The so-called biometrics technology is the close combination of high-tech means such as computers and optics, acoustics, biosensors, and biostatistics principles, utilizing the inherent physiological characteristics of the human body (such as fingerprints, face images, irises, etc.) and behavioral features (such as handwriting). , voice, gait, etc.) to identify individuals.
Biometric technology mainly refers to a technology for identity authentication through human biometrics. Human biometric features are often unique, measurable or automatically recognizable and verifiable, heritable, or life-long. Compared with traditional authentication technologies, there are great advantages.
Fingerprint recognition
Fingerprints are lines on the frontal skin of the fingertips. Although the fingerprint is only a small part of human skin, it contains a lot of information. Fingerprint features can be divided into two categories: general features and local features.
The overall characteristics refer to those features that can be observed directly by the human eye, including basic texture patterns, pattern regions, core points, triangle points, pattern lines, and ridge lines. The basic lines are circular, arched, and spiral.
Local features are the features of the nodes on the fingerprint. These nodes with certain characteristics are called feature points. Two fingerprints often have the same overall characteristics, but their local features, feature points, cannot be exactly the same. The feature points on the fingerprint are the endpoints, bifurcation points, and turning points on the fingerprint lines.
Fingerprint recognition technology usually uses fingerprint's overall features such as stripes, triangles, etc. to classify, and then uses local features such as position and direction to identify the user.
Generally, firstly, “find points†are found from the acquired fingerprint image, and then a digital representation of the user's living fingerprint is established based on the characteristics of the characteristic points—fingerprint feature data (a kind of one-way conversion, which can be converted from the fingerprint image into Feature data but cannot be converted from fingerprint data to fingerprint image).
Since the two different fingerprints do not produce the same feature data, the pattern matching between the collected fingerprint image feature data and the fingerprint feature data stored in the database is used to calculate the degree of similarity, and finally two Fingerprint matching results, according to the matching results to identify the user identity. Because each person's fingerprint is different, that is, between the ten fingers of the same person, the fingerprint is also significantly different, so the fingerprint can be used for identification.
advantage
1) Fingerprints are unique features of the human body, and their complexity is sufficient to provide sufficient features for authentication.
2) If you want to increase reliability, just register more fingerprints, identify more fingers, up to ten, and each fingerprint is unique.
3) Scanning fingerprints is fast and very easy to use.
4) When reading the fingerprint, the user must contact the finger and the fingerprint collector. The direct contact with the fingerprint collector is the most reliable way to read human biometrics. This is one of the main reasons why the fingerprint recognition technology can occupy most of the market.
5) Fingerprint capture heads can be more compact and the price can be lower.
Shortcomings
1) The fingerprints of some people or some groups are difficult to image because they have few fingerprint features.
2) In the past, because of the use of fingerprints in criminal records, some people were afraid of "recording fingerprints." However, in fact, the current fingerprint authentication technology can ensure that no data containing a fingerprint image is stored, but only the encrypted fingerprint feature data obtained from the fingerprint is stored.
3) Each time the fingerprint is used, the user's fingerprint imprint is left on the fingerprint collector head, and these fingerprint traces may be used to duplicate the fingerprint.
It can be seen that the fingerprint identification technology is currently the most convenient, reliable, non-invasive and inexpensive biometric technology solution, and the market application has great potential.
Voice recognition
The so-called voiceprint (Voiceprint) is the acoustic spectrum of speech information that is displayed by electroacoustic instruments. The generation of human language is a complex physical and physical process between the body's language center and the vocal organ. The vocal organs used by people in speech—words, teeth, throat, lungs, and nasal cavity—are very different in size and form. , so any two people have different voiceprint patterns. Each person's speech acoustics features both relative stability and variability, which are not absolute and immutable.
This variation can come from physiology, pathology, psychology, simulation, disguise, and also related to environmental disturbances. In spite of this, since everyone has different vocal organs, people can still distinguish between different people's voices or judge whether they are the same person's voice.
