Six biometric technology principles and advantages and disadvantages

The so-called biometric technology is the close integration of computers with high-tech methods such as optics, acoustics, biosensors and biostatistics, and the use of inherent physiological characteristics of the human body (such as fingerprints, facial features, iris, etc.) and behavioral characteristics (such as handwriting) , Voice, gait, etc.) for personal identification. Biometrics mainly refers to a technology that uses human biometrics for identity authentication. Human biometrics usually have the characteristics of uniqueness, measurable or automatic identification and verification, heredity or lifelong change, so biometric authentication technology Compared with traditional authentication technology, there are greater advantages. Fingerprint recognition principle Fingerprints are the uneven lines on the skin on the front of the finger. Although fingerprints are only a small part of human skin, they contain a lot of information. Fingerprint features can be divided into two categories: overall features and local features. The overall feature refers to those features that can be directly observed with the human eye, including basic patterns, pattern areas, core points, triangle points, pattern lines and lines, etc. The basic grain patterns are ring, arc, and spiral. Local features are the features of nodes on the fingerprint, and these nodes with a certain feature are called feature points. Two fingerprints often have the same overall characteristics, but their local characteristics—feature points—cannot be exactly the same. The characteristic points on the fingerprint are the end points, bifurcation points and turning points on the fingerprint pattern. Fingerprint recognition technology usually uses the overall characteristics of fingerprints, such as patterns, triangles, etc., to classify, and then uses local features such as location and direction to identify users. Usually, first find the "feature point" (minutiae) from the acquired fingerprint image, and then establish the digital representation of the user's live fingerprint based on the characteristics of the feature point-fingerprint feature data (a one-way conversion that can be converted from the fingerprint image to Feature data but cannot be converted from feature data to fingerprint image). Since two different fingerprints will not produce the same feature data, by pattern matching the feature data of the collected fingerprint image and the fingerprint feature data stored in the database, the degree of similarity between them is calculated, and finally two The fingerprint matching result is used to identify the user's identity based on the matching result. Since each person's fingerprints are different, there are obvious differences between the ten fingers of the same person, so fingerprints can be used for identification. 1. Advantages of fingerprint recognition 1) Fingerprints are unique features of the human body, and their complexity is sufficient to provide sufficient features for identification. 2) If you want to increase reliability, you only need to register more fingerprints and identify more fingers, up to ten, and each fingerprint is unique. 3) The speed of scanning fingerprints is very fast and it is very convenient to use. 4) When reading fingerprints, users must touch their fingers with the fingerprint collector. Direct contact with the fingerprint collector is the most reliable way to read human biometrics. This is one of the main reasons that fingerprint recognition technology can occupy most of the market. 5) The fingerprint collection head can be more miniaturized, and the price will be lower. 2. Disadvantages of fingerprint recognition 1) The fingerprints of some people or groups of people are difficult to image because of the few fingerprint features. 2) In the past, because fingerprints were used in criminal records, some people were afraid of "recording fingerprints". However, in fact, the current fingerprint authentication technology can guarantee that it does not store any data containing the fingerprint image, but only stores the encrypted fingerprint characteristic data obtained from the fingerprint. 3) Every time a fingerprint is used, the user's fingerprint print will be left on the fingerprint collector, and these fingerprint traces may be used to copy fingerprints. It can be seen that fingerprint identification technology is currently the most convenient, reliable, non-invasive and cheap biometric technology solution, and its market application has great potential. Voice recognition principle The so-called voiceprint (Voiceprint) is the sound wave spectrum that carries verbal information displayed by electro-acoustic instruments. The production of human language is a complex physiological and physical process between the human body’s language center and the vocal organs. The vocal organs used in speech--the tongue, teeth, larynx, lungs, and nasal cavity are very different in size and shape. , So the voiceprint patterns of any two people are different. The acoustic characteristics of each person’s voice have both relative stability and variability, and they are not absolute and static. This variation can come from physiology, pathology, psychology, simulation, disguise, and is also related to environmental interference. Nevertheless, because everyone’s vocal organs are different, under normal circumstances, people can still distinguish the voices of different people or judge whether they are the same. Pros and cons The application of voiceprint recognition has some disadvantages. For example, the voice of the same person is volatile and easily affected by physical condition, age, emotion, etc.; for example, different microphones and channels have an impact on recognition performance; for example, environmental noise interferes with recognition; Another example is that in the case of mixed speakers, it is not easy to extract the features of human voiceprints; ... etc. Nevertheless, compared