There are many ways to realize fingerprint identification. Some imitate the traditional methods of comparing local details of fingerprints by public security departments; Some are directly identified by all features; Others use more unique methods, such as the ripple edge pattern of fingerprints and ultrasound. Some devices can measure finger fingerprints in real time, while others cannot. Among all biometric technologies, fingerprint identification is the most widely used one at present.

Fingerprint identification is more suitable for indoor security system, because it can provide sufficient conditions for users to explain and train, and the operating environment of the system is controllable. Because of its relatively low price, small size (it can be easily integrated into the keyboard) and easy integration, almost all applications in the workstation security access control system are fingerprint identification.

2. Palm geometry recognition

Geometric recognition of the palm is realized by measuring the physical characteristics of the user's palm and fingers, and advanced products can also recognize three-dimensional images. As a mature method, geometric recognition of palm is not only good in performance, but also convenient to use. Suitable for a large number of users, or users do not often use it, but it is easy to accept when using it. If necessary, the accuracy of this technology can be very high, and at the same time, the performance of biometric technology can be flexibly adjusted to meet a wide range of use needs. Palmprint reader is widely used and easily integrated into other systems, so it has become the first choice technology for many biometric projects.

3. Voice recognition

Speech recognition is a kind of recognition technology by analyzing the physical characteristics of user's voice. At present, although some speech recognition products have entered the market, they are not convenient to use, mainly because of the great variability of sensors and voices. In addition, compared with other biometric technologies, it uses more complicated steps and is more inconvenient in some occasions. A lot of research work is under way, and we believe that speech recognition technology will make great progress.

4. Retinal recognition

Retinal recognition uses a low-intensity light source emitted by an optical device to scan a unique pattern on the retina. There is evidence that retinal scanning is very accurate, but it requires users to look at the receiver and stare at a point. This is inconvenient for people who wear glasses, close to the receiver and uncomfortable. So although the retina recognition technology itself is very good, the user's acceptance is very low. Therefore, this kind of product is still a non-mainstream biometric product, although it was redesigned in the 1990s to enhance connectivity and improve the user interface.

5. Iris recognition

Iris recognition is a technology that causes less interference to people in biometric identification related to eyes. It uses quite common camera elements and does not require users to touch the machine. In addition, it can achieve higher template matching performance. Therefore, it attracts the attention of all kinds of people. In the past, iris scanning equipment had no advantages in simplicity of operation and system integration, and we hope that the new products can be improved in these aspects.

6. Signature identification

Signature identification has advantages over other biometric technologies in application. People are used to signing as a way to confirm their identity in transactions, and its further development will not make people feel much different. Practice has proved that signature recognition is quite accurate, so the signature can easily become an acceptable identifier. However, compared with other biometric products, such products are currently few in number.

7. Face recognition

This is a very attractive technology, and its performance is often misunderstood. There are often some exaggerated remarks about facial recognition, but it is difficult to achieve in practice. It's one thing to compare two still images, but it's quite another to find and confirm someone's identity in a crowd without attracting others' attention. Some systems claim to be able to do the latter, but they are actually doing the former, but they are not biometrics. It is easy to understand the attraction of facial recognition from the user's point of view, but people's expectations of this technology should be realistic. So far, face recognition has rarely been successful in practical applications. But once the technical obstacles are overcome, it will become an important biometric method.

8. Gene recognition

With the development of human genome project, people have deepened their understanding of gene structure and function and applied it to personal identification. Because among the 6 billion people in the world, there may be people born at the same time or with the same name, similar appearance and the same voice, and fingerprints may disappear, but only genes are the only unchanging signs representing your own genetic characteristics. It is reported that genetic ID cards with personal genetic information have appeared in Sichuan, Hubei and Hong Kong in the form of smart cards.

The first step in making this genetic ID card is to obtain relevant genes, test them, select characteristic loci (DNA fingerprints), and then load them into the central computer repository, thus making a genetic ID card. If you like to add personal medical records and carry out genetic testing, it is also possible. After the genetic ID card is issued, doctors and related medical institutions can use smart card readers to read the medical records of relevant personnel.

Gene recognition is an advanced biometric technology, but due to technical reasons, it can not be sampled in real time and recognized quickly, which limits its wide application to some extent.

In addition to the biometric technology mentioned above, there are also technologies for identification through characteristics such as smell and earlobe. But they can't enter daily life yet.

9. Vein recognition

Vein identification, which uses near infrared ray to read the vein pattern and compare it with the stored vein pattern to carry out personal identification technology. PalmSecure from Fujitsu? Using this technology, people can be identified from a position far away from the identification device by shooting with near infrared rays and comparing with pre-stored vein patterns.

10. Gait recognition

Gait recognition, which uses the camera to collect the image sequence of human walking process, compares it with the stored data after processing, and achieves the purpose of identity recognition. The Institute of Automation of China Academy of Sciences has conducted some research. However, there are still many problems that restrict its development, such as the change of shooting angle, the different clothes of the recognized person, the different things they carry, and the change of contour extraction of the captured image will affect the recognition effect. However, this identification technology can realize long-distance identification and is outstanding in active defense. If we can break through the existing limitations, it will be useful in practical application.