All this time we’ve been saying that if Google adds face unlock to the Pixel 6 Pro, it will be a less secure 2D version. This is because without adding certain hardware features, it is not possible to create a depth map of the user’s face. And matching a flat image of a user’s face to a 2D image would allow someone to take a photo of the user’s face and use it to cheat to unlock the device with the face to unlock it.

It is a pity that there is no way to create a depth map of your face without needing all the hardware used to identify the iPhone and unlock the Pixel 4’s face. According to 9to5Google, there may be a way to get the Pixel 6 Pro (not Pixel 6) running. This also explains why rumors of a facial recognition system to appear in the Pixel Feature Drop in the future apply to the Pixel 6 Pro and not the Pixel 6.

That’s why face unlock may appear on the Pixel 6 Pro instead of the Pixel 6.

The Pixel 6 Pro uses a Sony IMX 663 image sensor and the Pixel 6 uses an IMX355. And there is a big difference between this pair, because the first supports two-pixel autofocus (DPAF), and the second – no. According to 9to5Google, starting with the Pixel 2, Google uses two-pixel autofocus to create depth maps for portrait mode with just one lens.

In a blog post written by Google in 2017, the company explains how you can create a depth map for portrait mode with a single camera. “We can use a stereo algorithm to calculate the depth. The Pixel 2 doesn’t have a dual camera, but it does have a technology called phase autofocus pixels (PDAF), sometimes called two-pixel autofocus (DPAF) in one gulp, but the idea is pretty simple.”

“If you imagine the (small) lens of the phone’s rear camera split in two, the worldview seen from the left side of the lens and the worldview seen from the right side of the lens are slightly different. These two viewpoints are less than 1mm apart (approximately the diameter of the lens), but they differ enough to calculate stereo and create a depth map. Note also that the Pixel 6 Pro has several cameras on the back.

This is just a hypothetical explanation of how Google could provide Pixel 6 Pro users with a more secure face unlock feature without having to do anything with the hardware. After all, PDAF, also known as DPAF, is used in conjunction with the Sony IMX663 sensor used in the Pixel 6 Pro!

But face unlock won’t work in low light conditions unless Google puts a projector inside the phone. However, there is a fingerprint scanner under the screen that you can use when you still can’t use face unlock. There is no guarantee that Google will add face unlock on the Pixel 6 Pro.

Note that the iPhone and Pixel 4 series only have a biometric method of unlocking these devices, so a spotlight is essential. And just because Google itself says depth maps are possible with PDAF doesn’t mean Google will use that methodology to provide some form of secure facial recognition on the Pixel 6 Pro. Source