Fingerprint recognition: At present, there are two main types of fingerprint recognition technologies for smart locks on the market, optical fingerprint recognition and semiconductor fingerprint recognition.
Optical fingerprint recognition is to use the refraction and reflection of light to collect the optical image of the fingerprint of the finger through the optical sensor, and then compare and identify. Optical fingerprint recognition technology is widely used, and most of the punch card machines or access control for daily commuting and get off work use this technology. The cost of optical fingerprint recognition is low, but there is a risk of being stolen by fake fingerprints (such as silicone simulated fingerprints) in terms of security.
Semiconductor fingerprint recognition: It mainly uses the principles of capacitance, electric field, temperature, pressure, etc. to realize the collection of fingerprint images. The semiconductor fingerprint recognition module only recognizes living fingerprints, can penetrate the skin surface layer, and has high security. Can prevent simulated fingerprint cracking.
Finger/palm vein identification: The hemoglobin in the blood flowing in the finger vein absorbs infrared light to form a vein image, which is detected and verified. This identification method collects deeper biological information, which is difficult to steal and difficult to copy. It must be identified only by flowing blood, and the security is higher. And the elderly, children, and special groups can be identified, stable, and the recognition rate is high.
3D face recognition: use a 3D camera to build a 3D face model of the user, detect and track the features of the face through live detection and face recognition algorithms, compare and verify with the 3D face information stored in the door lock, and unlock the door. There are currently three mainstream solutions for 3D vision: structured light, binocular vision, and light time-of-flight method.
3D structured light is the mainstream technology in current smart locks. This solution uses professional projection module triangulation to form a more dense and reliable three-dimensional face that is difficult to replicate. The most widely used application of 3D structured light is face unlocking and payment. In addition to smart door locks, it is also widely used in mobile phones and payment industries, which can reach payment-level security standards. However, according to the author's experience, the current speed of face recognition is not perfect.
NFC unlocking: Smart locks with NFC function can read the information of mobile phones, watches and bracelets with built-in NFC, and realize unlocking with mobile phones, watches and bracelets.
Voice unlocking: This is mainly through Apple HomeKit, using Siri for voice control to unlock the door. For example, when doing housework at home, or in other situations where it is not convenient to open the door, shout "Hey Siri, open the door lock" to the iPhone, and the door will automatically open, making life more convenient.