Using your face to unlock your smartphone has been around a long time on Android, and it's used by many for its convenience over typing in a PIN or a password. With the right amount of lighting, it can even be almost as fast as fingerprint unlocking. Android's face unlock has suffered from some embarrassing mishaps, though, such as being fooled by a fake head or even just a regular 2D photo of your face. With the Pixel 4, Google is upping its game when it comes to face unlock security and speed. In addition to being secure enough now to process payments and log into apps, the Pixel 4 can recognize your face from any orientation, even upside down, and it does so very quickly.

The most impressive claim is that face unlock should work regardless of orientation. That would put it ahead of the competition where you need to be looking at the phone in a relatively straight angle to get it to unlock. Anyone who has used an iPhone while lying in bed will know that face unlock doesn't work very reliably or very quickly; the Pixel 4 should be better in that setting.

To make face unlock more secure, accurate, and flexible, the Pixel 4 comes with several sensors and cameras not found in previous Pixel phones: two face unlock IR cameras, a near-infrared (NIR) flood emitter, and a NIR dot projector. After you've finished pointing your nose at a circle of targets to train all angles of your face to the device, all face images and models are saved locally on the phone and no information is sent to Google. The built-in Titan security chip adds an additional layer of protection. With such security in place, face unlock on the Pixel 4 can now be used to make payments and quickly sign in to apps. With that said, Google includes a disclaimer stating that face unlock can still be fooled by someone that looks like you, like an identical sibling.

Sabrina Ellis, a member of the Pixel team, claimed during her stage presentation today that "Pixel 4 has the fastest secure face unlock on a smartphone." This speed supposedly comes from the Pixel 4's Neural Core and Motion Sense engines. The Pixel Neural Core is used to accelerate on-device processing, always-on listening, and machine learning. In other words, more tasks are now being done on the device for performance and privacy. Motion Sense, which uses the Soli radar chip to detect your presence and can sense you reaching out for the phone, will quickly ready the face unlock sensors for a prompt and fast scan. With these components in place, the end result is a face unlock that is safer, more secure, faster, and more flexible.

Once we've spent more time with the device, we'll let you know how it went with the upside-down face unlocking.