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

ANSI/NIST-ITL 1-2011 - UPDATE 2013 DRAFT VERSIONalgorithm be used for latent images.The following paragraphs apply to exemplar images.Wavelet Scalar Quantization (WSQ) shall be used for compressing grayscale friction ridgedata at 500 ppi class for new systems. In order to maintain backward compatibility,legacy systems may use JPEGB or JPEGL for compressing 500 ppi class images.WSQ version 3.1 40 or higher shall be used for WSQ compression of grayscale fingerprintdata at the 500 ppi class with a platen of 2 inches or greater in height. WSQ 2.0 or highermay be used for 500 ppi class data taken from a platen of less than 2 inches in height.WSQ shall not be used for other than the 500 ppi class. Any certified WSQ software isable to decode images with an encoder certified for WSQ specification versions 2.0, 3.0or 3.1. The decoder is the same for all three versions of the specification.Field 4.008: Compression algorithm / GCA54 only allows the Code values of 0 and 1(See Table 15) for new systems, since for such systems only uncompressed or WSQcompressed500 ppi images may be transmitted in Type-4 records.For friction ridge images at the 1000 ppi class, JPEG 2000 shall be used according to thespecifications and options contained in Profile for 1000 ppi Fingerprint Compression.7.7.9.2 Use of compression algorithms for iris imagesFor iris images, images may be uncompressed or compressed. The compression code shallbe one of the following, entered in Field 17.011: Compression algorithm / CGA:• NONE – An entry of “NONE” indicates that the data contained in this record isuncompressed. The image shall be represented as an array of n rows by m columns.Each pixel in a monochrome image shall be represented by eight or more bits. Colorimages shall be represented as a sequential sample of a red, green, and blue intensityfor each pixel (if using RGB - See Section 7.7.10.3). The image shall be organizedin row-major order, with the lowest address corresponding to the upper left corner ofthe image.• PNG – This supports lossless compression. PNG is formally standardized (ISO/IEC15948) and implementations are freely available 41 (libpng).• JP2 and JP2L - As with other biometrics, while lossless compression is preferred,iris images can be lossy-compressed. The image type (Field 17.032: Iris storageformat / ISF) should be selected appropriately, and the compression ratio should beset to satisfy some known quantified storage or transmission bandwidth limitation.The baseline JPEG algorithm (ISO/IEC 10918) is not acceptable for iris images and shallnot be used. It has been shown that false match rates increase due to the presence of tilingartifacts. While JPEG was allowed in prior versions of this standard for iris compression, it40WSQ 3.1 rectifies problems associated with compression of larger images in earlier version of WSQ. Seehttp://biometrics.nist.gov/cs_links/wsq/WSQ_notice.pdf . The problem was associated with takingimages of two thumbs at the bottom of the platen area.41See http://www.libpng.org/pub/png/libpng.html88