with other biological characteristics, the application of voiceprint recognition has some special advantages: 1) The voice acquisition with voiceprint features is convenient and natural, and the voiceprint extraction can be completed unconsciously, so the user's acceptance is also high; 2) Low cost of voice recognition, simple to use, just one microphone, and no need for additional recording equipment when using communication equipment; 3) It is suitable for remote identity confirmation. Only a microphone or phone or mobile phone can be used to realize remote login through the network (communication network or Internet); 4) The algorithm complexity of voiceprint recognition and confirmation is low; 5) Cooperating with some other measures, such as content identification through voice recognition, etc., the accuracy rate can be improved; ... etc. These advantages make the application of voiceprint recognition more and more favored by system developers and users. The world market share of voiceprint recognition is 15.8%, second only to fingerprint and palmprint biometric recognition, and has a rising trend. Retina recognition The retina is the layer of blood cells at the bottom of the eye. Retinal scanning uses low-density infrared to capture the unique characteristics of the retina, and the only pattern of blood cells is thus captured. The retina is a very small nerve (1/50 of an inch) located at the back of the eyeball. It is an important organ for the human eye to receive light and transmit information to the brain through the optic nerve. Its function is similar to that of film and is used for biometric identification. The blood vessels are distributed around the neural retina, the farthest of the four layers of cells in the retina. Advantages of Retina Technology The retina is an extremely fixed biological feature. Because it is "hidden", it cannot be worn, aged or affected by disease. The user does not need to make direct contact with the device. It is the most difficult system to deceive because the retina is invisible, so it cannot be forged. Disadvantages of retina technology Retina technology has not been tested in any way. Obviously, retinal technology may bring health damage to users, which requires further research. For consumers, retina technology is not attractive. It is difficult to further reduce its cost. Iris recognition principle Capture data image of iris Preparation process for image analysis of iris Create a 512-byte iriscode from the texture or type of the iris. Use the iriscode template for confirmation. In today's world, iris recognition is still recognized as the most accurate biometric system. Biometrics is a technology that translates unique human features (such as facial features, voice, fingerprint features, etc.) into digital codes, which can identify and verify identity. The iris recognition technology uses the unique characteristics of the iris of the human eye to identify identity, and the accuracy of iris feature matching even exceeds DNA matching. This technology has been widely recognized in the biometric industry as the most accurate, stable, and upgradable identification system. advantage 1. Easy for users to use; 2. Probably the most reliable biometric technology; 3. No physical contact required; 4. High reliability. Fast and convenient: With this system, door control can be achieved without any documents, which can be one-way or two-way; it can be authorized to control one door or control to open multiple doors; Flexible authorization: The system can adjust user rights arbitrarily according to the needs of management, and understand user dynamics at any time, including customer identity, operation location, function and time sequence, etc., to achieve real-time intelligent management; Unable to copy: This system uses iris information as the password and cannot be copied; and every activity can be automatically recorded for easy traceability and inquiries, and an automatic alarm will be issued for illegal situations; Flexible configuration: Users and managers can set different installation and operation methods according to their own preferences, needs or occasions. For example, in public places such as lobby, you can only use the password input method, but in important occasions, it is forbidden to use the password, and only the iris recognition method is used. Of course, the two methods can also be used at the same time; Low investment and maintenance-free: Assemble this system can retain the original lock, but its mechanical moving parts are reduced, and the movement range is small, and the life of the door bolt is longer; the system is maintenance-free, and can be expanded and upgraded at any time without repurchasing 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; Disadvantage 1. It is difficult to miniaturize the size of image acquisition equipment; 2. The equipment cost is high and cannot be widely promoted; 3. The lens may produce image distortion and reduce reliability; 4. Two modules: hardware and software; 5. An automatic iris recognition system includes two major modules: hardware and software: iris image acquisition device and iris recognition algorithm. They correspond to the two basic problems of image acquisition and pattern matching respectively. face recognition principle A regional feature analysis algorithm widely used in face recognition technology. It combines computer image processing technology with the principles of biostatistics. It uses computer image processing technology to extract feature points from the video and analyzes using the principles of biostatistics. Build a mathematical model, that is, a facial feature template. Use the built-up face feature template and the face of the subject to perform feature analysis, and give a similar value based on the analysis result. This value can be used to determine whether it is the same person. Advantages of face recognition technology Face recognition is an emerging biometrics technology (Biometrics). Compared with iris