With the development of technology, fingerprint identification technology is also constantly improving, from the initial optical recognition technology to the photoelectric recognition and AI recognition and other technical means, fingerprint identification technology is constantly developing and progressing.
The fingerprint recognition device is also one of the more popular products at present, and the fingerprint recognition device is divided into laser type fingerprint recognition device and capacitive fingerprint recognition device.
Laser type fingerprint scanner is through the use of laser principle for fingerprint identification, compared to capacitive type, its advantages are: small size, light weight, low power consumption, etc..
The capacitive fingerprint scanner, on the other hand, can directly place the finger on top of the sensor for recognition, mainly by sensing the change of capacitance on the finger and thus for recognition.
We can understand these two products from the following aspects.
Generally speaking, in the same finger shape, the smaller the finger the higher the capacitance value. For example: a finger width of 4 mm, then it corresponds to a capacitance value of 10 pF at 3 mm (pF is the effective value).
The capacitance sensitivity of the two fingerprint recognition devices is not the same.
The capacitance value is also different when there is a different area of indentation on the finger.
Of course, there are other factors besides the finger shape that can affect the capacitance value.
For example, if there is an uneven area on the finger, this will lead to some capacitance changes within a certain range, which will cause the capacitance to become larger or smaller; if there is a depression, the sensitivity of the fingerprint reader will be reduced.
Fingerprint identification system is a multi-step process, including the collection, encryption, comparison and other processes, in order to ensure security, we need to choose a good fingerprint identification device and fingerprint collector.
1、Conduct a series of complex processing on the collected fingerprint image to get a high quality unlock image.
2、The algorithm comparison is used to determine whether the fingerprints are exactly the same as those already recorded in the database during verification, and the user is graded according to the matching degree: Grade A (extremely high), Grade B (low) and Grade C (low).
3、Real-time fingerprint matching test with special hardware equipment.
4、When the user's fingerprint is identified, the fingers in the database that have not been recorded with finger identity information will be verified one by one.
5、Fingers that pass the verification and do not contradict the recorded fingerprint identity information will be unlocked at last.
Three, use cost
The capacitive fingerprint reader does not need to be charged because there is no electricity inside it (usually built-in lithium battery), so the use cost is low.
The laser fingerprint reader uses laser emission, which will not cause any damage to the finger and has high reliability. And it has an internal chip to record fingerprint information, so it does not need extra storage space and power supply equipment.
The capacitive fingerprint reader, on the other hand, has no electricity inside it because it collects information (including fingerprints) through capacitance.
The general capacitive fingerprint reader has lower usage cost and usage time than the laser type.
In summary, we can find that both have their advantages and disadvantages. Although most of the smartphones on the market now use capacitive fingerprint recognition technology, there is not enough market share because of its shortcomings in security, reliability and stability.
Fourth, the scope of application
Laser type fingerprint identification device.
It can be widely used in finance, public security, government agencies (immigration management system), and hotels, guest houses and other places.
Widely used in electronic payment, smart watches and access control attendance system and other fields.
Applicable places are mainly: smart phones, watches, wallets and so on. In addition, it can also be used in the financial field of account opening and authentication, etc.
With the development of science and technology, the future fingerprint identification technology will be more advanced, which is also the current market demand point decided by.
Fifth. Identification principle
(1) capacitance: there are generally two methods.
(2) frequency: that is, the capacitance size of the finger, generally has 10-200 KHZ change, because the finger is generated change.
(3) distance: the general distance is not very big, within 0.5 cm.
(4) The density of fingerprints: If there are more fingerprints, you can have an impact on it by doing moving movements on the screen to the finger.
(5) Collection point: it can be any place, including finger surface (glass, clothes, etc.), skin or other objects, etc.
(6) Identification method: generally use capacitive fingerprint reader or laser scanning type fingerprint reader for identification.
Fingerprint use in bank
Sixth, functional characteristics (or feature extraction)
1、Fingerprint identification device: need to be used with the sensor to obtain the correct fingerprint image to complete the identification and extraction of fingerprints.
2、Image processing: The image of fingerprint is processed by software so that fingerprint image and feature information can be obtained.
3、Algorithm: fingerprint feature analysis algorithm: by identifying each feature point on the finger, the features and shape of the fingerprint can be analyzed.
High recognition rate; not affected by finger drying conditions; can collect the complete fingerprint, etc.
4、Feature extraction method: including manual extraction method and artificial intelligence technology.
The former includes operations such as dotting of fingerprint features, while the latter processes them through image recognition technology.
5、Function: functional features (such as pressing to unlock) can be extracted by software or manually.