simple, since you can get presence/absence of a pattern over an area.

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