Too bad there isn’t a way to generate a depth map of your face without requiring all of that hardware used on the iPhone’s Face ID and the Pixel 4 series’ Face unlock. Well, according to 9to5Google, there might be a way for the Pixel 6 Pro (and not the Pixel 6) to make this work. It also explains why rumors of a facial recognition system coming in a future Pixel Feature Drop usually involve the Pixel 6 Pro and not the Pixel 6. This is why Face unlock might come to Pixel 6 Pro and not the Pixel 6.
We’ve been saying all along that if Google adds Face unlock to the Pixel 6 Pro, it’ll be the less secure 2D version. That’s because building a depth map of a user’s face would be impossible without specific hardware attributes. And by matching a flat image of a user’s face with a 2D image, someone might snap a photo of a user’s face and fool Face unlock into opening a device.
The Pixel 6 Pro uses the Sony IMX 663 imaging sensor vs the Pixel 6’s IMX355. And there is a big difference between the pair as the former supports dual-pixel auto-focus (DPAF) while the latter doesn’t. As 9to5Google notes, ever since the Pixel 2, Google has used dual-pixel auto-focus to create depth maps for Portrait Mode with just one lens. In a blog post written by Google back in 2017, the company explains how a depth map for Portrait Mode can be created with just one camera. “To compute depth we can use a stereo algorithm. The Pixel 2 doesn’t have dual cameras, but it does have a technology called Phase-Detect Auto-Focus (PDAF) pixels, sometimes called dual-pixel autofocus (DPAF). That’s a mouthful, but the idea is pretty simple.”
However, unless Google placed a flood illuminator somewhere inside the phone, Face unlock would not work in low-light conditions. But there still is the under-display fingerprint scanner that could be employed when Face unlock can’t be used.There is no guarantee that Google will add Face unlock to the Pixel 6 Pro
“If one imagines splitting the (tiny) lens of the phone’s rear-facing camera into two halves, the view of the world as seen through the left side of the lens and the view through the right side are slightly different. These two viewpoints are less than 1mm apart (roughly the diameter of the lens), but they’re different enough to compute stereo and produce a depth map.” And don’t forget that the Pixel 6 Pro sports multiple cameras on the back This is just a hypothetical explaining how Google might be able to give Pixel 6 Pro users a more secure Face unlock without having to do anything to the hardware. After all PDAF aka DPAF is used with Sony’s IMX663 sensor employed on the Pixel 6 Pro!
Remember, the iPhone and the Pixel 4 line have only one biometric method for unlocking those devices and thus the flood illuminator is/was a necessity. And just because Google itself says that depth maps are possible using PDAF doesn’t mean that Google will use this methodology to deliver some sort of secure facial recognition to the Pixel 6 Pro.
It all goes back to the iconic words of fictitious mathematician Ian Malcolm played by Jeff Goldblum in the Jurassic Park series when he said, “Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should.” After all, the impact to the already beleaguered battery could be large. Last month, a Twitter tipster said that Google was testing what the impact to the Pixel 6 Pro’s 5003mAh battery would be if it was added to the device via a Quarterly Feature Drop.