1. A method for digitizing at least a subarea of the papillary structure of the skin, the subarea defining an intensity profile with a continuous intensity domain, comprising the steps of: transforming the intensity profile into at least one analog electrical signal, and transforming said analog electrical signal into at least one digital signal with an intensity domain comprising discrete intensity values and a space domain comprising discrete positions, repeatedly performing the transforming steps for the same subarea to form a plurality of different digital signals, and combining the plurality of digital signals into a common digital papillary structure signal with an intensity domain formed from discrete intensity values and a space domain formed from discrete positions in such a way that the intensity domain of the papillary structure signal has more intensity values than the intensity domains of each single one of the plurality of digital signals.