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

ANSI/NIST-ITL 1-2011 - UPDATE 2013 DRAFT VERSIONTable 34 Ridge quality map data representation format optionsType Code DescriptionUncompressed(concatenateddecimal)UNCThe values for each grid cell in the Ridge Quality Map field are single-character integers as definedin Table 33, with one character per cell. All quality values for one row are concatenated left to right,with one repeating subfield of Field 9.308: EFS ridge quality/confidence map / RQM for each row.The number of characters in one repeating subfield of Field 9.308 is the same as the number of cellsin one row: the Region of Interest’s width divided by the Grid Size, rounded up to the nearest integer.Run-LengthEncodedRLEThe unencoded values for each entry are identical to those used in UNC format. The numeric valuesfor each grid cell (0-5) are then replaced with alphabetic equivalents (A-F), and then any sequentialruns of the same character are prefixed by the decimal count of repeated characters. Individualcharacters are not preceded by a count.For example:00000000000000000000000000000000000000000000000000 (50 characters)Is saved as “50A”0000000000001122334555555444442210000000000000000 (50 characters)Is saved as “12A2B2C2DE6F5E2CB16A” (20 characters)8.9.7.8 Field 9.310: EFS ridge flow map / RFMThis optional field contains the direction of friction ridges at sampling points throughoutthe region of interest. The sampling frequency is optionally defined in Field 9.311: EFSridge flow map format / RFF, and otherwise defaults to 0.41 mm in uncompressedformat. The first sampling point in the image is the top left-most point in the region ofinterest. The same sampling frequency is used both horizontally and vertically. Valuesshall be included for all sampling points in the region of interest, even if the samplingpoints are at the edge of the region of interest. For each sampling point, angles shall bereported in integer degrees, with 0 degrees to the right (horizontal), increasingcounterclockwise to a maximum value of 179° (since 180°=0°). Undefined angles arerecorded in Field 9.311: EFS ridge flow map format / RFF. Each subfield correspondsto one row of the map in order from top to bottom.The area used for determining direction (window size) may be larger or smaller than thesampling frequency. Different window sizes may be used within a single image, at thediscretion of the implementer. For example, an implementer may choose to use a uniformwindow size except in areas of high curvature, in which a smaller window size may be used.May, 2013 DRAFT VERSION UPDATE 2013 Page 151