Today, the computerization of society makes us look for various ways to restrict access to information stored on a computer. Moreover , the user authorization and authentication system with a password is one of the most common, although it has many disadvantages. An alternative to password protection can be authentication based on the user's biometric parameters, in particular by fingerprint. And this only requires a fingerprint scanner and the corresponding software that comes with the device.
What is a fingerprint scanner ?, . , .
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- Capacitive scanners. The operation of such scanners is based on the effect when the pn junction capacitance in a semiconductor device changes when the ridges of the papillary pattern and the elements of the semiconductor matrix come into contact.
- Pressure sensitive scanners. A fingerprint scanner of this type in its work uses a special matrix of piezoelectric elements. When the finger is in contact with the matrix, the ridges exert pressure on it, but there are no depressions, respectively. Based on the pressure exerted on the matrix, an image is formed.
- Thermo-scanners. Scanning devices of this type use sensors consisting of pyroelectric elements. These sensors record the temperature difference, and then convert it to voltage.- . , , - .
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- Radio-frequency broaching scanners. The principle of operation of these devices is the same as in radio-frequency devices, but the method of taking an image is not to apply a finger to the device, but to draw a finger along its surface.
Optical scanners
A fingerprint scanner of this type receives an optical image of a finger. The basis of the operation of devices of this type are various technologies- FTIR scanners. These devices use the effect of distorted internal reflection.
- Fiber optic scanners. The fingerprint scanner is an optical fiber matrix, each fiber of which contains a photocell.
- Electro - optical scanners. Image acquisition comes from an electro-optical polymer, which in its composition has a light-emitting layer.
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This type of device scans the surface of a finger with ultrasonic waves, and an image is built based on the measured distance of the reflected waves from the depressions and protrusions. This type of device differs from the above considered in that the scan result is better.