An Exploration of the Operational Ramifications of Lossless Compression of 1000 ppi Fingerprint Imagery

The criminal justice communities throughout the world exchange fingerprint imagery data primarily in 8-bit gray-scale and at 500 pixels per inch1 (ppi) or equivalently 19.7 pixels per millimeter (ppmm). The Wavelet Scalar Quantization (WSQ) fingerprint image compression algorithm has been developed and maintained by the Federal Bureau of Investigation (FBI), Los Alamos National Laboratory and the National Institute for Standards and Technology (NIST) as the standard for compressing 500 ppi fingerprint imagery in the United States. WSQ is classified as a "lossy" compression algorithm. Lossy compression algorithms employ data encoding methods which discard (lose) some of the data in the encoding process in order to achieve an aggressive reduction in the size of the data being compressed. Decompressing the resulting compressed data yields content that, while different from the original, is similar enough to the original that it remains useful for the intended purpose. The WSQ algorithm allows users to specify how much compression is to be applied to the fingerprint image at the cost of increasingly greater loss in fingerprint image fidelity as the effective compression ratio is increased (see Figure 1 for an example of image degradation from lossy compression).

Author: U. S. Department of the Interior

Publisher: Createspace Independent Publishing Platform

Publication Date: Jul 23, 2014

Number of Pages: 54 pages

Binding: Paperback or Softback

ISBN-10: 1499734905

ISBN-13: 9781499734904