Fingerprint

The fingerprint (or Daktylogramm ) is an impression of the friction ridges on the end member of a finger ( finger tip or finger tip ). Given that no two people with the same fingerprint are known, it is based on the uniqueness of fingerprint. In very rare cases, the fingers are missing due to a genetic defect, the ridges and thus leave no marks ( Adermatoglyphie ).

Minutiae

As minutiae ( minutiae lat = " trifles" ), the endings and bifurcations of the human fingerprint ridges are called. Because the minutiae as the result of a random process only emerge during the growth of the fingers, even identical twins have different fingerprints. This process is not complete until the end of childhood. Exception, caused by a few anomalies and no fingerprint.

There are different features of the fingerprint:

• Basic pattern
• Coarse features: loops, arches, turns
• Finer features: minutia
• Pore structure

Criminology

In the field of criminology fingerprints found at the scene of a suspect are compared with a database to identify the suspect. The German Federal Criminal Police Office performs an AFIS database containing the fingerprints of over three million people. The comparison of fingerprints with large amounts of data was made possible by the advent of powerful computers and accurate mathematical descriptions of the properties of a fingerprint.

As the inventor of the identification of people by fingerprints, the English scientist Francis Galton and the Argentine Criminologist Juan Vucetich apply. The security of fingerprints with the help of the so-called " paint film method" goes back to the geologists Ehrhard Voigt, who invented it in 1930 in order to conserve soil and sediment profiles.

The use of fingerprints in forensics is controversial to some extent. Since fingerprints (biology, anthropology ) not found in any natural science a direct application, the use of fingerprints has been monopolized by the early criminology. Therefore, the question is justified whether the comparison of fingerprints withstand scientific criteria. Compared to DNA profiles or trace analysis with gas chromatography equipment, where the probability of a false conclusion is known, there is the reliability of fingerprint comparing only a few studies. It became known erroneous assignments of fingerprints. This is attributed to methodological shortcomings, such as a vicious circle of characteristics of the reference impression on the crime scene fingerprint.

Since 1923 there are in the U.S. so-called " Frye standard ", it is checked with which scientific reasoning are inadmissible in court. According to Frye, a method (such as forensics ) must be " generally accepted " only in the relevant art, which, for example, the use of polygraph results enabled in criminal proceedings.

In the process of Daubert vs.. Merrell Dow Pharmaceuticals ( 1993) before the U.S. Supreme Court of the Frye standard, however, was felt to be inadequate and replaced by the so-called " Daubert standard ". This requires not only the recognition in the subject area, but among other things, a well-established knowledge of how high the error rate of the procedure in question. The proportion of false-positive results in fingerprint comparisons will be most important in this regard. As the Daubert standard is implemented by the courts, is of importance for the fingerprint as evidence.

Other applications

(-: Simplified system for control of aids to return German Outil simplifié de contrôle des aides au retour ) by a decree of October 26, 2009 set up a database in which the names of persons to be performed in France, the system was Oscar within the framework of organized deportations amounts of aide au retour have received humanitaire ( ARH). From September 2010, fingerprints are out there in addition.

Biometrics

Manufacturer of biometric systems set the fingerprint (eg capacitive) is read mostly optically or electrically, also for identification to distinguish authorized from unauthorized users. To deny access when imitated fingerprints, temperature and pulse sensors can be integrated into the detection devices that check whether a living finger was placed on the device ( " liveness detection " ), which is visible only limited effect. Since the detection of the fingerprint is reminiscent of an official act, this system, however, is not popular with all users, so often alternative biometric recognition systems are used.

To extract the minutiae, a special algorithm is used by which the minutiae are brought into a mathematical form. From the picture provided by the fingerprint scanner -specific data are collected for each fingerprint. A specific fingerprint no longer be reconstructed from the minutia.

The security of fingerprint systems is relatively small as a fingerprint is easy to imitate.

For authentication, multiple minutiae with existing reference data are compared. With the biometric fingerprint method ( fingerprinting ) fingerprints are compared, to identify individuals clearly can.

Animal kingdom

Koalas are one of the few non-primate whose fingertips have ridges that are extremely similar to those of humans.

Others

The word " fingerprint" is also used metaphorically or figuratively, to highlight unique characteristics of a person or thing. Thus, for example, speaks of the " genetic fingerprint" or the " digital fingerprint " in the electronic signature or checksum electronic messages. Chemical substances have in the IR spectrum to a region which is substance specific fingerprint region is called.

A new trend is to make fingerprints visible on electrochemiluminescence. Scientists used this coated with indium tin oxide glass plate or a plate made ​​of stainless steel as an electrode. On the fingerprint is applied and a solution with the reactants ( a ruthenium complex with a reactant, typically tripropylamine, reacts ) was added. Where the fat-containing components of the fingerprint adhere, the electrode is inactive, the electrochemical reaction can not occur and the lamp is prevented. In the other areas of the electrode is active and there is a negative image of the fingerprint, which can be recorded with a CCD camera. In one variant, fingerprints can be represented as a positive image. For this, the fingerprints are first treated with a reagent that binds to the components of the fingerprint. After application of the reactant will light only the lines.