How fingerprint sensor works?

There are plenty of sensors present in our smartphone and fingerprint sensor is one of the most prominent sensor in them.

The password formed by the combination of letter and word can be guessed with the knowledge of computer programming or by hit and trial method. So there was a need of much stronger security, hence fingerprint sensor came into the picture.

There are three different kind of pattern namely Arch, Loop and Whorl which make each fingerprint unique. Fingerprint sensor analyze them for better security and block unauthorized access. Optical fingerprint sensor and Capacitive fingerprint sensor are two major classification of fingerprint sensor.

As one taps his finger from different angle while registering fingerprint for the hardware, Optical fingerprint sensor take snap of finger from different angle and prepare a map removing a common area. This map is stored in the memory and whenever a user tries to open the device with his fingerprint, optical fingerprint sensor makes sure that it is matched with the previous map present in memory. On matching it grant access to use otherwise denied. Map is prepared by taking care of key information of finger like ridges bifurcation, smaller ridges and ridges end. It also takes valley i.e. the gap between two ridges in account to prepare map.

Another kind of fingerprint sensor, i.e. capacitive fingerprint sensor makes use of capacitor of very small size which is placed on the fingerprint sensor. When a user presses his finger on the sensor while registering, ridges area gets activated and capacitor present in the valley region didn’t get activated, and thereafter it prepares a map for the same which is recalled and matched when a user tries to unlock hardware with his fingerprint.

As optical fingerprint sensor takes snap of finger from different angles, so it can be fooled by presenting a copy of fingerprint in front of it, whereas capacitance fingerprint sensor makes use of capacitor and work on ON-OFF concepts so it can’t be fooled easily.

Acceptance rate i.e. how quickly and accurately it identifies fingerprint. Normally the acceptance rate is 90% which make sure that no unauthorized person accesses the account.