Wavelet scalar quantization
The Wavelet Scalar Quantization algorithm (WSQ) is a compression algorithm used for gray-scale fingerprint images. It is based on wavelet theory and has become an standard for the exchange and storage of fingerprint images. WSQ was developed by the FBI, the Los Alamos National Lab, and the National Institute for Standards and Technology (NIST).
This compression method is prefered over standard compression algorithms like JPEG because at the same compression ratios WSQ doesn't present the "blocking artifacts" and loss of fine-scale features that are not acceptable for identification in financial environments and criminal justice.