As biometric authentication software becomes smarter and sensors for facial recognition get smaller, the day when smartphones of all kinds can reliably and securely be unlocked just by recognizing the user's face is expected to come soon, a big step up from simple fingerprint scanners and password requirements.
On the smartphone battleground, tech companies like Xiaomi, Apple and Samsung are already competing to make this breakthrough a reality as soon as possible.
This week alone saw three new smartphones with facial recognition unlocking features line up for consumers.
On Monday, Xiaomi's founder Lei Jun unveiled a 5.5-inch display dual-camera flagship titled Mi Note 3, claiming that a user can get access to their smartphone with just a glance.
A day later, Apple Inc's long-awaited 10th-anniversary iPhone X, with a 5.8-inch edge-to-edge OLED display, came with a front-facing 3D laser scanner for facial recognition purposes, branded as "Face ID".
And Samsung's latest Galaxy Note 8 officially hit the Chinese market on Wednesday, also featuring facial recognition.
Earlier this month, China's rising star phone maker Vivo showcased a new phone model V7+ that can be unlocked via face scanning at a conference in India and plans to roll out X20, believed to be a variant of V7+, in its home market on September 21.
Prior to the emergence of face unlock features, fingerprint sensors, as in Apple's Touch ID feature and other similar technologies, have already turned smartphones into miracles of convenience. Just the touch of a finger can unlock phones and make digital payments, with no passwords required. But this feature is far from perfect and can fail depending on how wet or dry the user's finger is.
Face unlock, however, does not have those issues. Compared with the widely used fingerprint scanner, "the facial recognition sensor is a hands-free, biometric authentication technology that will be handier for phone users," Yang Fan, vice president and co-founder of Chinese artificial intelligence unicorn SenseTime Group Ltd, told the Global Times Tuesday.
In terms of speed, Lei claimed that the face unlock feature of Mi Note 3 is as fast as a fingerprint scan, taking half a second, while Vivo promoted that its X20 can be unlocked by recognizing your face in one-tenth of a second only.
Face unlock adoption of smartphones can become a trend, Wu Wenhao, vice president at Beijing-based AI start-up Megvii Technology Inc, also known as Face++, told a press conference on Tuesday.
Data from Taipei-headquartered market intelligence agency TrendForce can reflect Wu's projection. The agency estimated earlier this year that the global market scale of infrared sensory modules used for iris and 3D facial recognition solutions for mobile devices will grow from $145 million in 2017 to $827 million by 2025, at a compound annual growth rate of 24 percent during the forecast period.
More than unlocking
Apart from unlocking devices, 3D facial recognition can also serve other purposes such as augmented reality (AR) experiences, Xiang Yang, an industry expert at Beijing-based CCID Consulting, told the Global Times.
Powered by Apple's ARKit software, iPhone X has been used to showcase some AR functions such as allowing users to superimpose virtual games, images and videos onto objects in the real world.
The phone's 3D face-tracking ability in its selfie camera can also create "AR selfies". This is expected to bring the tech aspect of social media to a whole new level, as social networking apps like Snapchat and Instagram are already experimenting with AR pictures and videos.
No AR features have been found in the smartphones of other brands yet however. Xiang said that for low-budget phone makers like Xiaomi and Vivo, it is unnecessary to add costly AR experiences. "Facial recognition unlocking is already a good selling point for them," he noted.
Mi Note 3 was priced up to 2,999 yuan ($459.6). By contrast, iPhone X will cost more than $999.
The 3D laser scanner adopted by iPhone X is said to add $10 to $15 per module to the phone's component bills, according to MacRumors quoting analyst Rod Hall of JPMorgan.
As for Samsung, the company was quoted by New York-based news portal Business Insider in March as saying that it mainly treats facial recognition as a convenient way of going to the Home screen supplementary to its iconic Slide to Unlock feature.
Despite having those above-mentioned merits, face unlock does not seem to add much attractiveness to smartphones in the view of consumes like Qin Hao, a 31-year-old Beijing resident.
"This is not a must-have feature. The old-fashioned password is enough for my daily use," Qin told the Global Times on Tuesday.
The man has not activated Touch ID on his iPhone 6 Plus yet over security concerns.
Full human fingerprints are unique and may be difficult to forge, but the fingerprint sensor on phones is so small that they can read only a part of my print, he said. "How can it be reliable?"
Qin said he also questioned the security of the new biometric authentication, referring to recent media reports that the 2D facial recognition on Samsung's smartphones can be easily duped with a photo.
Apple, Xiaomi and Vivo all outsmarted Samsung's 2D features by applying 3D sensors.
With 3D sensors, facial recognition technology is less likely to be tricked by photos and digitally composed video sequences, said Yang. Based on SenseTime's experiences, current facial recognition technology holds a two in 1,000 chance of being fooled and it can defend over 95 percent of malicious unlock attempts.
Apple, which has acquired gains of intellectual patents related to 3D sensing via its acquisition of PrimeSense signed in 2013, appears to be expressing more faith in its facial recognition technology.
For its latest phone series, the company surprisingly replaced the iPhone's iconic Touch ID with Face ID and removed the Home button to allow a full-screen display, while other players are still sticking with fingerprint features and passwords in addition to face unlocking.
Samsung Galaxy S8, a flagship smartphone launched in late March, even reportedly recommends users that intend to try out facial recognition to consider iris or fingerprint scanners instead, citing that the phone can be tricked by photographs.
Apple claimed that there is a "one in a million" chance that iPhone X can be unlocked by someone else's face. Face ID will also be used for Apple Pay transactions.
The face unlock features on Xiaomi's Mi Note 3 and Vivo's X20 were both supported by Face++, which did not reveal the chances of being fooled to the public. However, Wu noted at the Tuesday conference that the technologies used for phones are not as advanced and secure as those applied to security systems used by financial institutions yet.
Although Apple's iPhone X sounds exciting, Qin, the consumer, did not intend to buy it given the high price tag and longer-than-expected launch. Usually, new iPhones go on sale at the end of September, but the super-premium new phone will not ship until November.