Fingerprint ID
System Basics
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The generic biometric process flow
Enrollment
The first step in the process is called enrollment. Here a new user teaches
the system how to recognize him. In fingerprint systems, the new user
typically places his finger several times on the fingerprint sensor, allowing
the system to memorize his fingerprint.
Authentication
Authentication is the process of certifying a person’s identity by matching
current measurements of his biometric properties with measurements that
were taken and stored during enrollment. In fingerprint systems, the user
places his finger on the sensor and the computer compares the current
fingerprint to the stored fingerprint. If the two patterns are similar enough,
the person’s identity is authenticated.
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The enrollment process
Data
acquisition
Sensor
Sensor
Feature
Extraction
Enrollment
Processor
Processor
Template
Construction
Template
Storage
Storage
Storage
A biometric system has three components: a sensor, a
processor, and data storage.
The sensor is responsible for acquiring biometric data from the
person. The quality and repeatability of this input data sets the
fundamental performance of the system.
During enrollment, the processor analyzes the input data and
extracts the “features” that will be used compute a match during
subsequent authentications.
The processor then formats the extracted features into a
biometric template that is stored for future reference.
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The authentication process
The same (or a similar) set of components are used for Authentication.
The sensor must acquire data that is equivalent to that recorded during
enrollment. The processor may extract the features used for
identification and then compare them to the template retrieved from
storage. Alternatively the template features may be compared directly
to the live input data for a match assessment. If the new data matches
the previously stored template well enough the ID is accepted.
Data
acquisition
Feature
Extraction
Sensor
Sensor
Authentication
Pattern
Matching
Processor
Processor
Storage
Storage
Accept
or Reject
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Template
Storage
The complete biometric process flow
Data
acquisition
Feature
Extraction
Sensor
Sensor
Data
acquisition
Feature
Extraction
Sensor
Sensor
Enrollment
Template
Construction
Processor
Processor
Storage
Storage
Authentication
Pattern
Matching
Processor
Processor
Storage
Storage
Accept
or Reject
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Template
Storage
Applications of Biometrics
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Biometric applications fall into 2 broad classes
z
Unassisted Identification (a.k.a. cold search)
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User provides only the biometric data
The system finds the ID using only the biometric data by searching a biometric
database (often a large database)
Typical Uses
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z
for criminal id checking
security background checks
Government entitlement grants (to prevent double dipping)
Most law enforcement systems use unassisted identification
ID Verification
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User provides a claimed identity and biometric data to verify that claim
The system compares the live biometric data to previously stored data for the
specific claimed identity
Typically used for various kinds of access control
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Physical access (building entry, secured areas, controlled substance cabinets)
Logical access (computer login, database access, etc)
Personal access to digital signature codes
Most commercial systems use ID verification
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Personal Identification Examples
Computers
PDA’s
Physical
Access
Control
Cell
Phones
Automotive
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Comparing Law enforcement systems to
Commercial systems
É
Many commercial fingerprint ID applications are fundamentally different than
classic criminology fingerprint applications
z The operational methods are different
z The failure modes are different
z The specifications and test methods are different
Law enforcement
fingerprint systems
Commercial fingerprint ID
systems
Purpose of system
Determine if subject has a
criminal record, possibly under a
different name (alias)
Determine if user is same
person to whom user privileges
were granted
Input data
Single captured sample (typ. ink
or latent) of finger, not
interactive
Live scan of finger, real time,
interactive with user
Matching target
Large database of possible
templates
One template or small number of
possible templates
Some key features of
system
Fast database indexing and
sorting, data collection under
trained supervision
Low cost, unattended operation,
user-interactive real-time
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Where to go from here
Click here to learn
about Specifying
commercial
biometric systems
Click here to learn
about TruePrint
high-performance
fingerprint imaging
technology
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