A Review of the Present and
Future Biometric Technologies
Chapter 2 will now take a part of Chapter 1 and explore it in much more
exhaustive detail, that is, biometric technologies that are available today.
Each biometric technology that was presented in Chapter 1 will now be
further expanded upon and reviewed.
Before we move onto our detailed discussion and analyses of the bio-
metric technologies that are available on the market place today, it is very
important to turn back to the topic of physical biometrics and behavioral
biometrics. As was mentioned in Chapter 1, physical biometrics involves
taking a biological or physiological snapshot of a part of our body and
behavioral biometrics involves taking a picture of our unique manner-
isms that make us different from everybody else.
However, we need to provide much more precise, scientic deni-
tions to these two terms. Physical biometrics can be dened as “acquir-
ing physical biometric samples which involves taking a measurement
from subjects. This does not require any specic action by the subject. A
physical biometric is based primarily upon an anatomical or physiological
characteristic rather than a learned behavior” (Certied Biometrics Learning
System, Module 2, Biometrics Standards, © 2010 IEEE, p. 2–1).
Behavioral biometrics can be dened as “Acquiring behavioral bio-
metric samples requires subjects to be active. They must perform a specic
activity in the presence of a sensor. A behavioral trait is learned and
acquired over time rather than based upon biology” (Certied Biometrics
Learning System, Module 2, Biometrics Standards, © 2010 IEEE, p. 21).
As one can see, based upon these two denitions, some very subtle dif-
ferences between physical biometrics and behavioral biometrics can be
observed. Probably the biggest difference to be noted is the amount of
activity required by the end user. With physical biometrics, no active part
is needed on the part of the individual in order to collect that individual’s
physiological and biological unique features (whether it be the hand, the
nger, the iris or retina, or even the vein patterns present from under-
neath the palm or the ngerprint). The end user must be cooperative in
order for an effective sample to be captured (this is true for all biometric
In other words, physical biometrics can be more or less considered
as garbage ingarbage out. The image is captured, unique features are
extracted, and the individual is either veried or not. However, with
behavioral biometrics, a specic function, or an active part, must be car-
ried out (such as typing on a keyboard or signing your name), which is
learned over time.
As a result, because of this learned behavior, deviations or changes
in the behavioral-based biometric templates that are collected can drasti-
cally occur over time, at a level much more so than physical-based bio-
metric templates. Hence, research and development is already underway
in which a behavioral-based biometric system can literally learn and take
into account such changes in the behavior and mannerisms that can occur
over the lifetime of an individual.
A perfect example of this would be the use of neural network technol-
ogy. With this type of technology, computer-based learning and reason-
ing takes place in an attempt to closely follow the actions and patterns of
the human brain.
Another difference between physical biometrics and behavioral
biometrics that is evident from the above denitions is the number of
measurements taken to extract the unique features. In both types of tech-
nologies, multiple images or multiple samples are collected. However, in
physical biometrics, only one composite image is utilized from which to

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