What Lies Under The Magnifying Glass?
The Basics of Fingerprint Analysis
Have you ever watched a detective movie or TV show? When examining a crime scene, what’s the first thing that they look for, often with a magnifying glass?
You probably guessed it…fingerprints!
Fingerprints are a form of biometric identification, meaning that they are a biological feature that can be used to authenticate the identity of a person. Today, I’ll be discussing the inner workings of fingerprint analysis!
To learn more about the field of biometrics as a whole, check out my article!
So, why Fingerprints?
Every single person has a unique fingerprint — even identical twins who share the same DNA. As a result of this uniqueness, fingerprints serve as a favorable biometric identifier.
There are a few downsides to using fingerprints as a form of biometric identification. The major concern is that a person will become unidentifiable if their fingerprint becomes damaged, which could be a result of a burn or other things.
Despite this fact, many people consider fingerprint to be one of the safest and most widely known forms of biometrics.
How Does Fingerprint Analysis Work?
Fingerprint analysis can be conducted by hand or with a scanner. But, before I explain how the technology works, you first need to understand the different parts of a fingerprint.
Differentiating Factors of Fingerprints
Fingerprints are generally labeled by their friction ridge, the most common of which are loops, whorls, and arches. Friction ridges are the raised portion of skin that gives it its characteristic grip.
Loops: A fingerprint that recurves in the other direction once it reaches a certain point. These are the most common type of friction ridges in a fingerprint, accounting for nearly 60%.
Whorls: These are circular patterns, that create a whirlpool-looking effect. There are multiple types of whorl patterns, but the most common are plain ones, which comprise of concentric circles. These are approximately 35% of all fingerprints.
Arches: These types of friction ridges look like waves. Arches can either be plain, meaning that they are relatively flat, or tented, which means that they rise to a steeper point. These account for approximately 5% of fingerprints.
Fingerprints are also differentiated by minutiae, including deltas, ridge endings, forks, and lakes.
- Delta: A triangle shape on a fingerprint that is located at an area closest to the point of divergence
- Ridge Ending: The point where one ridge, the lines that are inked on a fingerprint, abruptly ends.
- Forks: One ridge splits off into two separate ridges. This is also often called a bifurcation.
- Lake: Created when a ridge splits into two separate ridges but shortly rejoins back into one ridge.
Fingerprint Analysis — By Hand
I recently conducted my own fingerprint analysis at home to get a hands-on understanding of fingerprint recognition.
I collected fingerprint samples from myself, my parents, and my sister on individual sheets of paper. After I identified the friction ridge type of each fingerprint, I used a magnifying glass to locate seventeen minutiae points on each print and color code the prints.
- Deltas: Blue
- Forks: Green
- Ridge Endings: Red
- Lakes: Purple
After I collected and analyzed all of the original samples, I had my family give me another fingerprint. But this time, I did not know who the print belonged to.
After analyzing the unknown fingerprint in the same process as before, I was able to accurately surmise who the mystery print belonged to, by looking at the ridge patterns and minutiae.
With sample fingerprints in my “database,” I was able to accurately identify a person based on their fingerprint.
Fingerprint Analysis — By Scanner
Not all fingerprint analysis needs to be conducted by hand. Fingerprint scanners are often used for biometric fingerprint recognition. These scanners are electronic systems that are used to verify the identity of people and then let them proceed with a task or transaction.
Fingerprint scanners capture the ridge pattern of a fingerprint and the software of the system is then used to compare it to a stored fingerprint in a database.
If the fingerprint matches that of the one in the database, then the identity has been verified and a green light will be given to proceed with the action.
There are multiple types of common fingerprint sensors including:
Optical Sensors: These sensors work by making a photocopy of the fingerprint. These types of sensors require clear, crisp lines to correctly match the prints, so an extra light source is often used. Most scanners connected to a personal computer are optical.
Capacitive Sensors: These sensors use electricity to confirm the identity of a person, by creating a map of charges. When a finger is placed on the scanner, a ridge will exhibit a charge, while a valley exhibits only a negligible one. Smartphone scanners are often capacitive.
Ultrasonic Sensors: These sensors send out ultrasonic pulses and measure the amount of data that bounces back, which is used to create a 3D map of the fingerprint. The ridge and valley areas of a fingerprint will reflect the sound in different ways. These are currently in development.
Fingerprints are a form of biometric identification, but they are one of the most widely used types. Many people have heard of forensic sciences or used Touch ID on their phones before, so they have used this type of biometric authentification.
The technology surrounding fingerprint recognition is only going to improve with time, as companies like Qualcomm continue to develop ultrasonic sensors. With better technology comes increased use case scenarios, so the use for this form of biometrics could expand rapidly in the next few years.
Key Takeaways
- Fingerprints can be differentiated by their friction ridge pattern types and minutiae.
- Minutiae include deltas, forks, ridge endings, and lakes, all of which can be found on an individual fingerprint.
- Fingerprint analysis can either be conducted by hand — like my replicate project — or with a scanner.
- There are three types of common fingerprint scanners: optical, capacitive, and ultrasonic. They all authenticate identity in different ways.
Thank you so much for reading my article! My name is Nikitha Ambatipudi and I am a 10th-grade student from Glendale, CA. I am an Innovator at The Knowledge Society and I am currently exploring the field of biometrics. Please contact me on LinkedIn or at nikitha.ambatipudi@gmail.com!
