|  | Public Health Safety | Community

How Do Scientists Identify the Different Types of Fingerprints?

We are born with the same unique fingerprints we have now and will have until we die. When a person is fingerprinted, the prints are stored in a database. Out of the vast numbers of fingerprints on record, how do scientists identify the owner of a particular set of prints? The methods they use vary, but are all based on the premise that all fingerprints are one-of-a-kind and that they are permanent.

  1. Levels of Identification

    • Level 1, the most basic level of identification, categorizes the patterns of loops, arches and whorls. This level is used to rule out a suspect if her fingerprints have a different pattern than those found at the crime scene. Level 2 examines formations and ridge characteristics sufficient to identify a person's fingerprint. Level 3 assesses all of the dimensional aspects of a fingerprint's ridges, such as path divergences, ridge width and shape, and is comprehensive enough to provide unquestionable identification of a fingerprint.

    Minutiae-Based Method

    • Minutiae are local individual ridge characteristics usually found where a ridge forks in two or ends entirely. The Automated Fingerprint Identification System, or AFIS, is a computerized system that searches through thousands of fingerprints in its database and matches those with certain minutiae specific to the search. The scientist will then peruse the possible matches the computer has provided to narrow the search. One limitation to this method is that it is not effective when the fingerprint is of poor quality.

    Correlation-Based Method

    • The correlation-based technique works by locating a precise registration point in the fingerprint in question. The system chooses a template that corresponds to the first fingerprint, then another template corresponding to the second fingerprint, and it transposes one over the other. With this method, even prints of poor quality can be evaluated accurately.

    Fingerprint Databases

    • The Automated Fingerprint Identification System database contains fingerprints from across the United States and other countries. Using this database, scientists can search through large numbers of fingerprints in mere seconds, to identify criminals and perform background checks.

Community - Related Articles