Biometrics is a statistical study of biological observations and phenomena, which can be implemented to provide automated methods that can be utilized to identify an individual based on physiological and behavioral characteristics. Examples of features that can be measured include facial variations, fingerprints, hand geometry, handwriting, iris and retinal differences, and voice.
The ability to identify and distinguish among individuals based on specific physical features is grounded in the existence of genetic diversity throughout humankind. The identification of a specific trait that is expressed (known as the phenotype) is possible because each individual possesses a unique genetic makeup (known as the genotypes) that expresses certain physical characteristics that are also unique (e.g., fingerprints and retinal differences).
Those presently benefiting from biometric technologies are enterprise-wide network security infra-structures, government IDs, secure electronic banking, investing and other financial transitions, retail sales, law enforcement, and health and social services.
The history of biometrics dates back to the late 1800s, when Sir Francis Galton (the founder of biometrics and cousin of Charles Darwin) opened the Anthropometric Laboratory at the International Health Exhibition in 1884. Galton’s passion for applying statistical methods to biological phenomena eventually lead him to invent the first system of fingerprints in 1892. This system was adopted by police departments worldwide and is still used today.
For biometric identification systems to be reliable, physical and behavioral features used for recognition must be unique, permanent, measurable, and user-friendly. Uniqueness, biometrically, means that the trait being measured is specific to only one individual and must not appear in two people. If a trait is found in many people, then it is known as “universal” and is not unique. Permanence means that this trait must also not change over time or be able to be physically altered. Measurability means that these specific traits must be able to be consistently measured with technical instruments. The information measured must be able to be effectively stored and compared in a bio-metric reference database so that the identification of an individual can be determined and authenticated.
The use of fingerprinting in individual identification was successful because each person has a unique and immutable fingerprint (including identical twins). Physically, a fingerprint is composed of many series of ridges, splits, dots, valleys, furrows, and “minutiae points.” Minutiae points are specific ridge characteristics that are found on either a ridge bifurcation or a ridge ending. Today, all of the characteristics found on an individual fingerprint can be converted to a “digital fingerprint template” and stored on a central database for subsequent matching or authentication processes. Fingerprinting was the most reliable form of identification in forensics until the development of DNA technology.
Handwriting recognition (or signature recognition) is also used in biometrics. This is more modernly referred to as “dynamic signature verification” (DSV) and analyzes the manner in which a user signs (e.g., velocity and pressure exerted by the individual’s hand, as well as the static shape of the finished signature). Technology used to measure these characteristics ranges from simple scanners, video cameras, and pens that contain sensors to ultrasonic sensing.
Facial recognition and photo identification are another widespread use of biometrics. This type of identification is used worldwide for important matters, such as international passports, and nominal matters, such as purchasing beer. However, facial recognition is not the most accurate form of identification because of similarities that are found in facial structures, especially among relatives. Information on identification cards can also be altered. In addition, physical alterations can be made surgically with relative ease.
Currently, biometric methods measuring voice recognition are being used for personal items such as computers and cellular phones. Voice recognition technologies are also being used in the medical field for quicker retrieval of a physician’s dictation of medical records or office visits. In the past, a typical visit to the doctor’s office was documented on paper by hand or dictated onto a tape recorder and later typed by a medical transcriptionist, which may have taken days to get back. Now, with the new technology of voice recognition, a medical dictation can be spoken into a computer and made available within a few minutes. In the future, voice recognition may eventually replace the use of keys in automobiles.
The iris (the colored region of the eye) and the retina (found in the back of the eye) can be scanned to authenticate individual identification. The iris scan utilizes a special camera with an infrared imager that illuminates the eye and captures a very-high-resolution photograph, which is then matched for verification. This process takes only a few seconds. In addition, contact lenses and eyeglasses present no problems with the quality of the image. The retinal scan analyzes the blood vessels in the back of the eye, which supply nutrients to the photoreceptors (known as rods and cones) of the retina. The scanning utilizes a low-intensity light source and an optical coupler, which reads blood vessel patterns with great accuracy. However, a person must stand still for several seconds to receive an accurate read, and there are concerns that the light source used may cause damage to the eye. In addition, the cost of the technology for retinal scans and its inability to evolve with newer technology have made retinal scan devices impractical for most situations, and it is being replaced with the more user-friendly iris scan. Iris and retinal scans are more widely used in military bases, bank vaults, corporate repositories, airports, and other areas of high security.
In the future, it may be conceivable that “genetic sampling” will replace all other forms of biometric measurements. This is a realistic possibility because the genomic makeup of an individual is the most specific element of our physical being and it is unique above any characteristic presently measured. The idea of genetic sampling will become more of a reality with the completion of the Human Genome Project.
- Ashbourn, J. (2003). Practical biometrics: Fromaspiration to implementation (Springer professional computing). New York: Springer-Verlag.
- Bolle, R. M., Connell, J. H., Pankanti, S., Ratha, N. K., & Senior A. W. (2003). Guide to biometrics. New York: Springer.
- Wayman, J. L., Jain, A. K., Maltoni, D., & Maio, D. (2004). Biometric systems: Technology, design and performance evaluation. New York: Springer.