Finger veins, the tiny blood vessels inside your finger, are laid out in a pattern which is unique to every individual. Fingerprints have been used for more than a century now for identification. However, finger vein based identity recognition systems might soon surge ahead based on the unique advantages they offer.
In this article I will discuss how finger vein based biometric authentication technology is poised to give fingerprints tough competition in the race to be termed as the ideal biometric for authentication systems.
Biometric authentication: a comparison of fingerprint, finger vein and other modalities
The term biometrics is short for biological measurable characteristics. So, any physical human trait which is unique for every individual and is measurable can be termed as a biometrics. Biometric authentication is simply authentication driven by biometrics.
When you need to gain access of a resource online or in person, then using your unique biometric measurements your identity can be validated. Biometric traits such as fingerprints, gait, face recognition, iris structure, retina etc. are all candidate technologies for biometric authentication.
Fingerprints recognition based systems, however, have a lead over other technologies. The primary reason for this early gain was that fingerprints themselves have been used by law enforcement agencies for more than a century for identification. So, the standards and measures for capturing and comparing fingerprints were well established much earlier than other biometrics. As a result, they became the natural first choice for computerized identity and access management systems.
Let us now take a look at how fingerprint and finger vein based authentication systems work.
Fingerprint based biometric authentication
Fingerprint ridge patterns are unique for every individual. Fingerprint based authentication systems capture these intricate ridge patterns digitally and then determine whether the person presenting himself has access permission or not. Based on this decision, he is allowed to proceed or turned back where in he may be allowed to make another attempt at authenticating himself.
Biometric fingerprint-based authentication systems follow the following process to validate the authenticity of the subject presenting his fingerprints for authentication –
Enrolment of valid subjects
All the valid subjects, who have access to one or more areas in the institution being secured, get themselves enrolled in the system. There is a procedure established for enrolment wherein the subjects get their fingers scanned.
The fingerprints captured are stored in biometric database in the form of biometric templates. Biometric templates are encoded descriptions of the finger ridge patterns and help in digital storage and comparison of the fingerprints. The biometric database is thus the central repository of fingerprint scans of all the members of the institution who can potentially access its facilities.
Fingerprint scan for authenticating
This step refers to the subject presenting himself for gaining access. He puts his hand on a fingerprint scanner. The scanner then scans his fingerprints and convert them to their biometric template equivalent.
Matching with the ones stored in the biometric database
The biometric template captured from the subject in step 2 will then be compared to all the stored biometric templates in the central database. If a match is found, then the identity of the subject will be established and he will be allowed to enter. If there is no match found in the biometric database, then the subject can be asked to make a re-attempt or will be turned back.
Fingerprint based biometric authentication systems have started gaining quick acceptance due to their advantages over the access badge. Biometrics such as fingerprints cannot be stolen or misplaced like an access badge can be. One cannot lend a finger to a friend or colleague for buddy punching which is a common malpractice with access badges. It is very difficult, if not impossible, to forge a fingerprint.
With its inherent advantages, and the gradual reduction in prices of fingerprint scanning devices, fingerprint-based authentication systems provide a much better authentication solution.
Finger-vein based biometric authentication
Hitachi chanced upon the finger vein recognition technology when they observed that near-infrared light could be used to scan finger vein patterns. They started seriously investigating this technology in 1997. It was in 2004 that they came out with commercial ATM systems using finger vein recognition technology.
Finger vein technology is similar in-principle with fingerprint technology. Both the technologies enroll subjects and store the finger print/vein patterns as biometric templates in database. This database is then used to authenticate subjects presenting themselves at the authentication points.
There is a however a key difference between the two technologies. Fingerprints are composed of ridge pattern on the surface of the finger. Finger veins, on the other hand, are sub-dermal or below the skin. Due to this reason finger vein image capture cannot be done using straightforward image capture as is done in the case of fingerprint scans. Instead a near-infrared light beam is shone on one side of the finger which travels through the finger and traces out or highlights the vein pattern. This vein pattern is then captured as an image on the other side of the finger using a special camera.
The sub-dermal nature of finger veins leads to certain inherent advantage in scanning them as opposed to fingerprint scanning.
Let us have a look at what are the advantages of finger-vein based authentication systems as compared to fingerprint based systems.
Fingerprint versus finger vein biometric authentication
Finger vein authentication technology offers certain key advantages over fingerprint based technology –
Finger vein based authentication is more accurate
Finger vein recognition is more accurate than fingerprint recognition systems and has lower False Rejection Rate (FRR) as well as lower False Acceptance Rate (FAR).
Finger vein authentication is less invasive technology
Finger vein recognition technology doesn’t require the subject to place his finger in contact with the scanning surface. So, there are no hygiene issues related to finger vein scanning. Fingerprint recognition systems, on the other hand, do require the subject to press his finger on the scanning surface. As a result, finger vein recognition is less invasive than fingerprint based authentication technology.
Finger veins do not leave latent prints behind on the scanning surface
Finger vein based authentication technology does not require the subject to touch the scanning surface. Hence, he doesn’t leave any latent prints behind. So, there is no possibility of duplication by forging or lifting. Such forgery, however, is possible in fingerprint-based technology as the subject does press his finger on the scanning surface.
Finger vein authentication is not affected by weather or age related effects on the skin surface
Since finger veins are sub-dermal, they are not affected by wet or dry weather. They are also unaffected by age related wrinkling. As a result, finger vein scans once used for enrolment can be used for the whole lifetime of the subject. However, fingerprint based authentication’s performance and accuracy is affected by age and weather conditions as fingerprints are located on the skin surface.
Finger vein authentication technology requires less maintenance
Fingerprint authentication technology requires contact with the scanning surface. As a result, regular cleaning of the scanner surface is required to maintain image capture quality. This requires dedicated maintenance at regular intervals. Finger vein authentication technology is contactless and requires no maintenance on a regular basis.
Hybrid finger-based biometric authentication
Despite the inherent advantages that finger vein based authentication technology provides over fingerprint based ones, its biometric template is of a bigger size than that of the latter.
Moreover, authentication and processing speed varies between the two technologies. While finger vein technology is better suited for 1:1 searches, fingerprint technology is better suited to 1: N searches.
This has led to the development of hybrid and contactless scanners which scan both fingerprint and finger veins simultaneously. Hybrid scanning is effective with both dry or wet fingers as well as instable bloodstreams. In addition, multi-modal scanning of fingerprint and finger vein provides very high accuracy.
There is no doubt that finger vein based authentication technology has some inherent advantages over fingerprint based technology such as accuracy and non-invasiveness among others. However, the potential limitation of supporting only one of 1:1 and 1:N scanning in either of the two modes, has led to development of multi-modal fingerprint and finger vein simultaneous scanning devices. However, it remains to be seen, whether finger vein based scanners gain more popularity or hybrid scanners.
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