The use of biometrics in electronic identification documents serves to verify the identity card bearer. That is, with the help of biometric characteristics, it can be determined more easily whether the person presenting the ID document is actually also the owner of the document. Thus, for example, two people that look almost identical to the human eye, can be distinguished with the help of a computer based facial comparison.
If this method is used e.g for border control, first the facial image is read out of the ID document, then a photograph is taken on site. These two images are then compared by means of a computer program. Slight changes in appearance, such as a different hairstyle, have no influence on the results of this test.
However, it is important that the biometric features stored on the identity document have at least a certain level of quality. Therefore, in various technical guidelines of the BSI, ISO and ICAO uniform standards are defined on how the characteristics are collected and how the quality has to be checked (e.g. TR-03121 – Biometrics in public sector applications). Thus, the biometric processes can be applied in international border traffic.