Patent ID: 7184581

Claim:
A system for measuring pafferns in a surface, especially in finger surfaces, the system comprising a number of sensor electrodes being provided with an electrically insulating material over which the surface being measured is to be moved, and at least one stimulation electrode for providing a varying current or voltage between the stimulation electrode and the number of sensors through the surface, characterized in that the sensor electrodes constitutes an essentially linear array, that the stimulation electrode is positioned separately from the array of sensor electrodes, that the system comprises a generator coupled to the stimulation electrode for applying a current or voltage with a varying amplitude or phase to the surface, and that the system comprises a measuring unit coupled to the sensor electrodes for, during the application of the current or voltage, measuring the impedance at the sensor electrodes relative to the stimulation electrode in a time sequence and calculating values of predetermined characteristics of the surface and combining the calculated values for the sensor electrodes over the time sequence for generating a representation of the surface pattern.