recognition, fingerprint scanning, palm scanning and other technologies, face recognition technology has unique advantages in application: Easy to use, user-accepted face recognition technology uses a universal camera as an identification information acquisition device, and completes the identification process in a non-contact manner without the identification object being noticed. Intuitiveness highlights the basis used by face recognition technology is the human facial image, and the human face is undoubtedly the most intuitive information source that can be distinguished by the naked eye, which is convenient for manual confirmation and auditing, and "judge a person by appearance" conforms to the law of human cognition. The recognition accuracy is high and the speed is fast. Compared with other biological recognition technologies, the recognition accuracy of face recognition technology is at a higher level, and the false recognition rate and rejection rate are lower. Not easy to counterfeit In applications with high security requirements, face recognition technology requires that the recognition object must be at the recognition site in person, and it is difficult for others to counterfeit. The unique active discrimination ability of face recognition technology ensures that others cannot fool the recognition system with inactive photos, puppets, and wax figures. This is difficult to achieve with biometric technology such as fingerprints. For example, using the severed finger of a legitimate user can impersonate the identity of a legitimate user and make the identification system undetectable. General-purpose equipment The equipment used in face recognition technology is general PCs, cameras and other conventional equipment. Since computers and closed-circuit television monitoring systems have been widely used, there is no need for most users to use face recognition technology. A large number of special equipment not only protects the user's original investment, but also expands the functions of the user's existing equipment, and meets the user's security requirements. The basic information is easy to obtain. The basis used by the face recognition technology is face photos or face images taken in real time, so it is undoubtedly the easiest to obtain. Low cost and easy to popularize. Because the face recognition technology uses conventional general-purpose equipment, the price is within the acceptable range of general users. Compared with other biometric technology, face recognition products have a high performance price ratio. In a nutshell, face recognition technology is a high-precision, easy-to-use, high-stability, difficult-to-counterfeit, and cost-effective biometric recognition technology, which has extremely broad market application prospects. Disadvantage Facial recognition is considered to be one of the most difficult research topics in the field of biometrics and even artificial intelligence. The difficulty of facial recognition is mainly caused by the characteristics of the face as a biological feature. There is little difference between individuals with different similarities. All facial structures are similar, and even facial organs are very similar in structure and appearance. Such a feature is advantageous for using faces for positioning, but it is disadvantageous for using faces to distinguish human individuals. The appearance of a variable face is very unstable. People can produce many expressions through changes in the face. In different viewing angles, the visual image of the face is also very different. In addition, facial recognition is also affected by lighting conditions (such as day and night, indoor And outdoor, etc.), many face coverings (such as masks, sunglasses, hair, beards, etc.), age and other factors. In facial recognition, the first type of changes should be amplified and used as a criterion for distinguishing individuals, while the second type of changes should be eliminated because they can represent the same individual. Usually the first type of change is called the inter-class change, and the second type of change is called the intra-class change. For faces, intra-class changes are often greater than inter-class changes, which makes it extremely difficult to distinguish individuals by using intra-class changes when disturbed by intra-class changes. Vein recognition It mainly uses the structure of veins to perform identity recognition. Since the vein pattern contains a large amount of characteristic information, it can be used as a verification object. The principle of palm vein recognition is to use the different absorption characteristics of specific wavelengths of infrared light between veins, muscles, and bones to perform venous angiography. The principle is the same as that of palm vein recognition. Due to the thick palm of the hand, infrared light is usually not transmitted, so reflection imaging can only be used. Infrared light is irradiated on the back of the hand, the part with veins absorbs infrared light and the reflection is dim, and the reflection of muscles and bones is strong, so as to realize the imaging of the veins. advantage 1) It belongs to the internal characteristics, will not wear out, is difficult to forge, and has high security. 2) Vessel characteristics are usually more obvious, easy to identify, and good anti-interference. 3) Non-contact measurement can be realized, with good hygiene and easy acceptance by users. 4) Not easily affected by scratches or oil stains on the hand surface. Disadvantage 1) The veins of the dorsal hand may still change with age and physiological changes, and the permanence has not been confirmed 2) Although the possibility is small, there is still the possibility that the registration cannot be successfully registered. 3) Because the collection method is limited by its own characteristics, it is difficult to miniaturize the product. 4) The collection equipment has special requirements, the design is relatively complicated, and the manufacturing cost is high.

