AFIS Fingerprint Identification And AI Essay Research — страница 2

establishing the identities of criminals reluctant to admit previous arrests. Other personal characteristics change – fingerprints do not. Around 1870 a French anthropologist devised a system to measure and record the dimensions of certain bony parts of the body. These measurements were reduced to a formula which, theoretically, would apply only to one person and would not change during his/her adult life. This Bertillon System, named after its inventor, Alphonse Bertillon, was generally accepted for thirty years. But it never recovered from the events of 1903, when a man named Will West was sentenced to the U.S. Penitentiary at Leavenworth, Kansas. There was already a prisoner at the penitentiary at the time, whose Bertillon measurements were nearly exact, and his name was

William West. Upon an investigation, there were indeed two men. They looked exactly alike, but were allegedly not related. Their names were Will and William West respectively. Their Bertillon measurements were close enough to identify them as the same person. However, a fingerprint comparison quickly and correctly identified them as two different people. The West men were apparently identical twin brothers per indications in later discovered prison records citing correspondence from the same immediate family relatives. Why do people leave fingerprints? The sweat glands in the skin of the fingertips produce a water based oil solution that coats the ridges of the print. These ridges retain a portion of this solution such that when the finger makes contact with a surface, a residue

is left behind which is a facsimile of the print (i.e., latent print). It is this characteristic which gives the biometric devices the ability to electronically scan and analyze a given print. Common Types of Fingerprints: 1. ROD. A Rod generally forms a straight line. It has little to no curved features and tends to be found in the center of the fingerprint’s pattern area. 2. ELLIPSE. An Ellipse is a circular or oval shaped line-type, which is generally found in the center of Whorl patterns. 3. SPIRAL. A Spiral line-type spirals out from the center of the fingerprint and is generally found in whorl print patterns. 4. BIFURCATION. Is the intersection of two or more line-types, which converge or diverge. 5. TENTED ARCH. Resembles a tent. This line-type quickly rises and falls at

a steep angle. They tend to be associated with Tented Arch pattern prints. 6. ISLAND. An Island is a line-type, which stands alone. (i.e., does not touch another line-type and is totally contained in the pattern area of interest). 7. SWEAT GLAND. The finger contains many sweat glands. The moisture and oils they produce actually allow the fingerprint to be electronically imaged. 8. ARCH. Arch line-types can be found in most print patterns. Fingerprints made up primarily of arches are sometimes classified as Arch prints. 9. MINUTIAE POINTS. Is the term used to define common micro features in a fingerprint. Common minutiae points are the intersection of bifurcation, ending points of Islands and the center point of the sweat glands Fingerprints are classified in a three-way process:

by the shapes and contours of individual patterns, by noting the finger positions of the pattern types, and by relative size, determined by counting the ridges in loops and by tracing the ridges in whorls. The information obtained in this way is incorporated in a concise formula, which is known as the individuals fingerprint classification. There are several variants of the Henry system, but that used by the Federal Bureau of Investigation (FBI) in the United States recognizes eight different types of patterns: radial loop, ulnar loop, double loop, central pocket loop, plain arch, tented arch, plain whorl, and accidental. Whorls are usually circular or spiral in shape. Arches have a mound-like contour, while tented arches have a spike-like or steeple-like appearance in the

center. Loops have concentric hairpin or staple-shaped ridges and are described as “radial” or “ulnar” to denote their slopes; ulnar loops slope toward the little finger side of the hand, radial loops toward the thumb. Loops constitute about 65 percent of the total fingerprint patterns; whorls make up about 30 percent, and arches and tented arches together account for the other 5 percent. The most common pattern is the ulnar loop. Automated Fingerprint Identification System (AFIS) – is an algorithmic software for fingerprint search matching and fingerprint recognition. It uses the FBI/Yale/Los Alamos [W]avelet-packet [S]calar [Q]uantization fingerprint compression algorithm (WSQ). Which is the standard compression algorithm for scanned fingerprint images. It preserves