An introduction to Vein Pattern Recognition
Vein Pattern Recognition, also known as “VPR” for short, is the latest biometric technology to be developed and come out into the marketplace.
Since the palm is considered to be just directly underneath the hand, it is also being used as a complement to Hand Geometry Recognition as a multimodal security solution.
In fact, Vein Pattern Recognition is giving serious competition to the most traditional modalities, such as that of Fingerprint Recognition and Iris Recognition.
It is also considered to be what is known as an “Automated Physical Biometric.”
This simply means that Vein Pattern Recognition is a non-contactless type of modality. In other words, there is no direct contact required by the individual to collect the raw images of the veins.
Thus, this makes it extremely appealing to the public at large, and potential customers who are interested in using biometric technology for security purposes.
In exploring the usage of Vein Pattern Recognition, the question of using veins instead of the arteries often gets asked. There are three primary reasons for this:
- The veins in the human body are much larger than the arteries;
- The vein structure is much closer to the surface of the skin, whereas the arteries are located much below the skin surface;
- Veins carry deoxygenated blood throughout the entire human body. This allows for much more robust images of the vein structure to be captured by the device.
The science behind Vein Pattern Recognition
It is the third feature (as listed above) which forms the science behind Vein Pattern Recognition.
To fully extract the unique features of the vein pattern (whether it is in the palm or the fingerprint), a Near Infrared (also known as “NIR”) light is exposed to the area in question.
The haemoglobin in the blood stream absorbs this NIR light. The haemoglobin is the pigment in the blood stream, which is primarily composed of iron, which carries the oxygen in the bloodstream.
The veins contain a much lesser concentration of haemoglobin than what the arteries possess. Because of this, the veins absorb a much higher level of the NIR light.
Thus, the raw images appear much darker and more robust when they are captured by the Vein Recognition device. At this point, the question often gets asked as to how the veins obtain their unique patterns.
Just like the pattern of blood vessels which form the retina, the unique patterns associated with the veins are created and formed within the first eight weeks of gestation.
The components of Vein Pattern Recognition consist of four main elements, which are as follows:
- On the device, there is a sensor which consists of a series of Light Emitting Diodes (also known as “LEDs”). These LEDs emit the NIR light to the surface of the palm or fingerprint.
- A high-resolution Charge-Coupled camera.
- A separate processing unit which extracts the unique pattern of the blood vessels from either the fingerprint or the palm.
- The biometrics database which contains both the Enrolment and the Verification templates. Also, a detailed log history is kept in this database which displays the history of the Verification and/or Identification transactions which have transpired during a pre-established time period.
In Part 2 of this series, Ravi Das will continue with the topic of Vein Pattern Recognition.