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VPR is considered to be what is known as an automated physical biometric. This simply means that no direct contact is required by the end user on a VPR system. So, this classifies VPR as a non contactless biometric technology, thus giving it its great appeal to the public and customers at large. VPR examines for the unique pattern of blood vessels in either the palm or the finger (in this case, multiple fingers can be used).

A question which often gets asked at this point is why are the veins chosen for this particular technology over the arteries? The answer is quite simple, for three primary reasons:

  1. Veins are much larger than the arteries;
  2. Veins are much closer to the surface of the skin, the arteries are located much below the skin surface;
  3. Veins carry deoxygenated blood throughout the entire body.

It is the third feature of the physiology and the anatomy of the veins which form the science behind VPR. For example, in order to extract the unique features of the vein pattern, a Near Infrared Light (NIR) is exposed to either the palm for the fingertips. The hemoglobin absorbs the NIR light. Hemoglobin is merely a pigment in the blood stream which is heavily constituted of iron, and carries oxygen in the bloodstream. It is a fact that the veins in our body which contain hemoglobin has a much lesser concentration of it than the arteries which exist in our body.

The Components Of Vein Pattern Recognition

The actual VPR technology is composed of four major components, which are as follows:

  1. A sensor with Light Emitting Diodes (LED’s) which emit the NIR light as previously described;
  2. A high resolution Charged Couple Device (CCD) camera;
  3. A high resolution Charged Couple Device (CCD) camera;
  4. The database which contains the enrollment and verification templates, as well as a detailed log history of the verification and identification transactions which have transpired during a set period of time.

How Vein Pattern Recognition Works

With a VPR system, the end user can place their either their palm or fingertip within the scanner, and in order to properly position them, guides can be used. The latter part is the only contact which is required, and there is no direct contact with either the palm or the fingertip on the actual sensor itself, thus giving VPR its non contactless feature.

From this point onwards, after the palm or fingertip is properly positioned, the NIR light is then flashed towards the target, and in order to illuminate the unique pattern of blood vessels, two techniques are used, and are described as follows:

  1. Diffused Illumination: With this method, the NIR light source and the sensor are located on the same side of the VPR. As a result, the NIR light which is reflected back from either the palm or the fingertip is then used to capture the raw of the vein pattern. The thickness of the skin is not a factor with this method;
  2. Direct Illumination: With this technique, the NIR light is flashed directly at either the palm or the fingerprint, and through the target. This gives the impression of the ability to see the vein patterns right through the skin. This technique is directly affected by the thickness of the skin. The NIR light can be flashed from either the top, below, or on the sides of the VPR scanner. All three of these have their own set of advantages and disadvantages, which are as follows:
    1. Top lighting: This gives the most robust raw image of the vein patterns, but these lighting units can be large as well as be exposed very quickly to dirt and grime;
    2. Side lighting: This requires extra NIR lighting power as well as much more processing power to capture the raw image of the vein pattern;
    3. Bottom lighting: This is the cheapest option, but it is much more sensitive to the actual NIR light, and for capturing the raw images of the vein pattern originating from a fingertip.

From within the VPR system itself, specialized software is used to normalize the raw images of the vein pattern which has just been captured, and also removes any types of kinds of obstructions such as skin hair on the palms or on the fingertips. The extraction algorithms then extract the unique features on the vein pattern, and the enrollment template remains encrypted in the database of the VPR system.

Vein Pattern Recognition-The Advantages & Disdvantages

Just like fingerprint recognition and hand geometry recognition, VPR can also be rated and compared against the same seven criterion:

  1. Uniqueness: Scientific studies have shown that even identical twins have unique vein patterns and structures;
  2. Universality: VPR technology has an acceptance rating of very near 100%, and is very versatile to use, when compared to the other biometric technologies. For instance, as described, either the palm or multiple fingers can be used, and if need be, even a combination of both the palm and the fingers can be used, thus providing for a very effective multimodal biometric solution;
  3. Permanence: Questions are still being raised if the vein pattern does indeed change in the structure and physiology over the lifetime of an individual, although at the present time, it poses no serious issues for the purposes of verification and identification with VPR technology;
  4. Collectability: VPR technology is very easy to use, manage, as well as deploy. Verification is very quick (less than one second), and since this is a non contactless technology, the raw images of the vein are not at all impacted by dirt on the surface of the skin, cuts, bruises, scars, or even moisture and dryness on the fingertips or the palm. The only variable which can impact the quality of the vein pattern raw image is in the thickness of the skin itself;
  5. Collectability: VPR technology is very easy to use, manage, as well as deploy. Verification is very quick (less than one second), and since this is a non contactless technology, the raw images of the vein are not at all impacted by dirt on the surface of the skin, cuts, bruises, scars, or even moisture and dryness on the fingertips or the palm. The only variable which can impact the quality of the vein pattern raw image is in the thickness of the skin itself;
  6. Performance: VPR possesses two very distinct advantages over the traditional biometric technologies:
    1. The matching algorithms are not at all complex and are also very “compact” in nature, thus the processing and storage demands towards a VPR system is quite low;
    2. The sensor technology has made great advancements, and hence, it has become very small in nature, thus positioning VPR technology as a strong potential to be used for smartphone security;
    3. It should be noted though, that a VPR system can be very prone to the negative effects of ambient light, or light which comes from the external environment;
  7. Acceptability: Because of its non contactless nature, VPR technology is viewed much more as a “hygienic” form of biometric technology (especially in countries like Japan), thus giving VPR its great appeal to customers. There are also virtually no privacy rights or civil liberties issues with VPR technology, because an individual’s vascular pattern is basically invisible to the outside world;
  8. Resistance to circumvention: It is very difficult to spoof a VPR system, because just like the other biometric technologies, a VPR system requires a live subject, because a constant blood flow in the veins is required in order for the raw images to be captured.

Given how well VPR ranks against these seven criterion, as well as its wide public acceptance, it is just a given fact that VPR serves a wide range of markets, as well as specialized markets. The applications that VPR serves are both government and commercial applications. Examples of such include the following:

  1. Confirming the identity of government welfare program recipients;
  2. Using VPR as a Single Sigh On Solution (SSO) for logical access entry, thus eliminating the use of passwords entirely;
  3. VPR is also seeing heavy usage as an SSO at Point of Sale (POS) terminals;
  4. Wide scale usage in physical access entry scenarios (primarily for office building type of entry, VPR is not meant for the harsh environments like warehouses, factories, etc. – this is where hand geometry recognition comes into play);
  5. VPR is also seeing a huge uptick in the usage at the major international airports as a way of quickly and efficiently confirming the identity of passengers via the use of their e-Passport;
  6. VPR is an excellent choice for time/attendance applications for all kinds and types of workforces;
  7. VPR is even being used at car rental places, mini storage units, as well as condominiums and dormitories in universities and colleges.