If I had to choose between Touch ID and Face ID, I would go to Apple's 3D Face Detection System without thinking twice. It turns out I did not miss Touch ID at all and it was one of my first concerns last year when Apple revealed that iPhone X would not have fingerprint sensor properties.
I've used Face ID for more than a year now, with hardly any problems, and I still rock an iPhone X. But it turns out that Apple has not completely given up the idea of combining Touch ID and Face ID on iPhone .
Long before iPhone X arrived, some rumors claimed that the handset would contain a fingerprint sensor and Face ID on the display, but that was not the case. Apple chose Face ID over Touch ID, explaining that face recognition technology is far more sophisticated and safe than fingerprint scanning. Many rivals copied the iPhone X notch without copying Face ID functionality, and only a few companies tried to do it, including Xiaomi and Huawei. And only a few Android phones have both 3D face detection and an in-display sensor ̵
This gives us the illustration below, which comes from an Apple biometric patent like Patently Apple discovered in Europe. Apple applied for the patent in January 2018, several months after the iPhone X was introduced.
The European Patent Office released two Apple biometric patents, including details about technology that will allow users to switch between Face ID and Touch ID authentication on the same iPhone.
The image above shows a user interface on an iPhone design that takes place iPhone X that will instruct the user to use Touch ID if Face ID authentication failed and allow them to repeat Face ID scan. Similar images show a user interface that allows the user to use a password instead of Face ID.
The feature seems to indicate that Apple has at least considered using both Face ID and Touch ID on the same devices, be it an iPhone, iPad, or anything else. But just because Apple explored these mechanisms does not mean we'll see them at all anytime soon. There are currently no rumors that float around that will support the idea that Apple makes an iPhone that will contain both Face ID cameras and a fingerprint sensor. As always with patents, companies look to cover all their reasons when it comes to new inventions.
This special technology that allows the user to repeat Face ID scan or use a password is already in place on the iPhone. If your iPhone is having trouble recognizing your face, it will prompt you to enter your password. Unless you have just restarted the phone, you should not enter the password. Instead, try another Face ID scan, which will force the algorithm to scan your face and retrain itself, hopefully better for next time.