Various methods are utilized to support liveness detection, including the following:
Motion analysis
The system may assess the movements of the subject to determine if it’s a live person. It’s looking for natural motions and behavior patterns akin to what a live human would produce.
If there is a fraudster trying to use an image of a person to pass biometric authentication, the system should detect the lack of subtle movements like blinking or facial expressions that would indicate there’s an actual person present.
3D depth sensing
Another important method for liveness detection is 3D depth sensing, which uses laser scanners and other technology to map out a person’s scanned facial features in three dimensions.
This can help differentiate between a live person completing a facial scan or a photo or video of a person’s face, which is only two-dimensional.
Challenge and response tests
In active liveness detection, the system may prompt certain challenges for the user to complete, expecting a certain type of response from a live person.
By instructing the user to engage in specific tasks, like nodding their head, repeating a certain phrase, or blinking their eyes, the system can analyze their response and determine whether or not it’s in line with how a real human would behave.
For instance, if someone is trying to use a photo of a person’s face to bypass a facial recognition test, they should not be permitted access if challenged to blink, which they would be unable to do properly with just an image.
Texture analysis
Liveness detection systems can also use texture analysis to take a closer look at the provided biometric features.
This is done to detect signs of life that are typically not captured accurately in a photo or video, including fine lines, wrinkles, pore shape, skin texture, and other imperfections associated with a living human.