Today, the computerization of society makes us look for various ways to limit 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 user biometric parameters, in particular fingerprint. And this only requires a fingerprint scanner and the corresponding software that comes with the device.
What is a fingerprint scanner
?A fingerprint scanner is a device that reads an image of a finger with all its features in the form of a papillary pattern and transfers the scan result to the software. A specialized application compares the received image with a sample created at the stage of generating a biometric password.
Types of Fingerprint Scanners
All fingerprint scanners that are currently used can be classified into three groups based on the physical principle of operation:
- semiconductor (silicon);
- optical;
- ultrasound.
Semiconductor scanners
This type of scanner receives an image based on the properties of semiconductors that change in the contact area of the papillary pattern and the scanner. The operation of this type of scanning device may be based on several technologies:
- 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.
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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.
- Radio frequency scanners. Scanners of this type consist of microantennas that generate a weak signal, and based on the magnitude of the electromotive force received in response from the papillary pattern, the final image of the fingerprint is formed.
- Lingering thermo-scanners. The same as thermal scanners. The only difference is that the finger needs to be drawn along the scanning surface, and not attached.
- Capacitive broaching scanners. The technology for acquiring an image of a papillary pattern is the same as in capacitive ones, but the method of obtaining differs in that the finger is drawn along the scanning surface.
- 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
This type of fingerprint scanner receives an image of a finger by the optical method. 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. The image is obtained from an electro-optical polymer, which in its composition has a light-emitting layer.
- Optical broaching scanners. This type of equipment is a refinement of fiber-optic devices, in which to obtain an image it is necessary to hold a finger on the surface, and not apply it.
- Roller scanners. To obtain an image, you need to drag your finger along the clip, where you take pictures of your finger with papillary patterns.
- Contactless scanners. Finger scanning is carried out in a non-contact manner. The finger is applied to the hole, where several sources highlight it, and the built-in camera captures the image of the finger.
Ultrasound scanners
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.