acknowledgements for ansi/nist-itl 1-2011 - NIST Visual Image ...

ANSI/NIST-ITL 1-2011 - UPDATE 2013 DRAFT VERSIONFigure 1: Source Representation IndicesRECORD TYPE-20DATA RECORD WITH THE APPROPRIATESOURCE REPRESENTATIONField xx.997 / SORSubfield k (there can be multiplesource representations)information item SRN value = a ← Field 20.021 / SRN value = ainformation item RSP value = z ← Field 20.016 / SEGSubfield j (for the proper segment)information item RSP value = z7.3.3 Associated context / ASCNew to the 2011 version of the standard, optional field xx.995 is contained in biometric datasample Record Types 10 and above that may have instances of Record Type-21 linked toit. Record Type-21 stores images and/or recordings that are not the actual source of thebiometric data contained in another Record Type, but do show the context of the biometricdata. An example would be a crime scene photograph showing the location of a glass thathad latent prints on it. However, the close-up image of the latent prints could appear in aType-20 record (since that is the image that the individual fingerprint images are derivedfrom), with the segmented individual images appearing in Type-13 records. This fieldconsists of a maximum of 255 repeating subfields, each of which contains two informationitems, as described below. This is because there may be multiple instances of associatedcontext records associated with a single biometric sample. Figure 2 illustrates therelationship of the fields and information items.7.3.3.1 Associated context number / ACNThe first information item contains the associated context number / ACN for a particularRecord Type-21. This is mandatory for each Field xx.995, when the field is used. Itcontains an index to a particular instance of a Type-21 record in the transaction. This sameindex value appears in the appropriate instance of Record Type-21 as Field 21.021:Associated context number / ACN. The value of the ACN shall be a sequentially assigneda positive integer starting from one and incremented by one, not to exceed 255.7.3.3.2 Associated segment position / ASPThe second information item in Field xx.995 is optional. It is the associated segmentposition / ASP. It contains the index to a particular set of segmentation coordinates of theassociated context data. This same segmentation index value appears in Record Type-21 asthe associated segment position / ASP in Field 21.016: Segments / SEG. There may be50