Advantages and disadvantages
The application of voiceprint recognition has some disadvantages. For example, the voice of the same person has variability and is vulnerable to physical conditions, age, emotions, etc.; for example, different microphones and channels have an impact on recognition performance; for example, environmental noise interferes with recognition; For example, in the case of a mixed speaker, the human voiceprint feature is not easily extracted.... In spite of this, compared with other biological features, the application of voiceprint recognition has some special advantages:
1) Voices containing voiceprint features are easy and natural to obtain, and voiceprint extraction can be done unknowingly, so users' acceptance is also high;
2) The recognition of the acquired voice is low in cost, simple to use, one microphone is enough, and no additional recording equipment is needed when using the communication device;
3) It is suitable for remote identity verification. It only requires a microphone or telephone, mobile phone to log in remotely through a network (communication network or internet);
4) The algorithm for identifying and confirming voiceprints is low in complexity;
5) With some other measures, such as content recognition through voice recognition, etc., can improve the accuracy; ... and so on. These advantages make the application of voiceprint recognition more and more popular among system developers and users. The world market share of voiceprint recognition is 15.8%, second only to biometric recognition of fingerprints and palm prints, and there is a rising trend.
Retina recognition
The retina is the blood cell layer at the bottom of the eye. Retina scans use low-density infrared to capture the unique features of the retina, and the only pattern of blood cells is captured.
The retinas are very small nerves (1/50th of an inch) in the back of the eyeball. It is an important organ for the human eye to sense light and transmit information through the optic nerve to the brain. It is similar to the film's function and used for biometric identification. The blood vessels are distributed around the nerve retina, which is the farthest point of the four layers of the retina.
advantage
The retina is an extremely fixed biological feature because it is "hidden" and therefore may not wear out, age, or be affected by the disease.
The user does not need to have direct contact with the device.
It is the most difficult system to deceive because the retina is invisible and therefore will not be forged.
Shortcomings
The retina technique has not been tested. It is clear that retinal technology may cause health damage to users, which requires further research. For consumers, retinal technology is not attractive. It is difficult to further reduce its cost.
Iris recognition
Capture the data image of the iris; prepare the process for iris image analysis; create a 512-byte iriscode from the texture or type of iris. Use the iriscode template for confirmation. In today's world, iris recognition is still recognized as the most accurate biometric identification system.
Biometrics is a technique that translates unique human features (such as facial features, sounds, fingerprint features, etc.) into digital codes that can identify and verify identities.
The iris recognition technology recognizes the identity through the characteristics of the unique human eye iris, and the accuracy of the iris feature matching even surpasses the DNA matching.
This technology has been widely considered in the biometrics industry as the most accurate, stable, and highly scalable identification system available today.
advantage
1. Easy to use by the user; 2. Probably the most reliable biometric technology; 3. No physical contact required; 4. High reliability.
Fast and convenient: With this system, you don't need to carry any documents, you can achieve the gate control, one-way or two-way; you can be authorized to control a door, you can also control the opening of multiple doors;
Licensing flexibility: The system can arbitrarily adjust user rights according to the needs of management, and keep abreast of user dynamics, including customer identity, operating location, functions, and time sequence, to realize real-time intelligent management;
Can not copy: The system uses the iris information as a password, can not be copied; and each activity, can be automatically recorded, easy to trace back, query, illegal cases are automatically alarm;
Flexible configuration: Users and managers can set different installation and operation modes according to their preferences, needs or occasions. For example, in public places such as the lobby, only passwords may be used. However, on important occasions, passwords are forbidden. Only iris recognition methods are used. Of course, they can be used in both ways.
Low investment and maintenance-free: The system can retain the original lock, but its mechanical movement is reduced, the movement range is small, and the lifespan of the bolt is longer; the system is maintenance-free, and it can be expanded and upgraded at any time without having to repurchase the equipment. In the long run, the benefits are significant, and the management level can be greatly improved.
Wide range of applications: widely used in coal mines, banks, prisons, access control, social security, medical and other industries;
Shortcomings
1. It is difficult to miniaturize the size of the image acquisition device; 2. The cost of the device is high and it cannot be widely promoted; 3. The lens may produce image distortion and reduce the reliability; 4. Two major modules: hardware and software;
5. An automatic iris recognition system consists of two modules: hardware and software: iris image acquisition device and iris recognition algorithm. Corresponds to the two basic problems of image acquisition and pattern matching, respectively.
face recognition
A widely used regional feature analysis algorithm in face recognition technology. It integrates the computer image processing technology and the principle of biostatistics. It uses computer image processing technology to extract the image feature points from the video and analyzes the principle of biostatistics. Create a mathematical model, which is a face feature template. Using the face profile template that has been built and the subject's face image for feature analysis, a similar value is given based on the results of the analysis. By this value, you can determine whether it is the same person.
