“A user is simply required to hold their finger on the sensor for 15 seconds, during which time the optical sensor will capture a number of images to assess volumetric changes in blood circulation.”
Xiaomi appears to have a found a novel application of Goodix’s in-display fingerprint sensor technology: on its new Xiaomi Mi 11 smartphone, the sensor can be used to measure the user’s heart rate.
The feature revolves around a technique called photoplethysmography, or PPG. A user is simply required to hold their finger on the sensor for 15 seconds, during which time the optical sensor will capture a number of images to assess volumetric changes in blood circulation.
As XDA Developers’ Brandon Russell notes, PPG is not a perfect method for assessing heart rate. Researchers have found that it can prove to be more inaccurate with certain skin types, and can also suffer from issues related to motion and signal crossover.
That having been said, it’s a novel feature for a smartphone, and could help the Xiaomi Mi 11 to stand out. It also offers a bit of extra publicity for Goodix, which has continued to raise its profile as a supplier of in-display fingerprint sensor technology over the last couple of years. The company has provided this technology for previous Xiaomi devices and has seen it integrated into a number of other smartphones from Xiaomi rivals, including new flagship devices from Vivo.
Other features of Xiaomi’s Mi 11 include the new Qualcomm Snapdragon 888 chip, a 4,600mAh Li-Ion battery, and a triple-camera imaging system. The device launched in China this month with a starting price of CNY 3,999, or about $612 USD.