The magic behind Apple’s Face ID
Can an iPhones Face ID work in the dark?
With the launch of the iPhone X, Apple once again revolutionized the Smartphone Industry. The iPhone X contains significant changes such as super-thin bezels, a larger display, major camera up-gradation, and the notch. Apple has a habit of removing a key feature; continuing their legacy with the iPhone X; they replaced our beloved Touch ID with the new Face ID. Concerns were raised regarding the accuracy, usability, privacy, as the first thought to our mind is that our face will be stored somewhere in the system to recognize us, and another thing that has triggered the curiosity of people is:
Can an iPhones Face ID work in the dark?
The common myth is that you cannot unlock your iPhone with your face in the dark. Well, that is wrong. To know how this is done, let us go down the rabbit hole and see how the Face ID works; the process behind it is pretty interesting.
How does the iPhone scan your face? What components are being used to do so?
At first, you may think that it just uses the camera and some software for processing, but if this was the case, people would be able to unlock their iPhones with just their photos leading to catastrophes and tons of lawsuits against Apple; but this is not the case.
The process of scanning our face happens inside the notch. It includes a time-of-flight camera, flood illuminator, IR camera, and a dot projector. Imagine 30,000 lasers coming out from a small point on your face. Exactly what iPhones do; Face ID uses a feature called ‘Laser Projection’ to do so. The Flood illuminator with the Dot projector can scan our faces from any angle; it projects 30,000 lasers on your faces and maps your facial features in 3D.
The 3D mapping data is encrypted and stored on Apple servers with the users’ passcode as the second factor for authentication to unlock their phone using Face ID.
After Apple stores, the 3D mapping data — Apple claims that they delete photos from your phone and its servers after approximately one minute and is inaccessible to anyone but you.
What happens after projecting 30,000 lasers?
Remember the time-of-flight camera inside the `notch`? Here comes the use of it. So, after projecting 30,000 dots on your face, the time-of-flight camera with the IR camera detects 30,000 infrared dots to create a 3-D map of your face in milliseconds.
All this captured data gets processed inside the iPhone X customized neural engine, built into its image signal processor, designed to enable real-time information processing at a rate of 600 billion operations per second.
After the data is processed, the iPhone can create a precise depth map of your face and analyze over 100 distinct facial features for accurate identification.
This technology used in Face ID is pretty different from the other systems used in other smartphone makers; to make facial recognition work on other smartphones, their makers activated the front-facing camera and used the 2D image of users face for identification. However, this method has limitations because it cannot tell whether a person is looking at the screen or not, along with the issue of unlocking the phone with pictures.
What technology is used in Apple Face ID, which projects 30,000 lasers?
Apple Face ID uses LIDAR, and it is one of the most popular optical remote sensing technologies.
Lidar uses the Flood Illuminator along with IR infrared camera to send out signals to be reflected back from the lidar target. LIDAR also has two different types of laser beams: one to illuminate the target and one beam that returns an image to the camera.
Apple has been investing in lidar technology since 2013 when they bought PrimeSense, an Israeli company that specializes in 3D imaging. Then, in 2016 Apple announced a $390 million deal with a German company called Osram to produce laser diodes necessary to make lidar a mass-producible technology.
LIDAR is the technology behind the projection of 30,000 laser dots that the iPhone X uses to scan your face terrain or contour, creating a precise depth map of your face. It then uses this map to compare it to models in its system to detect if it is you or not. All of it is done in infrared, so it also works in the dark.
There are tons of applications of LIDAR. It can be used to create a map of our surroundings in the dark to navigate in stealth or create 3D models of objects around you.
A recent study published by Italian researchers from CNR Institute for Scientific Communications shows that for a second person to unlock the iPhone X, he will have to block 30% more laser beams than standard facial scanning. It means that the accuracy of Face ID technology is lower than expected.
Do the Face ID lasers hurt human eyes?
Well, all these laser projections and dots raises safety concern for our eyes; the straightforward answer is No, as it emits very-low infrared light (less than 2% of the LED Eye Safety Standard Regulation).
It is not dangerous for humans to stare at LIDAR if they don’t go too close to the camera. The distance of 30 cm between the camera and the human is pretty safe.
Researchers found that human eyes can be affected by staring at lidar, but the injury varies depending on location and other factors.
Previously, iPhone could be unlocked; if the TRUE Depth sensors are sure that you are seeing towards the phone, but now it works even if your eyes are closed.
