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

ANSI/NIST-ITL 1-2011Data Format for the Interchange of Biometric and Forensic InformationThe second information item (horizontal offset / PVY) is the pixel count downfrom the origin at the upper left corner of the image.Table 73 Iris boundary definition codesCode TypeNumberof pointsDescriptionC Circle 2 The boundary is defined by two points: the center isdefined in the first subfield, and any point on thecircle is defined in the second subfield.E Ellipse 3 The boundary is defined by three points: bothendpoints of one of the ellipse’s axes are defined inthe first and second subfields, and one endpointfrom the other axis is defined in the third subfield.P Polygon n The boundary is defined as an n-vertex polygon,where “n” is between 3 and 99. The order of thevertices must be in their consecutive order aroundthe perimeter of the polygon, either clockwise orcounterclockwise. No two vertices may occupy thesame location. The polygon side defined by the lastsubfield and the first subfield shall complete thepolygon. The polygon must be a simple, planefigure with no sides crossing and no interior holes.21.31 Field 17.034 Iris Sclera Boundary / ISBThis optional field defines the limbic boundary, between the iris and sclera. Thisfield shall consist of the following:The first subfield (Iris sclera code / ISC) is one ASCII character containing thecode from Table 73The second subfield (number of points defined / ISPQ) is a numeric value ofthe total number of points describing the boundaryThe third subfield (consecutive points / SCP) contains two information items.The first information item (horizontal offset / SHX) is the pixel count acrossfrom the origin at the upper left corner of the image.The second information item (horizontal offset / SVY) is the pixel count downfrom the origin at the upper left corner of the image.214DRAFT 2