Advantage
As a new biometrics technology (Biometrics), face recognition technology has unique advantages in application compared with iris recognition, fingerprint scanning, hand-scanning and other technologies:
Easy to use, the user accepts high-level face recognition technology using a universal camera as the identification information acquisition device, completing the recognition process in a non-contact manner without recognition of the recognition target.
Intuitiveness highlights that the basis used by face recognition technology is the face image of a person, and the face is undoubtedly the most intuitive source of information that can be discerned by the naked eye. It is convenient for manual confirmation and auditing, and “taking people by appearance†is consistent with the cognitive laws of people.
High recognition accuracy and speed Compared with other biometric technologies, the recognition accuracy of face recognition technology is at a high level, and the misrecognition rate and rejection rate are low.
Not easy to counterfeit In applications where high security is required, face recognition technology requires that the recognition object must be in person to identify the scene, and it is difficult for others to counterfeit. The unique discrimination ability of the face recognition technology ensures that others cannot deceive the recognition system with inactive photos, puppets, and wax figures. This is difficult to achieve with fingerprints and other biometric identification technologies. For example, a legitimate user's severed finger can impersonate a legitimate user's identity and make the identification system oblivious.
Using general-purpose devices The devices used in face recognition technology are general PCs, video cameras, and other conventional devices. Since computers, closed-circuit television monitoring systems, etc. have been widely used, the use of face recognition technology is not required for most users. A large number of special equipment, which not only protects the user's original investment but also extends the functionality of the user's existing equipment, to meet the needs of the user's security precautions.
Basic data is easy to obtain Face recognition technology is based on face photographs or real-time ingestion of face images, which is undoubtedly the easiest to obtain.
Low cost, easy to use due to face recognition technology is used in conventional general-purpose equipment, the price is within the acceptable range of the average user, compared with other biometrics, face recognition products have a high performance price ratio.
In a nutshell, face recognition technology is a high-precision, easy-to-use, high-stability, hard-to-counterfeit, and cost-effective biometric recognition technology with an extremely broad market application prospect.
Shortcomings
Facial recognition is considered to be one of the most difficult research topics in the field of biometrics and even artificial intelligence. The difficulty in facial recognition is mainly due to the characteristics of the face as a biological feature.
The difference between similar individuals is not significant, all facial structures are similar, and even the facial organs are structurally similar. This feature is advantageous for positioning with the face, but it is disadvantageous for distinguishing human individuals with the face.
The shape of the volatile face is very unstable, and people can produce a lot of expressions through facial changes. At different viewing angles, the visual image of the face is also very different. In addition, the facial recognition is also subject to lighting conditions (such as day and night, indoor And outdoor, etc.), many face masks (such as masks, sunglasses, hair, beard, etc.), age, and many other factors.
In face recognition, the first type of change is that it should be scaled up as a criterion for distinguishing individuals, while the second type of change should be eliminated because they can represent the same individual. The first type of change is generally referred to as inter-class change, and the second type of change is referred to as intra-class change. For the face, intra-class changes are often greater than inter-class changes, making it difficult to distinguish individuals with inter-class changes in the case of intra-class changes.
Vein recognition
The identification of venous blood vessels is mainly based on the structure. Because the vein pattern contains a large amount of feature information, it can be used as an object of verification.
The principle of palm vein recognition is also the use of venous angiography using different absorption characteristics of infrared light of a specific wavelength between a vein and a muscle or a callus.
The same principle as palm vein recognition. Since the palm of the hand is thick, infrared light is usually not transmitted, so reflection angiography can only be used.
Infrared light shines on the back of the hand, where the veins absorb dark infrared light, and the muscles and bones are strongly reflected, allowing for the contrast of veins.
advantage
1) Belonging to the internal characteristics of the cow, it will not wear out, it is difficult to forge, and it has high security. 2) Vascular features are usually more pronounced, easier to identify, and better in anti-interference. 3) It can realize non-contact measurement, good hygienic and easy for users to accept. 4) Not easily affected by scratches or oil stains on the hand surface.
Shortcomings
1) The back vein of the hand may still change with age and physiological changes. The permanent has not been confirmed. 2) Although the possibility is small, there is still the possibility that the registration may not be successful. 3) Since the collection method is limited by its own characteristics, the product is difficult to miniaturize. 4) The collection equipment has special requirements, the design is relatively complex, and the manufacturing cost is high.
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