The Pixel 3 and Pixel 3 XL models have one of the best camera systems available on a smartphone. Still, Google makes it work with a single camera at the back of both phones. Even without a second camera on the back, the phone still produces bokeh effect in portrait mode through the use of software and other processing tips. In a blog post published today by Google, the company explains how to predict the depth of pixel 3 without using a second camera.
Last year, Pixel 2 and Pixel 2 XL used phase-detecting autofocus (PDAF), also known as two-pixel autofocus, combined with a "traditional untrained stereo algorithm" for portraits. on the second generation pixels. PDAF captures two slightly different views of the same scene and creates a parallax effect. This is used to create a depth map required to obtain the bokeh effect. And while the 2017 models take great portraits with a blurry background that can be mitigated or enhanced, Google wanted to improve the portrait mode for Pixel 3 and Pixel 3 XL.
Although the use of PDAFs works properly, there are some factors that can lead to errors in estimating depth. To improve depth estimation with Pixel 3 models, Google has added new benchmarks, including comparing fuzzy images in the background with neater close-up images. This is what is called the defocus depth marker. Counting the number of pixels in an image of a person's face makes it possible to estimate how far that person is from the camera. This is called a semantic signal. Google needed machine learning to create an algorithm allowing it to combine indices for a more accurate estimate of depth. To do this, the company had to form the neural network.
The formation of the network required numerous PDAF images and high quality depth maps. Google has created a shell that can hold five Pixel 3 phones at a time. Using Wi-Fi, the company captured the images from the five cameras at the same time (or about 2 milliseconds from each other). The five different perspectives allowed Google to create a parallax in five different directions, helping to create more accurate depth information.
Google continues to use Pixel cameras to market phones. A series of videos titled "Unchangeable" shows various owners of phones that are testing Pixel 3 to see if they will eventually switch from their current handsets. At first, most of these people say that they would never change, but that the camera and some features of Google would prevail at the end of each episode.
