In 2017 Apple introduced Face ID for iPhone. The system can be used for unlocking a device, making payments, accessing sensitive data, providing detailed facial expression tracking for Animoji, as well as six degrees of freedom (6DOF) head-tracking, eye-tracking, and other features. Eight years later and Google has filed a patent for a similar feature (copycat) for possible future Pixel smartphones.

In general, Google’s patent application covers techniques for a smartphone to generate patterns of dots that are used to perform depth mapping of a scene without use of a separate diffractive optical element that diffracts light into one or more patters of light dots. Instead, the display of the computing device may act as a diffractive optical element that diffracts light into patterns of dots that can be used to perform depth mapping of a three-dimensional scene.

The computing device may include a light source that may emit light towards the display of the computing device. The display may include a periodic structure that forms a two-dimensional arrangement of opaque regions and transparent regions. The arrangement of opaque regions and transparent regions of the periodic structure may cause the light to constructively and destructively interfere with each other, thereby diffracting the light into one or more specific patterns of light dots that are projected onto a three-dimensional scene.

 A camera of the computing device may capture the pattern of light dots in the three-dimensional scene and may determine depth values associated with the pattern of light dots to generate a depth map of the three-dimensional scene.

In some aspects, the techniques described in Google's patent relate to a computing device including: a display having a periodic structure; a light source configured to emit light towards at least a portion of the display, the periodic structure of the display diffracting the light into a plurality of light dots that are projected onto a scene; a camera configured to capture the plurality of light dots in the scene; and one or more processors configured to determine depth values associated with the plurality of light dots.

The Pixel's Face Unlock feature debuted in 2019. Google's latest patent was only filed in 2023 (published in the last 30 days). So it's a different technology approach emphasizing the dot projector methodology that the iPhone uses.