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

ANSI/NIST-ITL 1-2011Data Format for the Interchange of Biometric and Forensic InformationThis field may contain one or more (latent quality metric subfields / LQS),each consisting of four information items. This subfield is repeated for each latentimage and quality algorithm used.177The first information item is the code / FGP as chosen from Table 9.The second information item shall be a quantitative expression of thepredicted matching performance of the biometric sample, which is a qualityvalue / QVU. This item contains the ASCII representation of the integer imagequality score between 0 and 100 assigned to the image data by a qualityalgorithm. Higher values indicate better quality. An entry of “255” shallindicate a failed attempt to calculate a quality score. An entry of “254” shallindicate that no attempt to calculate a quality score was made. The use ofadditional values to convey other information should be harmonized withISO/IEC 19794 standards.The third information item shall specify the ID of the vendor of the qualityalgorithm used to calculate the quality score, which is an algorithm vendoridentification / QAV. This 4-digit hex value is assigned by IBIA and expressedas four ASCII characters. The IBIA shall maintain the Vendor Registry ofCBEFF Biometric Organizations that will map the value in this field to aregistered organizationThe fourth information item shall specify a numeric product code assigned bythe vendor of the quality algorithm, which may be registered with the IBIA, butregistration is not required. This is an algorithm product identification / QAPthat indicates which of the vendor’s algorithms was used in the calculation ofthe quality score. This field contains the ASCII representation of the integerproduct code and should be within the range 1 to 65,535.17.4.16 Fields 13.200-990: User-defined fields / UDFThese fields are user-definable fields. Their size and content shall be defined bythe user and be in accordance with the receiving agency. If present they shallcontain ASCII textual information.17.5 Field 13.996: Image hash / HASThis optional field has the hash value of the image contained in the 999 field ofthis record, hash value shall be calculated using SHA 256.17.6 Field 13.997: Original image reference / OIVThis optional field refers to an image in Record Type-20 with the same OIR. Thisis an optional field and is used when the image transmitted in this record isderived from an original image. This field consists of two subfields.The first subfield contains the reference code / OIR for a particular RecordType-20. This is mandatory for each OIV.DRAFT 2