ANSI/NIST-ITL 1-2011 - NIST Visual Image Processing Group ...

ANSI/NIST-ITL 1-2011Data Format for the Interchange of Biometric and Forensic Information• The fifth information item (Radius of position uncertainty / MRU) definesthe radius of a circle centered at the location (X,Y) of the minutia 35• The sixth information item (Direction uncertainty / MDU) contains aninteger value from “0” (default) to “180” indicating the precision in thedirection (theta) of the minutia, measured in degrees. The resultingdirection is Theta±Uncertainty°. 36Distinctive Features (DIS).•35 The circle is sized to include the area of other possible locations of the minutia, if the precise location cannotbe determined (such as due to poor consistencyof presentation). If the location is known precisely, the radius of positionuncertainty may be omitted or set to 0. The radius of uncertainty is measured in integer units of 10 micrometers (0.01mm),and may overlap the edge of the Region of Interest.36Examples of cases in which confidence in direction may be low include cases when the ridge stops or bends close tothe minutia so that a good angle measurement cannot be taken, or cases with three equally spaced legs.•98DRAFT 2