Understanding Biometric Systems: A Comprehensive Guide

A biometric system is a technological solution that utilizes unique physical, physiological, or behavioral characteristics of individuals to identify and authenticate them.

Biometric systems are employed for various purposes, primarily for security and access control applications. The technology utilizes the following characteristics in order to authenticate or identify a valid individual:

• Fingerprints
• Voiceprints
• Facial features
• Writing patterns
• Iris patterns
• Hand Geometry
• etc.

Biometric systems rely on characteristics that are inherently unique to each individual, unlike traditional methods of identification like passwords or PINs, which can be forgotten, stolen, or shared.

How Biometric Systems Work

Biometric systems typically work by capturing an individual’s biometric data through fingerprint sensors or cameras. The captured data is converted into a digital format and then compared with pre-stored templates or data in a database. If the captured data matches an existing record, the individual is authenticated or granted access.

Figure 1: Biometric System Block Diagram

The figure above depicts a block diagram of a biometric system. It consists of the following biometric processes:

• Data Collection: The main component is a sensor that captures the image of the pattern. This image is then compressed.
• Transmission: The compressed image of the pattern is transmitted and stored.
• Signal Processing: A live pattern sample is collected, and unique features are extracted using signal processing algorithms. This is then compared with the unique features of the image initially stored at the time of enrollment.
• Data Storage: This is the storage location for the image samples of many people. This can be a hard disk or any other memory type.
• Decision: This is a software, hardware, or a combination of both, which compares the live data with the one stored in the database for authentication and verification purposes.

Figure 2: Biometric Identification Process

The diagram above depicts a biometric process flow chart. Let’s understand how it works with the example of fingerprint scanning. As shown, hardware such as a finger scanner captures salient human finger data. The software interprets the resulting data and determines its acceptability.

Fingerprint Recognition

Fingerprint recognition is the oldest method of biometrics. It is highly reliable and uses distinctive features of fingers. A fingerprint image is read from a capture device such as a finger scanner. These features are extracted from the image, and a template is created for comparison.

Figure 3: Finger Patterns

The following global and local features of a finger help in fingerprint recognition:

• Global features: Pattern Area, Core Point, Delta, Line Types, Ridge Count, Ridge Patterns
• Local features: ARCH, LOOP, WHORL

The figure above depicts the finger patterns as mentioned above. There are three stages in this process: fingerprint scanning, fingerprint matching, and identification. In this type of biometric identification process, acquisition and recognition of a person’s fingerprint characteristics are used. There are various methods of image capture such as optical, thermal, capacitive, ultrasound etc.

Advantages of Biometric Technology

The advantages of biometric technology include:

• No need to remember passwords or PIN numbers when using applications based on this technology.
• Provides the highest level of security.
• It is a highly reliable technology.
• Used in a wide variety of applications such as criminal identification, prison security, credit card security, biometric door locks, weapon activation, ATM, aviation security, border crossing controls, database access, etc.

Disadvantages of Biometric Technology

The disadvantages of biometric technology, especially with fingerprint identification or similar image processing technology, include:

• Needs very careful enrollment.
• Has a high false reject rate due to pressing too hard, scarring, misalignment, or dirt present on the fingerprint scanner device.
• Vendor incompatibility in following accurate biometric technology processes.
• Various cultural issues, e.g., physical contact requirement a negative in Japan, privacy issues in North America.
• Presenting fake image patterns to the sensing devices.

Conclusion

This Biometric tutorial is useful for beginners as well as advanced enthusiasts in the field of Biometrics.