The so-called biometric technology is the close integration of computers with high-tech methods such as optics, acoustics, biosensors, and biostatistics, and the use of inherent physiological characteristics of the human body (such as fingerprints, facial features, iris, etc.) and behavioral characteristics (such as handwriting), Voice, gait, etc.) for personal identification.

Biometrics mainly refers to a technology that uses human biometrics for identity authentication. Human biometrics usually have the characteristics of uniqueness, measurable or automatic identification, and verification, heredity, or lifelong change, so biometric authentication technology Compared with traditional authentication technology, there are greater advantages.

Principle

Fingerprints are the uneven lines on the skin on the front of the finger. Although fingerprints are only a small part of human skin, they contain a lot of information. Fingerprint features can be divided into two categories: overall features and local features.

The overall feature refers to those features that can be directly observed with the human eye, including basic patterns, pattern areas, core points, triangle points, pattern lines, and lines, etc. The basic grain patterns are ring, arc, and spiral.

Local features are the features of nodes on the fingerprint, and these nodes with a certain feature are called feature points. Two fingerprints often have the same overall characteristics, but their local characteristics—feature points—can not be exactly the same. The characteristic points on the fingerprint are the endpoints, bifurcation points, and turning points on the fingerprint pattern.

Fingerprint recognition technology usually uses the overall characteristics of fingerprints, such as patterns, triangles, etc., to classify, and then uses local features such as location and direction to identify users.

Usually, first, find the “feature point” (minutiae) from the acquired fingerprint image, and then establish the digital representation of the user’s live fingerprint based on the characteristics of the feature point-fingerprint feature data (a one-way conversion that can be converted from the fingerprint image to Feature data but cannot be converted from feature data to fingerprint image).

Since two different fingerprints will not produce the same feature data, by pattern matching the feature data of the collected fingerprint image and the fingerprint feature data stored in the database, the degree of similarity between them is calculated, and finally two The fingerprint matching result is used to identify the user’s identity based on the matching result. Since each person’s fingerprints are different, there are obvious differences between the ten fingers of the same person, so fingerprints can be used for identification.

1. Advantages of fingerprint recognition

1) Fingerprints are unique features of the human body, and their complexity is sufficient to provide sufficient features for identification.

2) If you want to increase reliability, you only need to register more fingerprints and identify more fingers, up to ten, and each fingerprint is unique.

3) The speed of scanning fingerprints is very fast and it is very convenient to use.

4) When reading fingerprints, users must touch their fingers with the fingerprint collector. Direct contact with the fingerprint collector is the most reliable way to read human biometrics. This is one of the main reasons that fingerprint recognition technology can occupy most of the market.

5) The fingerprint collection head can be more miniaturized, and the price will be lower.

2. Disadvantages of fingerprint recognition

1) The fingerprints of some people or groups of people are difficult to image because of the few fingerprint features.

2) In the past, because fingerprints were used in criminal records, some people were afraid of “recording fingerprints”. However, in fact, the current fingerprint authentication technology can guarantee that it does not store any data containing the fingerprint image, but only stores the encrypted fingerprint characteristic data obtained from the fingerprint.

3) Every time a fingerprint is used, the user’s fingerprint print will be left on the fingerprint collector, and these fingerprint traces may be used to copy fingerprints.

It can be seen that fingerprint identification technology is currently the most convenient, reliable, non-invasive, and cheap biometric technology solution, and its market application has great potential.

Voice recognition

The so-called voiceprint (Voiceprint) is the sound wave spectrum that carries verbal information displayed by electro-acoustic instruments. The production of human language is a complex physiological and physical process between the human body’s language center and the vocal organs. The vocal organs used in speech–the tongue, teeth, larynx, lungs, and nasal cavity are very different in size and shape. , So the voiceprint patterns of any two people are different. The acoustic characteristics of each person’s voice have both relative stability and variability, and they are not absolute and static.

This variation can come from physiology, pathology, psychology, simulation, disguise, and is also related to environmental interference. Nevertheless, because everyone’s vocal organs are different, under normal circumstances, people can still distinguish the voices of different people or judge whether they are the same.

