What is Biometrics ?
Biometrics is the science of identifying or verifying the identification of a person based on unique physical, physiological and behavior characteristics. Physical characteristics include fingerprints, retinal pattern, iris and facial appearance.
Why Biometrics versus Traditional Authentication Methods ?
Biometrics can provide a greater degree of security as these resources are accessible only to authorized users and are kept protected from unauthorized users. Passwords, PINs, Cards and keys are easily guessed, compromised, lost or stolen. Good and long passwords are also too difficult to remember whereas biometrics data cannot be guessed or stolen in the same fashion as a password or card.
One of the reasons passwords or PINs is kept simple, and is subjected to compromise, is that they are easily forgotten. Cards and keys can also be misplaced or lost too. But biometrics is difficult if not impossible to forget and thus offer much convenience than systems based on remembering multiple passwords or on keeping possession of an authentication token.
Given the increased awareness of security issues in enterprise and in customer facing applications, the need for strong ability to trace and reporting capabilities has become more important than ever. This reliable capability of audit trail will enhanced the level of security and accountability.
Fraud Detection and Fraud Deterrence
As biometrics data are unique to every individual, the opportunity of using fraudulent documents, stolen keys, cards and any other access authentication tokens will be totally minimized. In fact, United States is beginning to implement biometrics technologies on individuals in their database for identifying and tracking people to enhance their security.
Among all the biometrics techniques, fingerprint-based identification is the earliest method that has been successfully used in numerous applications. Every individual is known to have unique and immutable fingerprints. A fingerprint is made of a series of ridges and furrows (valleys) on the surface of each finger. The uniqueness of each finger can be determined by the pattern of ridges and furrows as well as minutiae points. Minutiae points are local ridge characteristics that occur at either a ridge bifurcation or ridge ending.
: A fingerprint line raised a ridge
Valley : A groove between the ridges
Ending Point : An end point of the ridge flow
Bifurcation : A bifurcation of the ridge flows
Core : The largest curvature of ridge
Delta : A zone where the ridge splits into three lines and then converges.
What is fingerprint scanning ?
Fingerprint scanning is the acquisition and recognition of a person’s fingerprint characteristics for identification purposes. This allows the recognition of a person through physiological characteristics that verify the identity of an individual.
There are basically 2 major types of finger-scanning technology that make this verification possible.
One is an optical method which starts with an optical image of a finger
The other uses a semiconductor generated field to image a finger
Optical Fingerprint Input
Optical fingerprint type is developed to replace traditional stencil pattern type. Structure of optical fingerprint type is shown on above picture. The light from source is reflected through prism, and image capture device acquires it through the lens. Position and angle of lens have to be accorded for operating optical fingerprint type as shown. It needs separated device to confirm that finger contact on sensor directly. It interprets fingerprints by sensor infrared ray and resistance of human body.
This technology is considered advanced as it helped fingerprint sensor to be small and simple, and so its application area becomes wider. Also, the mass production of semiconductor reduces its manufacturing cost and thus makes it more affordable. Semiconductor fingerprint sensor's structure is very simple as shown in above picture. It gains fingerprint image as it touches the surface of sensor. Semiconductor is divided as follows: stoppage quantity, pressure, sensing of heat by kind of sensor array, and contact type and sliding type by way of finger's contact.
Fingerprint matching techniques can be placed into 2 categories
1. Minutiae-based matching technique
2. Correlation-based matching technique
Minutiae-based method will first find minutiae points and then map their relative placement on the finger. However, there are some difficulties when using this approach. It is difficult to extract the minutiae points accurately when the fingerprint is of low quality. Also this method does not take into account the global pattern of ridges and furrows.
The correlation-based method is able to overcome some of the difficulties of minutiae-based approach. However, it has some of its own shortcomings too. This matching technique requires the precise location of a registration point and is affected by image translation and rotation.