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Fingerprint Comparison

From digital files come ten prints, the set of ten fingerprints recorded by law enforcement agencies. (The ridges on ten prints are well defined).

From the crime scene comes a latent fingerprint. (This fingerprint is lacking in detail and in general is not very clear).

The important capability of matching fingerprints found at the scene of the crime to those on record has been plagued with problems of organization, manpower, and distance.

Federal Bureau of Investigation

Using new computer technologies, the FBI has developed the Universal Latent Workstation.

Universal Latent Work Station

This software makes it possible to scan digitized fingerprints to find small details called minutiae. After finding the minutiae, the software program then compares the details from the latent fingerprint with a database containing sets of ten prints to determine possible matches.

 


 

Minutiae

Minutiae is the term used to describe recognizable details on a fingerprint.

Details are marked, by the software, on the digitized image of the fingerprint.

A circle represents a minutia termed a ridge ending.

A bifurcation is a ridge that splits into two ridges and is symbolized with a square.

A line, termed a tail, is added to the minutia symbol to indicate the direction of the ridge. In the case of a ridge ending or bifurcation, the tail begins near the middle of the symbol and extends outside the circle or the square about 2 times the width of the symbol.

A delta is a location where ridges form a "Y" and is indicated by a circle with a "V" peaking at the center of the circle. The sides of the "V" reach to the edge of the circle. There is a short tail also reaching from the point of the "V" to the circle to indicate the direction.

A site where the ridges make a U-turn is called a core. A circle with a small square in the center and a tail reaching from a corner of the square to the edge of the circle symbolizes the core.


 

After locating the minutiae on a latent fingerprint, a search can be made of sets of ten prints that have been archived. Matching prints are then turned over to the latent fingerprint examiner.

ITL and NIST have contributed to this project in three ways:

  1. First, this FBI tool is operating in a Data Interchange Format, an ANSI-NIST standard.

    ITL also provided two public domain software technologies:

  2. Image enhancement
  3. Minutiae detection

These contributions are a key to the overall success of this program.

Since 1967, NIST has been working with the FBI in areas of fingerprint processing and law enforcement standards. The Universal Latent Workstation is just a small example of ITL's continuing support of these efforts.



For more information contact: Micheal Garris

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