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

ANSI/NIST-ITL 1-2011 - UPDATE 2013 DRAFT VERSION“2.000000123:”.For purposes of illustration throughout this annex, a three-digit number shall be used forenumerating the fields contained in each of the Record Types, other than 4, 7 and 8. Fieldnumbers will have the form of “TT.xxx:” where the “TT” represents the one- or twocharacterrecord type followed by a period. The next three characters comprise theappropriate field number followed by a colon. Descriptive ASCII information or the sampledata follows the colon.Logical Type-1, Type-2, and Type-9 records contain only ASCII textual data fields (SeeAnnex A: Character encoding information). The entire length of the record (includingfield numbers, colons, and information separators) shall be recorded as the first ASCII fieldwithin each of these record types. The ASCII File Separator “ F S” control character (signifyingthe end of the logical record or transaction) shall follow the last byte of ASCII informationand shall be included in the length of the record.The Record Type-4: Grayscale fingerprint image, the Record Type-7: User-definedimage record and the Record Type-8: Signature image record contain only binary datarecorded as ordered fixed-length binary fields. The entire length of the record shall berecorded in the first four-byte binary field of each record. For these binary records, neitherthe record number with its period, nor the field identifier number and its following colon,shall be recorded. Furthermore, as all the field lengths of these three records are either fixedand specified, none of the four separator characters (“ U S”, “ R S”, ” G S”, or “ F S”) shall beinterpreted as anything other than binary data. For these binary records, the “ F S” charactershall not be used as a record separator or transaction terminating character.Each ASCII field contains a numeric field identifier and its descriptive data.When Field 999 is present in a record, it shall appear as the last entry in the record and shallcontain the data placed immediately following the colon (“:”) of the field identifier. Therecord length field shall contain the length of the record. The ASCII File Separator “ F S”control character shall follow the last byte of the compressed or uncompressed sample data.The “ F S” character shall signify the end of the logical record or transaction and shall beincluded as part of the record length.The Base-64 encoding scheme (See Annex A: Character encoding information) shall beused for converting non-ASCII text into ASCII form. The field number including the periodand colon, for example “2.001:”, in addition to the “ U S”, “ R S”, “ G S”, and “ F S” informationseparators shall appear in the transaction as 7-bit ASCII characters without conversion toBase-64 encoding.B.1.6Switching between character encoding setsAll of the fields in the Type-1 record shall be recorded using the 7-bit ASCII code, which isthe default character encoding set code within a transaction. In order to effect data andtransaction interchanges between non-English speaking or foreign-based agencies, atechnique is available to encode information using character encoding sets other than 7-bitMay, 2013 DRAFT VERSION UPDATE 2013 Page 449