Biometric Scanner | 4 mins read

How Does a Biometric Scanner Work?

how does a biometric scanner work
Michelle Jaco

By Michelle Jaco

In today's modern, digital society, it's becoming increasingly common to see biometric scanners in public, in the workplace, and even in the home. And while it's well-known that these devices are more secure than traditional PINs or passwords, many are left wondering how biometric scanners work, and why they are so much more secure than other, more traditional security measures.

This is because biometric data, which consists of a simple retinal or fingerprint scan, can easily verify an individual's personal information quickly and accurately, providing improved, more secure access controls, especially when compared to traditional PINS or passwords.

However, while fingerprint scanning and biometrics technology are becoming increasingly popular, many are still left wondering how biometric systems work.

How it Works

In the past, taking and matching biometric authentication was a much more hands-on process, with the optical fingerprint being taken by dipping a person's fingertip in ink, and then rolling it onto a piece of paper to create an exact match.

However, when a biometric scan is used to control computer or location access, the process of a print scanner is automated by a computer or device, controlled by a complex algorithm, which can either grant or deny access based on the scan of a single finger.

A fingerprint scan is typically taken in one of two ways-

  1. Optical scanning- Optical scanners work by shining a light against a person's fingertips, automatically analyzing the image, and essentially, taking a digital photograph of the fingerprint. For this, these devices use a light-sensitive computer chip to create a digital image of the print and in turn, this image is analyzed by the device's software to be translated into code.
  2. Capacitive scanning- Although similar, a capacitive scanner creates an image by measuring the distances between the ridges of an individual's fingerprint, using these measurements to create its own image and code for the scan.

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Database Creation

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Essentially, for a biometric scanner to be accurate, it needs to be able to match its scans against this database of pre-recorded scans. This means that to use a biometric scanning system, users will first need to create a record of all those who will be authorized to access the computer system or location.


This is most often referred to as the enrollment process.

For example, a business must first take and store the scans of an employee's fingerprints in order to grant them access to the system or location. Then, when an employee wants to sign in or gain access to the network, the fingerprint scanner or biometric authentication system will compare their fingerprint against those in its database.

Biometrics Verification

Once a database of records has been created, the next step is known as the verification process.
For this, the biometric scanner will take fingerprint scans of the individual wishing to access the system, and compare them, in real-time, to see if there's a match in its existing records. Many modern, high-speed biometric scanners are able to process and compare as many as 40,000 scans per second.

If an accurate match is found, then the software will grant access to the person who was scanned.
If there is no match, the scanner will deny the individual access, prompting them to take a new scan.

This is also practical inside the workplace, as employers can implement these practices into their timekeeping systems. By incorporating biometic systems into employee time clocks, the process of payroll accuracy and decrease in time theft improves.

What Occurs During a Biometric Scan

During the creation of the database, or enrollment process, when a person's fingerprints are scanned by the computer, the scan is analyzed for very small features, which are called minutiae.

Essentially, these are the points and locations where the ridges in your fingerprints split apart or end. When scanned, the device's biometric technology will measure both the distance and angle of these minute features, and then uses this information to create a 100% unique computer code.

During the enrollment process, each individual's unique fingerprint code is stored in the database. So for a biometric scanner, this makes granting/denying access as easy as comparing a new scan, or code, to the scans/codes in the database.

Generally, this process only takes a few seconds and is considerably more accurate than other methods of matching fingerprints since everything is automated by a computer algorithm.

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Why Biometrics Are So Unique

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When it comes to biometric features, such as our fingerprints, the age-old saying couldn't be any truer that no two people are exactly alike. In fact, no two persons in all of human history have the same pattern of lines and ridges on their fingertips.

In fact, while a person is still in the womb, their fingerprints are developing through a completely random process governed by their unique genetic code, or DNA. Because of this random development process, even identical twins don't have matching fingerprints.

In the end, this means that a fingerprint reader can be a simple, and extremely accurate, method of controlling access to locations, devices, or computer networks.

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