Fri Feb 24 14:14:19 CST 2023
In the past, unlocking a phone required entering a password. Then the password was overtaken by the fingerprint sensor embedded in the smartphone. Then in 2017, Apple introduced Face ID to improve security for the broader smartphone industry. face ID is so convenient to unlock that it requires no movement, lifting your hand to unlock in seconds, and the whole process is very natural. What's more, Face unlock is more secure than fingerprint unlock!
Face ID is Apple's modern biometric authentication system. It uses a face scan instead of a fingerprint to unlock your phone. It has an additional sensor, called the TrueDepth camera, located next to the front-facing camera on iPhone. Instead of an image, this TrueDepth camera measures depth. That's what makes Face ID so secure. Face ID is scanning for depth as it looks at your face.
The advantage of biometric authentication systems over traditional authentication systems such as passwords or keys is that you don't have to remember any passwords or carry a physical key with you.
Touch ID has a false alarm rate of 1 in 50,000. Face ID has a false alarm rate of 1 in a million. That means Face ID is 20 times more secure than Touch ID.
Why is it more secure? Simply because Face ID's sensors read many more data points than Touch ID's sensors. That's thanks to the TrueDepth camera system it uses.
The truth is, Face ID doesn't know exactly what you look like. It only knows what shape your face is. If someone tries to unlock your iPhone using a photo of you, Face ID will know it's not you because the photo has no depth.
When deciding whether to unlock it for you, Face ID counts more than 30,000 points of interest on your face, measuring tiny differences in the depth of your nose, mouth, eyelids, and so on. If those differences don't match exactly, Face ID knows it's not really you trying to unlock your iPhone.
Face ID uses what Apple calls "TrueDepth Camera" to capture your face.
This TrueDepth camera is not the front-facing camera that you use to take pictures on your phone, but a different camera. It's a combination of the iPhone's light and infrared projectors and sensors. All of these take images of your face and provide data.
Using all these data, the TrueDepth camera reads 2D infrared images and more than 30,000 infrared points to form a depth map of your face. Your iPhone then combines all these images and their data to build a detailed 3-D map of your face. That's why you rotate your head in a circle - so your iPhone can capture the unique contours of your face!
Your facial map includes data that we can see (visible to the naked eye) and data that we can't see (invisible to the naked eye). Combining this data allows Face ID to work in a variety of lighting conditions, including low-light conditions like nighttime.
By using the front Infrared Camera and Dot Projector component (shown above) to actively emit specific infrared structured light to illuminate the object being detected, the iPhone is able to quickly scan a person's face and form 30,000 invisible IR dots on the surface of the face, just like 3D modeling.
By acquiring PrimeSense, the iPhone X has a virtual monopoly on this method of using structured light on phones.
To better analyze the data collected, Apple also built its own neural network specifically based on the capabilities of the A-series chip, providing enough computing power for face recognition to make the process of facial entry and unlocking smooth and fast.
By HornmicLink_Henry @230224 14:22