Pros and cons

The application of voiceprint recognition has some disadvantages. For example, the voice of the same person is volatile and easily affected by a physical condition, age, emotion, etc.; for example, different microphones and channels have an impact on recognition performance; for example, environmental noise interferes with recognition; Another example is that in the case of mixed speakers, it is not easy to extract the features of human voiceprints; … etc. Nevertheless, compared with other biological characteristics, the application of voiceprint recognition has some special advantages:

1) The voice acquisition with voiceprint features is convenient and natural, and the voiceprint extraction can be completed unconsciously, so the user’s acceptance is also high;

2) Low cost of voice recognition, simple to use, just one microphone, and no need for additional recording equipment when using communication equipment;

3) It is suitable for remote identity confirmation. Only a microphone or phone or mobile phone can be used to realize remote login through the network (communication network or Internet);

4) The algorithm complexity of voiceprint recognition and confirmation is low;

5) Cooperating with some other measures, such as content identification through voice recognition, etc., the accuracy rate can be improved; … etc. These advantages make the application of voiceprint recognition more and more favored by system developers and users. The world market share of voiceprint recognition is 15.8%, second only to fingerprint and palmprint biometric recognition, and has a rising trend.

Retina recognition

The retina is the layer of blood cells at the bottom of the eye. Retinal scanning uses low-density infrared to capture the unique characteristics of the retina, and the only pattern of blood cells is thus captured.

The retina is a very small nerve (1/50 of an inch) located at the back of the eyeball. It is an important organ for the human eye to receive light and transmit information to the brain through the optic nerve. Its function is similar to that of film and is used for biometric identification. The blood vessels are distributed around the neural retina, the farthest of the four layers of cells in the retina.

Advantages of Retina Technology

The retina is an extremely fixed biological feature. Because it is “hidden”, it cannot be worn, aged, or affected by the disease.

The user does not need to make direct contact with the device.

It is the most difficult system to deceive because the retina is invisible, so it cannot be forged.

Disadvantages of retina technology

Retina technology has not been tested in any way.

Obviously, retinal technology may bring health damage to users, which requires further research.

For consumers, retina technology is not attractive.

It is difficult to further reduce its cost.

Iris recognition

Capture data image of the iris

The preparation process for image analysis of iris

Create a 512-byte iris code from the texture or type of the iris.

Use the iris code template for confirmation.

In today’s world, iris recognition is still recognized as the most accurate biometric system.

Biometrics is a technology that translates unique human features (such as facial features, voice, fingerprint features, etc.) into digital codes, which can identify and verify identity.

The iris recognition technology uses the unique characteristics of the iris of the human eye to identify identity, and the accuracy of iris feature matching even exceeds DNA matching.

This technology has been widely recognized in the biometric industry as the most accurate, stable, and upgradable identification system.

 

Advantage

1. Easy for users to use;

2. Probably the most reliable biometric technology;

3. No physical contact required;

4. High reliability.

Fast and convenient: With this system, door control can be achieved without any documents, which can be one-way or two-way; it can be authorized to control one door or control to open multiple doors;

Flexible authorization: The system can adjust user rights arbitrarily according to the needs of management, and understand user dynamics at any time, including customer identity, operation location, function and time sequence, etc., to achieve real-time intelligent management;

Unable to copy: This system uses iris information as the password and cannot be copied, and every activity can be automatically recorded for easy traceability and inquiries, and an automatic alarm will be issued for illegal situations;

Flexible configuration: Users and managers can set different installation and operation methods according to their own preferences, needs, or occasions. For example, in public places such as the lobby, you can only use the password input method, but on important occasions, it is forbidden to use the password, and only the iris recognition method is used. Of course, the two methods can also be used at the same time;

Low investment and maintenance-free: Assemble this system can retain the original lock, but its mechanical moving parts are reduced, and the movement range is small, and the life of the door bolt is longer; the system is maintenance-free, and can be expanded and upgraded at any time without repurchasing 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;

Disadvantage

1. It is difficult to miniaturize the size of image acquisition equipment;

2. The equipment cost is high and cannot be widely promoted;

3. The lens may produce image distortion and reduce reliability;

4. Two modules: hardware and software;

5. An automatic iris recognition system includes two major modules: hardware and software: iris image acquisition device and iris recognition algorithm. They correspond to the two basic problems of image acquisition and pattern matching respectively.

face recognition

A regional feature analysis algorithm widely used in face recognition technology. It combines computer image processing technology with the principles of biostatistics. It uses computer image processing technology to extract feature points from the video and analyzes using the principles of biostatistics. Build a mathematical model, that is, a facial feature template. Use the built-up face feature template and the face of the subject to perform feature analysis, and give a similar value based on the analysis result. This value can be used to determine whether it is the same person.

