Fingerprints are unique patterns of ridges and valleys on the skin of our fingers. These ridges and valleys are formed when the skin on our fingers is still developing in the womb. They are determined by our genetics and are not affected by our environment. That means that our fingerprints are unique to us and remain the same throughout our lives.
Fingerprint Identification
Fingerprint identification is the process of comparing fingerprints to identify a person. This process is based on the fact that no two fingerprints are exactly alike. Even identical twins have different fingerprints.
There are three main types of fingerprint patterns:
- Loops
- Arches
- Whorls
The pattern of a fingerprint is determined by the way the ridges and valleys are arranged on the skin. Loops are the most common type of fingerprint, followed by whorls and arches.
Fingerprint identification is a very accurate way to identify a person. In fact, it is so accurate that it is often used to solve crimes. When a person is arrested, their fingerprints are usually taken and compared to fingerprints on file in a database. If there is a match, the person can be identified.
Fingerprint identification involves comparing the unique patterns of ridges and valleys on fingerprints to determine whether two prints come from the same individual. Each fingerprint has three distinctive characteristics:
- Ridge patterns: The overall pattern of ridges and valleys in a fingerprint.
- Ridge characteristics: The specific features of ridges and valleys, such as their shape, size, and number.
- Pore patterns: The patterns of sweat pores on ridges.
Types of Fingerprint Analysis
There are two primary methods of capturing and analyzing fingerprints:
- Ink and paper: In the traditional method of fingerprinting, ink is applied to a person’s fingertip, and the individual places their inked fingertip on paper to record their fingerprint impression.
- Digital/Live scan: In the more technologically advanced live-scan method, a fingerprint scanner electronically captures a fingerprint pattern and converts the image into a digital file.
How Automated Fingerprint Identification Systems (AFIS) Work
Modern fingerprint identification relies heavily on automated fingerprint identification systems (AFIS). AFIS allows experts to record, store, compare, and retrieve fingerprint images electronically within seconds.
- After converting a fingerprint pattern into a digital file, the software then calculates minutiae points that represent unique landmarks on the fingerprint. These points allow the software to generate a classification of the fingerprint based on its general pattern.
- Next, the software encodes fingerprint data into a numeric format. This standardized form of the fingerprint is what the AFIS uses to perform rapid matching.
- Then the AFIS compares the encoded input against other fingerprints in the database to find potential matches.
- When a match is found between two encoded fingerprint records, the AFIS displays the images side by side so a trained expert can visually confirm whether they belong to the same individual.
The FBI is the primary contributor to the nation’s fingerprint database. Their Integrated Automated Fingerprint Identification System (IAFIS) contains tens of millions of criminal fingerprint records. IAFIS allows law enforcement agencies across the country to quickly identify suspects and link them to previously recorded crimes.
