After showing off the back of the Pixel 4 in June, Google is again taking the unprecedented step of publicly detailing an unreleased smartphone. The newest post on the company blog is all about the Pixel 4's big top bezel and the tech goodies contained within.

First, Google confirms the earlier rumors from 9to5Google that the device will integrate Project Soli technology:

Pixel 4 will be the first device with Soli, powering our new Motion Sense features to allow you to skip songs, snooze alarms, and silence phone calls, just by waving your hand. These capabilities are just the start, and just as Pixels get better over time, Motion Sense will evolve as well. Motion Sense will be available in select Pixel countries.

Soli, or "Motion Sense" as it's being called in the Pixel 4, is powered by radar. Google's Advanced Technology and Projects team (ATAP) has been working on shrinking down radar into a tiny chip for the last five years. As originally pitched, Soli was capable of detecting a number of fine hand gestures, like tapping your thumb and index finger together for a virtual button press or rubbing the two fingers together to scroll or turn a virtual dial. Google's old Soli YouTube video claims the technology is capable of tracking "sub-millimeter motions at high speed and accuracy," but in this first consumer device, the video shows waving your hand across the entire face of the phone to skip music. Gestures like this have been done before on Samsung and Motorola phones with cameras and other optical sensors, and they were not well received enough to be carried forward to future devices.

Google notes that "Motion Sense will be available in select Pixel countries," which probably indicates that Soli will have some regulatory hurdles to overcome. Soli operates in the 57- to 64-GHz frequency band, and in the US, Google had to get the FCC to lift power limitations in those bands so Soli could work better. If an international regulatory body is not as accommodating as the FCC, it sounds like the Pixel 4's Soli capabilities will be shut off in that country.

Google provided a diagram of all the stuff that lives in the top bezel of the Pixel 4, and there are quite a few surprises. First the "second front camera" spot that we've seen on renders isn't set up like the Pixel 3, with a wide-angle lens. The wide-angle lens is being cut for a "face unlock IR camera." There are actually two face unlock cameras besides the main selfie cam. Along with a dot projector and flood illuminator, it looks like the Pixel 4 is getting a full-blown copy of Apple's FaceID. Google says it's making some improvements over Apple's implementation, though, with faster activation:

Other phones require you to lift the device all the way up, pose in a certain way, wait for it to unlock, and then swipe to get to the homescreen. Pixel 4 does all of that in a much more streamlined way. As you reach for Pixel 4, Soli proactively turns on the face unlock sensors, recognizing that you may want to unlock your phone. If the face unlock sensors and algorithms recognize you, the phone will open as you pick it up, all in one motion.

Google promises that its FaceID "image data never leaves your phone" and that the data is "never saved or shared with other Google services." Soli data will get the same on-device treatment.

The Pixel 4 should be out sometime before the end of the year. We're sure we'll see more leaks (and maybe even more posts from Google) before then.

Listing image by Google