Advantages of face recognition technology

Face recognition is an emerging biometrics technology (Biometrics). Compared with iris recognition, fingerprint scanning, palm scanning, and other technologies, face recognition technology have unique advantages in the application.

Easy to use, user-accepted face recognition technology uses a universal camera as an identification information acquisition device and completes the identification process in a non-contact manner without the identification object being noticed.

Intuitiveness highlights the basis used by face recognition technology is the human facial image, and the human face is undoubtedly the most intuitive information source that can be distinguished by the naked eye, which is convenient for manual confirmation and auditing, and “judge a person by appearance” conforms to the law of human cognition.

The recognition accuracy is high and the speed is fast. Compared with other biological recognition technologies, the recognition accuracy of face recognition technology is at a higher level, and the false recognition rate and rejection rate are lower.

Not easy to counterfeit In applications with high-security requirements, face recognition technology requires that the recognition object must be at the recognition site in person, and it is difficult for others to counterfeit. The unique active discrimination ability of face recognition technology ensures that others cannot fool the recognition system with inactive photos, puppets, and wax figures. This is difficult to achieve with biometric technology such as fingerprints. For example, using the severed finger of a legitimate user can impersonate the identity of a legitimate user and make the identification system undetectable.

General-purpose equipment The equipment used in face recognition technology is general PCs, cameras, and other conventional equipment. Since computers and closed-circuit television monitoring systems have been widely used, there is no need for most users to use face recognition technology. A large number of special equipment not only protects the user’s original investment, but also expands the functions of the user’s existing equipment, and meets the user’s security requirements.

The basic information is easy to obtain. The basis used by the face recognition technology is face photos or face images taken in real-time, so it is undoubtedly the easiest to obtain.

Low cost and easy to popularize. Because the face recognition technology uses conventional general-purpose equipment, the price is within the acceptable range of general users. Compared with other biometric technology, face recognition products have a high-performance price ratio.

In a nutshell, face recognition technology is a high-precision, easy-to-use, high-stability, difficult-to-counterfeit, and cost-effective biometric recognition technology, which has extremely broad market application prospects.

Disadvantage

Facial recognition is considered to be one of the most difficult research topics in the field of biometrics and even artificial intelligence. The difficulty of facial recognition is mainly caused by the characteristics of the face as a biological feature.

There is little difference between individuals with different similarities. All facial structures are similar, and even facial organs are very similar in structure and appearance. Such a feature is advantageous for using faces for positioning, but it is disadvantageous for using faces to distinguish human individuals.

The appearance of a variable face is very unstable. People can produce many expressions through changes in the face. In different viewing angles, the visual image of the face is also very different. In addition, facial recognition is also affected by lighting conditions (such as day and night, indoor And outdoor, etc.), many face coverings (such as masks, sunglasses, hair, beards, etc.), age, and other factors.

In facial recognition, the first type of change should be amplified and used as a criterion for distinguishing individuals, while the second type of changes should be eliminated because they can represent the same individual. Usually, the first type of change is called the inter-class change, and the second type of change is called the intra-class change. For faces, intra-class changes are often greater than inter-class changes, which makes it extremely difficult to distinguish individuals by using intra-class changes when disturbed by intra-class changes.

Vein recognition

It mainly uses the structure of veins to perform identity recognition. Since the vein pattern contains a large amount of characteristic information, it can be used as a verification object.

The principle of palm vein recognition is to use the different absorption characteristics of specific wavelengths of infrared light between veins, muscles, and bones to perform venous angiography.

The principle is the same as that of palm vein recognition. Due to the thick palm of the hand, infrared light is usually not transmitted, so reflection imaging can only be used.

Infrared light is irradiated on the back of the hand, the part with veins absorbs infrared light and the reflection is dim, and the reflection of muscles and bones is strong, so as to realize the imaging of the veins.

advantage

1) It belongs to the internal characteristics, will not wear out, is difficult to forge, and has high security.

2) Vessel characteristics are usually more obvious, easy to identify, and good anti-interference.

3) Non-contact measurement can be realized, with good hygiene and easy acceptance by users.

4) Not easily affected by scratches or oil stains on the hand surface.

Disadvantage

1) The veins of the dorsal hand may still change with age and physiological changes, and the permanence has not been confirmed

2) Although the possibility is small, there is still the possibility that the registration cannot be successfully registered.

3) Because the collection method is limited by its own characteristics, it is difficult to miniaturize the product.

4) The collection equipment has special requirements, the design is relatively complicated, and the manufacturing cost is high.

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