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

ANSI/NIST-ITL 1-2011Data Format for the Interchange of Biometric and Forensic InformationIf the SRT field contains the equivalent of the value of two, then this field shallcontain a list of vectors that describes the pen position. Each of the entries is asubfield.• The first subfield is a horizontal coordinate value / HCV.• The second subfield is a vertical coordinate value / VCV.• The third subfield is the pen pressure value / PPV of line segmentswithin the signature.Both the X (VHC) and Y (VVC) coordinates shall be expressed in units of .0254mm (.001 inches) referenced from the bottom leftmost corner of the signature 18 .Positive values of X shall increase from left-to-right and positive values of Y shallincrease from bottom-to-top.The pen pressure (VPP) shall be a constant value until the next vector becomesactive. A value or pressure of “0” shall represent a "pen-up" (or no pressure)condition. The value of “1” shall represent the least recordable pressure for aparticular device, while “254” shall represent the maximum recordable pressurefor that device. To denote the end of the vector list, “255” shall be inserted in thisentry.13 Type-9 minutiae data recordType-9 records shall contain ASCII text describing minutiae and relatedinformation encoded from a finger, palm, or plantar image. There is no limit onthe number of Type-9 records for a latent search transaction. The Type-9 recordshall also be used to exchange minutiae and related information from latentfriction ridge images between similar or different systems.Minutiae information may be extracted and encoded in any of several differentmanners depending on the system that is used to scan an image, extractminutiae, and encode the minutiae template.Each minutia shall be identified by an index number that is assigned to it. Thenumbering shall begin at "1" and be incremented by "1" for as many times asthere are minutiae encountered. This allows each miniutia to be uniquelyidentified. The numbering of the minutiae shall be unordered.As required, ridge counts shall be determined from each minutia in a fingerprintor palmprint to certain other neighboring minutiae. When this occurs, ridgecounts between designated minutiae shall be associated with the applicableindex numbers so as to ensure maintenance of the proper relationships.Brad Wing 6/19/10 5:07 PMComment: Reworded•18 This is not the same coordinate system as described in Section4.739DRAFT 2