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

ANSI/NIST-ITL 1-2011Data Format for the Interchange of Biometric and Forensic Information13.7.4 EFS Paths and polygonA path is an ordered set of 2 to 99 vertices. The order of the vertices must be intheir consecutive order along the length of the path. No two vertices may occupythe same location. A path may not have any sides crossing. Each vertex isexpressed as an (X, Y) pair of positive integers in units of 0.01 mm.A closed path, or polygon, completes a circuit: the polygon side defined by thelast vertex and the first vertex shall complete the polygon. A polygon mustcontain at least 3 vertices. Polygons are used inField 9.300 Region of Interest / ROIField 9.324 Distinctive Features / DISField 9.357 Local Quality Issues / LQIAn open path is a series of connected points in which there is not an implicitconnection between the last and first vertices. Open paths are used in Field9.357 Ridge Path Segments / RPS). Each path is stored as a single data entry,with a comma separating the X and Y coordinates for a given vertex, and a dashseparating consecutive vertices. For example:• X1,Y1-X2,Y2-X3,Y3If multiple paths are present in the same field, they are separate subfields:• Subfield 1: X1,Y1-X2,Y2-X3,Y3• Subfield 2: X4,Y4-X5,Y5-X6,Y613.7.5 EFS Unknown, omitted or non-applicable valuesUnknown, omitted, or non-applicable values are left empty in the ExtendedFriction Ridge Feature fields. If values are not known or are not applicable, asimple field without information items shall not be included in the file.13.7.6 EFS No features presentThe following fields are used in this specification to indicate whether the absenceof a particular type of feature means that there are no instances of that type offield present, as opposed to simply not having been marked.For example, if there are no cores included in Field 9.320 Cores (COR), thenField 9.325 No Cores Present (NCR) would be set to “Y” if analysis determinedthat there were no cores discernable, but would have been omitted if analysishad not been conducted for cores.52DRAFT 2