Where there are no witnesses to a certain crime, fingerprints can be very useful in determining the offenders and later, during the trial, in proving that they were present at the crime scene. The pores on the skin constantly release perspiration which is made of water, salt, oils, and other substances produced by the body. When skin comes in contact with a surface, these substances are transferred to the surface touched. The impressions left on the surface are called latent fingerprints, and caused by the ridges on the skin. In most cases, they are incomplete and degraded.
Fingerprints are unique.
The differences between fingerprints are due to the type and the position of the ridge characteristics. The individual features that uniquely identify a fingerprint are called minutiae which can be described as various ridge pattern deviations. On the other hand, fingerprints can be classified according to their patterns, such as loop, central pocket loop, plain arch, tented arch, and plain whorl. Thus, the basic ridge pattern together with the minutiae and their locations on the fingerprint pattern uniquely identify a fingerprint. Enhancement has to be performed in order to eliminate the noise and to extract the prominent features in the fingerprint.