Overview of the Biometrics System
Advantages of RF Logics' Fingerprint Biometric
The company's Fingerprint Biometric Readers have been designed specifically
for use in the security and access control environment. Over 60,000
of these devices have been sold world wide, and their performance in
the harsh environment of both military and commercial applications has
The Fingerprint Biometric products utilize an Optical Scanning technique
using Surface Enhanced Irregular Reflection Technology (SEIR), with
High Contrast, Uniform Intensity Imaging. This technology combined with
the company's own sophisticated, state-of-the-art algorithm for comparing
fingerprint images, delivers a uniquely robust and accurate performance
from a range of readers which can be used either as part of a wide range
of access control and time and attendance systems or as stand alone
devices with their own door programming and control capabilities.
The readers are designed to withstand daily use in testing environments
and may be mounted outdoors. They are not susceptible to static discharge
or other external conditions, which commonly cause problems with other
types of biometric reader systems.
The SEIR technology allows the use of a Sapphire Crystal finger-reading
surface, which is highly resistant to scratching and damage, requiring
little or no maintenance. Combined with the polycarbonate housings,
the products while architecturally pleasing are extremely robust and
operate in the most testing environments.
The Fingerprint Biometric readers are available in combination with
RF Logics' own proximity card reading systems; they may be used with
card readers of other manufacturers; with RF Logics' MIFARE contactless
smart cards, carrying the finger template on the card; with PIN code
identification or as direct fingerprint comparison readers.
Need for Biometrics
Security and Management
The biometrics market arose from the need to prevent any risks or damages
in various fields and it uses identity authentication to answer that
need. Its uses range from physical control and management including
entrance control, diligence management, and machine access control to
security and management in the information industry, including computer
security, distance education, e-commerce, information security, and
so on. These days, computer processing of so much important information
fosters information exchange in the cyberspace, and expands e-commerce
fields to include online banking. Against this backdrop, the demand
for valid identity authentication is soaring along with the growth of
the related businesses.
Convenience is one of the greatest advantages of biometrics compared
to existing methods of personal authentication such as keys, identification
numbers (ID) and passwords. In other words, everyone can be uniquely
identified without the need for an ID, a magnetic card, a smart card,
a key or a personal identification number (PIN). A user can verify each
individual by using only physical traits such as fingerprints and voice.
Also, using biometrics, a machine can electronically recognize a user,
thereby enabling its system to allow for the automatic response to that
user's request. In short, biometrics is able to deliver both safety
and convenience in the identity verification field, thereby reaping
huge economic benefits.
Characteristics Needed by Biometric Systems
A biometrics system should use personal traits
developed with the following "ideal" criteria: universal (everyone has
it), unique (no two people have it alike), permanent (does not change
and cannot be changed), collectable (easy to obtain and quantify with
Concerns during the system design should include Performance (precision,
speed, tenacity, resource request, operational/environmental components),
Acceptability (the degree of acceptance by people), and Circumvention
(how easy it is to outsmart the system). The traits also become a yardstick
for the system evaluation.
All biometric technologies invariably have their own advantages and
disadvantages. Table 1-1 shows the characteristics index of various
kinds of biometric technologies.
1.1 Index of Biometrics Types
Types of Biometrics
Biometrics using Physical Characteristics
Fingerprints, face, iris, vein, cornea, hand, DNA pattern, ear, etc
- Relatively stable
- Does not change much in a lifetime
- Huge, expensive equipment needed. Intrusive method
Biometrics using Behavioral Traits
- Signature, voice recognition, walking style
- Change according to psychological condition
- Influenced by physical traits (men/women, build)
- Change a lot
- Simple, inexpensive equipment. Non-.offensive method
Figure 1.1 Fingerprint Enrollment and Authentication
Processes in a General Fingerprint Recognition System
Figure 1.1 is a concept map to show
the process of fingerprint enrollment and authentication in the system.
All biometrics systems identify an individual according to the process.
The first step in the biometrics system application is the enrollment
of a user in the system.
The registered biological information
is raw data. By processing the data with signal algorithms such as
image process, feature data to represent vital information of that
individual can be obtained. The feature data will play the role of
the Template. Storing the Template in a database finishes the user
enrollment process. After enrollment, the user should provide his
or her bio-information such as fingerprints or facial planes to use
the system. The biometrics system processes the information and gets
his or her feature data and compares the data with the Template, thereby
calculating similarity or matching score. After that, it matches the
score with the critical value set in the initial setting to finally
verify the identity. Figure 1.2 shows the biometrics system in logical
Figure 1.2 Biometrics System Logical Blocks
Identify an Individual with the Biometrics System
By providing a user's ID and bio-information to the system at the
same time, the user activates the system to compare his or her feature
data obtained from the entered bio-information with the stored Template
of the corresponding ID. This process of 1:1 matching is called verification
is being applied to various business areas such as access control
and payment authentication where a PIN is needed. For example, this
can be used for a door-lock so that a user enters his or her ID and
has the door reading the fingerprint. Or it can also be used for PC
user provides his or her bio-information only to the system. Next,
the system matches the information with a Template with the highest
similarity, and finds the enrollment information of that user. This
is the 1:N matching process called identification or recognition.
It is being used for AFIS (Automatic Fingerprint Identification System)
to find a criminal's identity through fingerprints on the crime scene.
Or a camera uses the face recognition technology to find a wanted
man in a crowd.
The most striking difference between the biometrics system and a traditional
authentication system based on an ID/password is that the new system
cannot generate 100 percent 'Yes' or 'No' answers. On the other hand,
other existing systems can do so according to letters or numbers entered.
In the case of biometrics, biological information could change in
terms of its shape or angle when it is read, so matching scores against
Templates could change accordingly.
As a result, even a valid person
may be rejected or a wrong person may be accepted. The ratios developed
to evaluate the probabilities of the two cases are called FRR (False
Rejection Ratio) and FAR (False Acceptance Ratio).
Figure 1.3 Concept Map on FRR & FAR
In Figure 1.3 shown above, the shaded
portion with oblique lines on the left part of a critical value is
FRR, and the other portion on the right part, is FAR. Certainly, a
system with less shaded portion is better.
Figure 1.4 Changes in FRR and FAR according to
changes in the critical value
The above Figure 1.4 shows the change
patterns of FAR and FRR according to changes in the critical value.
The point where FAR and FRR are the same is called EER (Equal Error
Rate), and is used as a yardstick for evaluating the system's performance
along with the two other ratios.
The smaller the shaded portion in
Figure 1.3 is, the closer the graph in Figure 1.4 will be to the X
and Y axis. A user can set a different critical value according to
his or her purposes. For example, in the case of a very important
security system, the user can reduce the possibility that an unauthorized
person is accepted to near zero by setting a critical value high enough.
Instead, even an authorized person can fail to get access at times.
On the other hand, if police is looking for a criminal with fingerprints
obtained from the crime scene, it will be necessary to search for
and analyze all possible fingerprints. In areas such as these, it
is useful to set the critical value low enough to find all possible
matches in the fingerprint database. In short, the higher the critical
value is, the less convenient the system can be but, at the same time,
its security is higher. Conversely, the lower the value is, the more
convenient the system is, but its security is lax. Therefore, it is
very important for a user to set an appropriate critical value according
to needs or areas of application.