How Fingerprint Scanners Work

Fingerprint recognition attendance is a typical pattern recognition system, including modules such as fingerprint image acquisition, processing, feature extraction and comparison. Fingerprint image acquisition: live fingerprint images can be collected through a special fingerprint collector. At present, fingerprint collectors mainly include living optical, capacitive and pressure sensitive. For technical indicators such as resolution and acquisition area, the public security industry has formed international and domestic standards, but there is still a lack of unified standards for others. According to the area of collected fingerprints, it can be roughly divided into rolling fingerprints and flat fingerprints. The public security industry generally uses rolling fingerprints. In addition, the fingerprint image can also be acquired through a scanner, a digital camera, and the like. Fingerprint image compression: Large-capacity fingerprint databases must be stored after compression to reduce storage space. The main methods include JPEG, WSQ, EZW, etc. Fingerprint image processing: including fingerprint area detection, image quality judgment, direction map and frequency estimation, image enhancement, fingerprint image binarization and refinement, etc.

The first generation of fingerprint recognition and attendance The first generation of fingerprint recognition and attendance The first generation of fingerprint recognition and attendance The first generation of fingerprint recognition and attendance is well known. Two years ago, some brands of notebooks used fingerprint scanners for identity verification when users log in. The first However, the fingerprint system introduced at that time belonged to the optical identification system. According to the current statement, it should belong to the first generation of fingerprint scanners. Optical Fingerprint Recognition Time Attendance can only scan the surface of the finger skin, or scan the dead skin layer, but cannot go deep into the dermis because light cannot penetrate the surface layer of the skin (dead skin layer). In this case, the cleanliness of the finger surface directly affects the recognition effect. If there is a lot of dust on the user's fingers, recognition errors may occur. Moreover, if people make a fingerprint hand model according to their fingers, they may also pass the identification system. For users, it is not very safe and stable to use. The second generation of capacitive sensors, the second generation of capacitive sensors, the second generation of capacitive sensors, the second generation of capacitive sensors, and the second generation of capacitive sensors, the capacitive sensor technology uses the parallel arrangement of alternating commands and the sensor board, alternating plate
Second-generation capacitive sensors take the form of two capacitive plates, and the valleys and ridges of the fingerprint become the dielectric between the plates. The sensor detects changes in the constant dielectric between the two to generate a fingerprint image. However, since the surface of the sensor is made of silicon material, it is easy to damage, resulting in reduced service life, and it forms a fingerprint image through the valleys and ridges of the fingerprint, so the recognition rate for dirty fingers, wet fingers, etc. is low.
The third-generation bio-RF Fingerprint Scanner is now invented. The RF sensor technology emits a small amount of RF signals through the sensor itself, penetrating the skin layer of the finger to control the texture of the inner layer to obtain the best fingerprint image. Therefore, for dry fingers, Han`s third-generation biological radio frequency sensor fingers, dry fingers and other difficult fingers can pass through up to 99@%, and the anti-counterfeiting fingerprint ability is strong. To solve the problem of artificial fingerprints, wide temperature range: suitable for extremely cold or extremely hot areas. Because RF sensors produce high-quality images, RF technology is the most reliable and robust solution. In addition to this, the high image quality allows the sensor to be reduced without sacrificing the reliability of the authentication, thereby reducing the cost and enabling the application of the RF sensor idea to any field where the mobility and size are not constrained.