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

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ANSI/<strong>NIST</strong>-ITL 1-<strong>2011</strong> - UPDATE 2013 DRAFT VERSIONscanning resolution, images meant <strong>for</strong> identification applications, such as those fromAppendix F certified devices (See Table 3) are restricted to a 1% tolerance from 500 ppi.With the deprecation of Record Types 3, 5 and 6, NTR in this version only directly appliesto Record Type-4. NTR does not apply to Type-7 records, unless so specified by animplementation domain.7.7.6.3.2 Variable-resolution Record Types t ransmittingresolution requirementFor variable-resolution friction ridge images (those in Record Types 13, 14, 15, 19 andpossibly in Record Types 16 and 20), the transmitting resolution shall be at least as greatas the class resolution of 500 ppi. There is no upper limit on the variable-resolution rate<strong>for</strong> transmission. However, the transmitting resolution shall not be greater than thescanning resolution. For variable resolution records the Transmitted horizontal pixelscale / THPS and the Transmitted vertical pixel scale / TVPS shall be specified. (SeeSections 7.7.8.4 and 7.7.8.5). Be<strong>for</strong>e transmitting variable-resolution records, theoperational capabilities of the sending and receiving systems should be addressed, andprior agreement should be made with the recipient agency or organization be<strong>for</strong>etransmitting the image.The migration path to higher transmitting resolutions is the same as <strong>for</strong> the scanningresolutions, i.e., from 500 ppi class to 1000 ppi class; from 1000 ppi class to 2000 ppiclass, etc. For images captured at a native scanning resolution greater than thepermissible upper limit of a transmitting resolution step in the migration path, it may benecessary to subsample, scale, or interpolate down. The result of this processing is toobtain a nominal scanning resolution that con<strong>for</strong>ms to a step in the transmissionmigration path.7.7.7 Sample qualityMany of the Record Types contain optional quality metric in<strong>for</strong>mation. In addition to thethree in<strong>for</strong>mation items described here, a quality field may contain other in<strong>for</strong>mationitems. Each of the in<strong>for</strong>mation items is contained in a subfield.Multiple subfields may be present, each indicating a different quality algorithm, up to amaximum of 9 times. This upper limit has been stated to maintain consistency across allencodings and record types. (In some places in the 2008 version, it was unlimited;another was limited to 1; some had 9. In 2007, some were limited to 4; others to 9.)The meaning attributed to this metric shall be defined and interpreted by the producer ofthe scoring algorithm or by the person or system used to assign the metric to the sample.The metric may be a predictor of false rejection per<strong>for</strong>mance or another metric indicatinga value associated with the quality of the sample <strong>for</strong> a particular function.[2013a>] Some quality fields have in<strong>for</strong>mation items preceeding the following threein<strong>for</strong>mation items. [

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